Youths Happier During Lockdown

Welcome back. Among the interesting studies published during my hiatus was one from researchers with Cambridge and Oxford universities. They found the self-reported mental health and wellbeing of 1 in 3 youths improved during England’s first COVID-19 lockdown. 

Self-reported change in mental wellbeing of 16,940 youths during England’s first COVID-19 lockdown (from link.springer.com/article/10.1007/s00787-021-01934-z).

Improved? Wait. That’s not what I’ve been hearing and reading. Has the media overstated the issue? Here’s what the U.S. Surgeon General wrote on 7 December 2021:

Before the COVID-19 pandemic, mental health challenges were the leading cause of disability and poor life outcomes in young people, with up to 1 in 5 children ages 3 to 17 in the U.S. having a mental, emotional, developmental, or behavioral disorder…

The pandemic added to the pre-existing challenges that America’s youth faced…This Fall, a coalition of the nation’s leading experts in pediatric health declared a national emergency in child and adolescent mental health.

The UK study doesn’t detract from the crisis, it simply adds perspective: not every youth got worse. Determining why one-third fared better might provide insight for promoting youth mental health and wellbeing going forward.

Data for Analysis
The researchers used data from the OxWell Student Survey, a recurring, cross-sectional, self-report survey relating to mental health and wellbeing. The school-base survey of England’s students, aged 8 to 18, contains questions repeated in each iteration as well as new questions added in response to social and environmental events and emerging research.

For the current study, 16,940 students were surveyed June-July 2020 at the tail end of England’s first national lockdown. They answered questions about their experiences with the pandemic, school, home, lifestyle, relationships and more.

Examining the Data
The study was limited to a descriptive analysis of data, which is probably sufficient to highlight major differences without resorting to statistical testing. Descriptive analysis is also the simplest way for me to summarize key findings from the reported results.

Toward that end, I’ve prepared a table relating the youths’ self-reported changes during the lockdown to the number of those whose mental wellbeing got better, worse or remained the same. I’ve listed 14 items derived from a table the researchers reported with over 100 items. This is not to say the reported detail wasn’t significant; only that it’s well beyond the scope of what I needed to capture some core findings. I encourage you to review the paper to pursue the topic in greater depth. 

Relationships of selected variables with self-reported change in mental wellbeing of 16,940 youths during England’s first COVID-19 lockdown (modified from Table 2 of link.springer.com/article/10.1007/s00787-021-01934-z).

Overall, the mental wellbeing of surveyed males and younger students tended to improve during the lockdown while surveyed females and older students tended to get worse.

The students whose mental wellbeing improved during the lockdown self-reported that they were able to get all the academic help they needed at home, managed school tasks better, were bullied a little less, had better relationships with friends and family, felt less left out and less lonely, and exercised as well as slept more.

Wrap Up
As the researchers point out, the survey showed that students who reported improved mental health and wellbeing were more likely than their peers to report improvement across the full range of school, relational and lifestyle factors.

The impact of lockdown was dependent on a number of factors, such as gender, pre-pandemic mental health, social relationships, school connectedness, online learning experience, family composition and family financial situation.

While the crisis is real, many students did indeed experience improved mental health and wellbeing. Thanks for stopping by.

P.S.
Study of UK students during lockdown in European Child & Adolescent Psychiatry journal: link.springer.com/article/10.1007/s00787-021-01934-z
Article on study on EurekAlert! website: www.eurekalert.org/news-releases/944267
U.S. Surgeon General’s advisory: www.hhs.gov/about/news/2021/12/07/us-surgeon-general-issues-advisory-on-youth-mental-health-crisis-further-exposed-by-covid-19-pandemic.html
Oxwell Student Survey and information for parents:
bmjopen.bmj.com/content/11/12/e052717
www.psych.ox.ac.uk/research/schoolmentalhealth/parent-information-sheet-1

Walking Revisited

Stop the presses! Oh, Darn. Too late. The blog post said walking improved health and lowered the risk of death. But it didn’t say that moderate to vigorous exercise will do much more than walking for your fitness.

Welcome back. A month ago, I blogged about three studies that found walking was great with more steps generally associated with lower all-cause mortality (see Just Keep Walking). That seemed reasonable, but the studies also found no significant association between how fast one walks and mortality after adjusting for total steps per day.

All-cause mortality vs steps per day among U.S. adults age 40 or older (figure used in Just Keep Walking, from jamanetwork.com/journals/jama/fullarticle/2763292).

Though I expressed my surprise, I did find other studies that also reported any level of physical activity, regardless of intensity, was associated with a substantially lower risk of death.

Well, that was last month. In the meantime, news was released of another study that found moderate-vigorous physical activity boosts fitness three times more than walking.

Now that’s not surprising. Shall we look at that study?

Testing Physical Activity for Fitness
A team of investigators led by researchers with Boston and Harvard universities set out to better define the relationship between physical activity and physical fitness.

They enlisted 2,070 Framingham Heart Study participants (age 54 ± 9 years, split between men and women) to test how (1) moderate-vigorous physical activity (exercise), (2) low-moderate physical activity (steps/day walking) and (3) minimizing sedentary physical activity translate to cardiorespiratory fitness.

The participants wore accelerometers to measure the intensity and frequency of exercise, steps/day and sedentary times for two 8-day periods, 7.8 years apart. During the second period the participants’ cardiorespiratory fitness was assessed on a cycle ergometer with breath-by-breath gas exchange data obtained during four stages of exercise, initiation to recovery.

Activity levels and VO2 of 2,070 participants during second period; VO2 measured as milliliters of oxygen used in one minute per kilogram of body weight (from academic.oup.com/eurheartj/advance-article-abstract/doi/10.1093/eurheartj/ehab580/6357860).

Example of cycle ergometer measurement of VO2 (photo from www.endurancedave.com/post/whats-the-best-training-protocol-for-your-fastest-1-hour-cycling-effort).

The principal measure of cardiorespiratory fitness was peak oxygen uptake (VO2), which denotes the highest oxygen uptake reached during exercise to voluntary exhaustion.

Principal Findings
Here are the three study results that I found most interesting:

To achieve the equivalent change in cardiorespiratory fitness, each minute increase in moderate-vigorous physical activity (exercise) would require at least 3 minutes of intermediate cadence walking and at least 14 minutes less sedentary activity. 

Activity levels and VO2 of 2,070 participants during second period (from academic.oup.com/eurheartj/advance-article-abstract/doi/10.1093/eurheartj/ehab580/6357860).

As you would expect, participants with either higher moderate-vigorous physical activity or higher steps/day had higher fitness levels. But this was regardless of how much time they spent sedentary. It appears that much of the negative effect that being sedentary has on fitness may be offset by higher levels of exercise and walking.

Participants with high activity values at one period and low activity values at the other, 7.8 years apart, had equivalent levels of fitness. There may be a “memory effect” of previous physical activity on current levels of fitness.

Wrap Up
The earlier studies reported that increased steps/day was associated with lower rates of mortality, though it tended to reach a limit.

In the recent study, increased steps/day was associated with higher fitness levels. The lead researcher noted there was no evidence of a threshold beyond which higher levels of activity were no longer associated with greater fitness.

Fitness isn’t mortality, but they’re sure related. If you’d like to improve your fitness, try increasing the level of exertion through exercise or by picking up the pace. (The study categorized 60-99 steps/minute as low-level exertion, 100-129 steps/minute as moderate and greater than 130 steps/minute as vigorous.)

Be well and thanks again for stopping by.

P.S.
Study of physical activity and fitness in European Heart Journal: academic.oup.com/eurheartj/advance-article-abstract/doi/10.1093/eurheartj/ehab580/6357860
Article on study on EurekAlert! website: www.eurekalert.org/news-releases/929580
Cardiopulmonary exercise testing: www.massgeneral.org/medicine/pulmonary/treatments-and-services/cardiopulmonary-exercise-testing

Just Keep Walking

Welcome back. As important as it was, perhaps last week’s blog post endorsing exercise was too much for some, especially referencing the 2016 European Guideline of at least 150 minutes/week of moderate intensity or 75 minutes/week of vigorous activity, or some combination (Time to Get Active). By the way, that’s also the current guideline of the American Heart Association.

If it was too much, you could just take a walk.

How Many Steps?
If you were following this blog in 2015, you might recall a two-part, guest blog post on walking to stay fit by a then-recently retired elementary school principal in Ontario, Canada (Stepping into Fitness, Part 1, Stepping into Fitness, Part 2).

When her fitness began to ebb with retirement, and her entire wardrobe seemed to have mysteriously shrunk, she was ready for a change. For Christmas, her son gave her a wristband monitor to encourage her to walk regularly and record the number of steps on her computer or smartphone.

The newly retired school principal (in red) with members of a local walking club (from Stepping into Fitness, Part 1).

She adopted the goal of 10,000 steps per day, roughly 5 miles. In the 1960s, Japan’s pedometer companies and walking clubs were promoting 10,000 steps daily as a way to achieve fitness. At the time of her writing, the American Heart Association was also recommending 10,000 steps for improved health and decreased risk of heart disease. Should 10,000 steps be your goal?

Recent Findings on Steps and Intensity
To help you decide, I’ll summarize the findings of three studies.

National Cancer Institute researchers led a study published in 2020 that assessed the associations of daily step counts and intensity (cadence) with all-cause mortality.

A representative sample of 4840 U.S. adults (mean age 56.8; 54% female) wore accelerometers to count steps for a mean of 5.7 days. Over a mean follow-up of 10.1 years, there were 1165 all-cause mortality deaths. The rate of deaths fell with increased steps--64% of those who took fewer than 4000 steps/day, 28% of those who took 4000 to 7999 steps/day, 11% of those who took 8000 to 11,999 steps/day, and 9% of those who took at least 12,000 steps/day.

All-cause mortality vs steps per day among U.S. adults age 40 or older (from jamanetwork.com/journals/jama/fullarticle/2763292).

There was no significant association between step intensity and mortality after adjusting for total steps per day.

All-cause mortality vs steps per day among U.S. adults by age (from jamanetwork.com/journals/jama/fullarticle/2763292).

University of North Carolina investigators led a team that conducted a study presented at a 2021 American Heart Association Conference.

The researchers analyzed daily steps, walking patterns and all-cause mortality of 16,732 women (mean age 72; mostly white, non-Hispanic) who had worn a waist step counter for 4 to 7 days. Each participant’s steps were divided into: (1) bouts of walking 10 minutes or longer with few interruptions and (2) short spurts of walking during regular daily activities. Over a mean follow-up of 6 years, there were 804 deaths.

The researchers found:
- Each initial increase of 1000 steps/day over no daily steps had 28% fewer deaths.
- Exceeding 2000 steps/day in uninterrupted bouts had 32% fewer deaths.
- Participants who took more steps in short spurts lived longer regardless of how many steps they took in longer, uninterrupted bouts; however, the short-spurt benefits leveled off at about 4500 steps/day.

A University of Massachusetts investigator led a research team in the most recent assessment of steps/day and all-cause mortality.

Steps and intensity of 2110 participants (mean age 45.2, 57.1% female, 42.1% Black) were monitored with an accelerometer for 7 days; 72 participants died during the mean follow-up of 10.8 years.

Grouping steps/day as low (fewer than 7000), moderate (7000-9999) and high (10,000 or more), the team found the risk of all-cause mortality associated with low steps/day to be 28% greater than with moderate steps/day and 45% greater than with high steps/day. There was no association of step intensity with mortality.

Wrap Up
I was surprised that step intensity--how fast one walks--is not associated with mortality; but other studies have also found that any level of physical activity, regardless of intensity, is associated with a substantially lower risk of death.

How many steps should you walk? Do what you can, knowing that more steps per day, all at once or in shorter spurts, could improve your health and help you live longer. Be well and thanks for stopping by.

P.S.
American Heart Assoc. fitness guidelines: www.heart.org/en/healthy-living/fitness/fitness-basics/aha-recs-for-physical-activity-in-adults
National Cancer Institute led study in JAMA Network Open: jamanetwork.com/journals/jama/fullarticle/2763292
Univ. of North Carolina led study presented at American Heart Assoc. Conference: newsroom.heart.org/news/taking-more-steps-daily-may-lead-to-a-longer-life
Univ. of Massachusetts led study in Jama Network Open: jamanetwork.com/journals/jamanetworkopen/fullarticle/2783711

It’s Time to Get Active

Welcome back. In the earliest days of this blog, I described the evolution of my daily exercise routine (Time to Exercise). The foundation was laid on a UN project in 1982, during which our team visited the Tien Shan Mountains in northwestern China. When I returned to Cornell, my mentor, colleague and friend, Prof. Ta Liang, who had come to the U.S. from China after World War II, advised me that, because I’d seen Heavenly Lake, I would live forever.

Warren and UN project counterparts at Heavenly Lake, Tien Shan Mountains, Xinjiang, China.

Although I trusted Ta implicitly, as I got older, I decided that I’d better hedge my bet. I started exercising.

All this is to say that starting to exercise at any age can have major health benefits. This was shown in a study presented at the European Society of Cardiology Congress by a researcher at Switzerland’s University of Bern.

Sidebar
I was hesitant to blog about this study for a few reasons: (1) the research was presented at a conference, not published in a peer-reviewed journal; (2) I’d be blogging about a study, without seeing the paper; and (3) the research focused on health benefits for coronary heart disease patients.

I went ahead for a few reasons: (1) though the conference submission may not have been peer-reviewed, the study involved a meta-analysis of published research that would have been peer-reviewed; (2) the study focused on cardiovascular disease mortality but included all-cause mortality; (3) considering the research and researcher, the paper will likely be published if submitted; and (4) I didn’t want to wait a year to share the findings.

The New Study
The researcher conducted a meta-analysis, combining results from nine separate studies, to investigate the relationship of physical activity with the risk of cardiovascular disease death. In all, 33,576 patients (average age 62.5 years, 34% female) with coronary heart disease were included.

The patients were classified as physically active or inactive using validated questionnaires at baseline and after a median of 7.2 years. Definitions of active and inactive varied across the different studies but were in line with the 2016 European Guidelines on cardiovascular disease prevention in clinical practice for healthy people--at least 150 minutes/week of moderate intensity or 75 minutes/week of vigorous activity, or some combination.

Patients were categorized into four groups according to their activity status at both baseline and follow-up: inactive over time, active over time, increased activity over time, and decreased activity over time. All of the studies defined “increased activity over time” as changing from the inactive to the active category and “decreased activity over time” as changing from the active to the inactive category.

Each of the four groups was assessed against the risks of all-cause and cardiovascular disease deaths at 7.2 years after baseline.

Wrap Up
Compared to patients who were inactive over time, the risk of all-cause death was 50% lower in those who were active over time, 45% lower in those who were inactive but became active, and 20% lower in those who had been active but became inactive.

Continuing the same comparison, the risk of death due to cardiovascular disease, was 51% lower in those who remained active over time, 27% lower for those who were inactive but became active, and statistically the same for those whose activity decreased over time.

Although regular physical activity over the years offered the greatest longevity, starting later in life offered heart disease patients significant survival benefits. But those benefits were reduced or even lost if the physical activity was not maintained.

So do yourself a favor--continue or start exercising. Thanks for stopping by. 

Some of Warren’s low-cost exercise paraphernalia: stationary bike (especially for bad weather, less than $200), running/walking shoes, mat, free weights, bungee cord, shorts, hat, t-shirt (optional for predawn), reflective vest (mainly for predawn); dress warmer in winter.

P.S.
The European Society of Cardiology (ESC): www.escardio.org/The-ESC
ESC Congress 2021--The Digital Experience: www.escardio.org/Congresses-&-Events/ESC-Congress
Congress program: digital-congress.escardio.org/ESC-Congress/programme
Study author: www.ispm.unibe.ch/about_us/staff/gonzalez_nathalia/index_eng.html
Study title: Physical activity trajectories are associated with the risk of all-cause and cardiovascular disease mortality in patients with coronary heart disease. A systematic review and meta-analysis.
Article on study on EurekAlert! website: www.eurekalert.org/news-releases/925989
European Guidelines on cardiovascular disease prevention: www.ncbi.nlm.nih.gov/pmc/articles/PMC4986030/

Rinse Pink to Run

Welcome back. You may recall that, eight months ago, I blogged about a study that found rinsing with an antibacterial mouthwash after exercise reduced the blood-pressure lowering effect of exercise (Skip Mouthwash After Exercise). The study was led by an investigator from the UK.

Well, there’s another mouth-rinsing, exercise-related study by UK researchers. But that’s where the similarities end.

The recent study by researchers affiliated with the UK’s Loughborough College and University of Westminster examined the effect of a mouth rinse’s color on exercise performance. Although the study sample was small, the findings could be big, maybe a new avenue of future research in sports drinks and exercise.

Pick a mouth rinse for exercising, clear or pink.

Study Premise
The researchers began with recognition that a carbohydrate mouth rinse commonly produces a well-documented 2% to 3% benefit in running and cycling performance during exercise sessions up to 1 hour duration. A carbohydrate mouth rinse also activates the reward and motor function areas of the brain, improving pleasure, arousal and motor output during high-intensity or prolonged exercise.

The researchers also recognized that the consumption of food and drink is a multisensory experience, with color often manipulated to enhance taste perception and psychophysiological response. In that context, the perception of sweetness is enhanced if a food or drink product appears pink.

Given that the color pink is associated with sweetness and the expectation of sugar-carbohydrate intake, they reasoned that a pink-colored mouth rinse that had no carbohydrate might elicit a benefit similar to that of a carbohydrate mouth rinse through a placebo effect.

They then set out to determine if mouth rinsing with a pink, non-caloric, artificially sweetened solution could improve self-selected running speed and distance covered during a 30-min run.

Study Design and Execution
The researchers recruited 10 healthy volunteers (6 male, 4 female; age 30 ± 3 years) who regularly ran at least 3 times/week and were judged fit by a readiness questionnaire.

The participants visited the laboratory on three occasions (one preliminary and two experimental trials), each separated by one week. The experimental trials were randomized for each participant.

Preliminary Trial:  The participants watched a video that detailed the benefits of a carbohydrate mouth rinse and were informed that the study aimed to compare the effects of mouth rinsing two commercial sports drinks. The true aim of the study and rinse content were not disclosed until the study was completed.

The two rinses were prepared identically by adding 0.12-grams of pure sucralose to 500-milliliters of plain water. Two drops of non-caloric pink colorant were added to one rinse; the other remained clear.

After the video, the participants were given a full familiarization of the experimental protocol during which they were asked to rinse their mouth with unsweetened clear water.

Experimental Trials: Each experimental trial required participants to exercise on a motorized treadmill set at a gradient of 1.0%.

The trials included a warm-up (2-min walk, 10-min run) and a 30-min, self-paced running protocol. For the latter, participants were instructed to self-select the speed necessary to maintain a rating of perceived exertion (RPE) of 15 (hard/heavy).

During each trial, the participants rinsed for 5-seconds with 25-milliliters of one of the randomly assigned solutions on 9 occasions--4 during the warm-up, 5 during the 30-min run.

The researchers recorded the distance run and mean speed for the entire 30-min and at 5-min intervals. They also measured heart rate, felt arousal (6 point scale) and pleasure/displeasure (11 point bipolar scale) 30-seconds prior to each mouth rinse and on run completion. Following the second experimental trial, they interviewed the participants to determine perceived differences in distance covered and drink ratings between trials.

Distances (meters) and speeds (kilometers/hour) measured when running with a clear or pink mouth rinse. A and C: Bar charts show overall mean differences during the 30-minute run; dashed lines show individual responses; B and D: Lines and divisions show differences at 5-minute intervals (from www.frontiersin.org/articles/10.3389/fnut.2021.678105/full).

Wrap Up
Mouth rinsing with a pink non-caloric, artificially sweetened solution improved self-selected running speed and distance covered by 4.4% compared to rinsing with an isocaloric, taste-matched clear solution.

Heart rate and feelings of arousal were unaffected by mouth rinse color, yet feelings of pleasure increased by about 12% with the pink mouth rinse, which may have bolstered the performance improvement.

I hope you're feeling in the pink. Thanks for stopping by.

P.S.
Study of mouth rinsing with pink solution in Frontiers in Nutrition journal: www.frontiersin.org/articles/10.3389/fnut.2021.678105/full
Article on study on EurekAlert! website: www.eurekalert.org/pub_releases/2021-05/uow-pdc051021.php

Household Chores Help Brain

Welcome back. Nine years ago, in a blog post Vacuuming with Cats, I wrote:

[M]y wife takes the lead on fix-it chores in our household. If, instead of cheering “Go, Girl!” you bemoan the lot of the harried wife who, even in this modern age, must still do it all, please search for my older blog posts on laundry and food shopping. You’ll learn that I handle those chores. In fact, in my very first post, I mentioned that I also do the cleaning…This accounting isn’t to seek acclaim or refocus the target of your bemoaning; it’s only so I may get to vacuuming.

Warren’s cleaning tools…well, most of them.

Forgive my reminiscing. I just wanted to explain why there’s a very good chance I have increased the volume of my brain. Oh, sorry again. I should have mentioned a study by researchers affiliated with Canada’s Rotman Research Institute, the Toronto Rehabilitation Institute and the University of Toronto. They found that time spent engaging in household physical activity was positively associated with brain volume in older adults.

May I tell you how they came to that conclusion?

Looking at Physical Activity and Brain Health
It’s well documented that physical activity, especially recreational, is positively associated with brain volume and cognition in older adults. What is less understood is the contribution of other daily activities. The researchers set out to identify associations among household physical activity, brain volume and cognition in older adults that were cognitively unimpaired and free from significant medical, neurological or psychiatric conditions.

Screening of potential study participants included telephoned demographic, medical and cognitive questions in addition to three hospital visits for a health evaluation, cognitive assessment and structural brain imaging (acquired with a Siemens Trio 3T MRI Scanner).

Sixty-six participants were selected (ages 65 to 83; 62% female) and further assessed using Phone-FITT, a telephone questionnaire for collecting information from older adults on the frequency, duration and intensity (based on breathing) of all physical activities performed over the past month. (The questionnaire's developers note that intensity measures tend to decrease response reliability and might be omitted, which the researchers did.)

Phone-FITT accounts for season, allows reporting of activities not specifically listed and categorizes household apart from recreational physical activities. Household physical activity includes light housework (tidying, dusting), meal preparation and clean up, shopping, heavy housework, home maintenance (yard work, home repairs) and care giving.

Analyzing the Data
The researchers extracted estimates of the volumes of intracranial, whole brain, gray matter, white matter, hippocampal and frontal lobe from the structural images of each participant’s head. To account for head size variability, brain volumetric measures were adjusted for intracranial volume.

Brain cross-section, showing gray matter and white matter
(difference.guru/difference-between-white-and-gray-matter/).

Cognitive performance was assessed in four domains: memory, working memory/attention, processing speed and executive function.

Associations among physical activity (household and recreational), brain volume and cognition were investigated with statistical modeling, adjusting for age, gender, Framingham Risk score (estimates 10-year cardiovascular risk) and either intracranial volume or education. Additional analyses examined significant results and associations with hippocampal and frontal lobe volume.

Wrap Up
The study found household, but not recreational, physical activity was positively associated with brain volume measurements, especially gray matter volume. In contrast, no significant associations were observed between household or recreational physical activity and cognition.

Key differences between brain gray matter and white matter (www.developinghumanbrain.org/ graphic modified from www.pinterest.de/pin/457959855860455384/).

The researchers posited that the lack of association between recreational physical activity and brain health indicators could be attributed to the removal of Phone-FITT intensity from the analysis, which might also explain the lack of association with white matter volume.

Above all, the study highlighted the brain benefits associated with household chores and may motivate older adults to be more active by providing a more sustainable, low risk form of physical activity.

Please don’t inquire if I can assist with cleaning. I already have enough to benefit my brain. Many thanks for stopping by.

P.S.
Study of household physical activity and brain volume in BMC Geriatrics journal: bmcgeriatr.biomedcentral.com/articles/10.1186/s12877-021-02054-8
Article on study on EurekAlert! website: eurekalert.org/pub_releases/2021-04/bcfg-sto041521.php
Phone-FITT reference: journals.humankinetics.com/view/journals/japa/16/3/article-p292.xml
Brain size and volume background: en.wikipedia.org/wiki/Neuroscience_and_intelligence

Skip Mouthwash After Exercise

Welcome back. You might recall my blog post Salt in Mind. Though I wrote about my dislike of salty food, the takeaway was salt’s link with increased risk of dementia and diseases of the brain and blood vessels, at least in mice.

Salt was being blamed because a study found: [E]xcess salt suppressed functioning of cells lining blood vessels to the brain (endothelial cells). This caused a reduction of nitric oxide, a gas the cells produce to relax the blood vessels and increase blood flow.
 

Reading blood pressure (from
www.cdc.gov/features/blood-pressure-tips/index.html).

OK, so what has this got to do with mouthwash and exercise, the subject of this post? I’m going to tell you. Just don’t forget that nitric oxide relaxes blood vessels and increases blood flow. In other words, it affects blood pressure. 

Post-Exercise Hypotension
International collaborators led by an investigator from the UK’s University of Plymouth conducted a study that demonstrated the importance of oral bacteria in cardiovascular health.

Their work built upon earlier research that showed exercise reduces blood pressure. How? Exercise produces nitric oxide, which (as you know) dilates blood vessels (“vasodilation”), increasing blood flow to active muscles.

The question addressed by the recent study was how blood circulation stays higher after exercise--how does exercise cause a blood-pressure lowering response known as post-exercise hypotension?

Nitric Oxide, Nitrate, Nitrite, Nitric Oxide
To answer the question, the investigators focused on nitric oxide and a compound that nitric oxide degrades to, nitrate.

Nitrate was of interest because research has shown it can be absorbed in the salivary glands and excreted with saliva in the mouth. Some species of oral bacteria can use the nitrate and convert it into nitrite.

If it seems we’re going in circles, we are. When the nitrite in saliva is swallowed, it’s partly absorbed into the circulation and reduced to nitric oxide, which could be responsible for post-exercise hypotension.

Testing the Importance of Oral Bacteria
How could the researchers prove this? By interfering with the oral bacteria. If those critters don’t convert nitrate to nitrite, blood circulation won’t stay higher and blood pressure lower after exercising.

In two separate sessions, the researchers had 23 healthy adults run on a treadmill for 30 minutes, then be monitored at rest for two hours. Only water was allowed during exercise and recovery.

Blood pressure was measured before exercise and at 1 hour and 2 hours after exercise. To analyze nitrate and nitrite concentrations and oral bacteria, other testing included blood and salivary samples taken before and 2 hours after exercise. 

Mouthwash and exercise,
here with my stationary bike
rather than a treadmill.

To gauge the importance of oral bacteria, the runners rinsed their mouths periodically during the recovery with either an antibacterial mouthwash (0.2% chlorhexidine) or a placebo of mint-flavored water.

The Mouthwash Effect
The study found that rinsing with antibacterial mouthwash after exercise reduced the  blood-pressure lowering effect by 61% at 1 hour into the recovery period and completely by 2 hours.

In contrast, the average blood pressure of participants that rinsed with the placebo remained lower than the baseline throughout the 2-hour recovery period.

Supporting the researchers’ expectation, the measured levels of circulatory nitrite at 2 hours after exercise increased for participants that rinsed with the placebo and remained constant for those that rinsed with the antibacterial mouthwash.
 
Wrap Up
The researchers concluded that nitrite synthesis by oral bacteria is a key mechanism to induce the vascular response to exercise over the first period of recovery thereby promoting lower blood pressure and greater muscle oxygenation.

Though I stand by my earlier comments on the virtues of antibacterial mouthwash to control the evil tooth decay-causing micro-creatures that slosh around in your mouth (Dental Check-Up Time), you may want to adjust the timing of your rinse. Thanks for stopping by.

P.S.
Study of mouthwash and post-exercise hypotension in Free Radical Biology and Medicine journal: www.sciencedirect.com/science/article/abs/pii/S0891584919307610
Example articles on study:
www.eurekalert.org/pub_releases/2019-09/uop-muc090319.php
www.sciencealert.com/a-strange-thing-happens-if-you-use-mouthwash-after-you-exercise

Thermally Responsive Fabric

Never mind cotton. Forget wool. Skip those high-tech, wicking polyesters. Have I got a fabric for you. Well, I don’t, but researchers from the University of Maryland do.

Welcome back. I thought you’d be interested to learn about this new fabric, even if it’s not quite ready for market. In short, the fabric is thermally responsive. It automatically responds to the temperature and humidity of our skin to either release or trap heat.

I could stop there, but I’ll continue for those in disbelief or who just want to learn more. Since the fabric’s ability to regulate the heat exchange is tied to infrared radiation, I’ll start there.

Infrared Radiation and Our Bodies
In a blog post several years ago, I illustrated the use of thermal sensing in medical imaging (Thermal Body Mapping Addendum).

Thermal images, where colors correspond to temperature differences, have been used to assess the effects of stress on hands of patients with different medical conditions or injuries (from iopscience.iop.org/0967-3334/33/3/R33/article).

As I wrote at the time, thermal imaging should at least be of value where dissipation of heat through the skin is diagnostic. Here’s what that was all about.

Photographic cameras collect radiation that we see. Thermal sensors collect radiation in the infrared (IR) region, which is beyond the sensitivity of our eyes. IR radiation covers a broad spectrum of wavelengths. Thermal sensors normally collect IR radiation at longer wavelengths, where the level of radiation is related to the temperature of the object sensed. In general, the hotter the object, the more IR radiation it emits.

The principal way our bodies lose (emit) and gain (absorb) heat is through IR radiation, and our skin is a very efficient emitter and absorber of IR radiation. If we’re cold, we add clothes to reduce the transmission of IR radiation; if we’re warm, we remove clothes to promote the transmission of IR radiation. The newly developed fabric does both.

How the Fabric Works
For the new fabric, the researchers took fibers of two different synthetic components, one that absorbs water, the other that repels it. They coated the fibers with a thin layer of carbon nanotubes (lightweight, carbon-based, conductive metal).

Because the coated fibers both absorb and repel water, the fabric warps when exposed to humidity such as from a sweating body. That distortion opens pores in the fabric, allowing heat to escape.

Of greater consequence, the distortion brings the coated fibers closer together. That modifies the electromagnetic coupling between neighboring fibers, changing the way the fabric interacts with IR radiation. Depending on the tuning, the fabric will either allow IR radiation to pass or block it almost instantaneously. 

Thermally responsive fabric (photo by Faye Levine from today.umd.edu/articles/hot-and-cold-comfort-a77c4599-3bb4-4efd-83d2-79ac418ad018).

Wrap Up
The researchers report that the new fabric effectively modulated the IR radiation by over 35% as the relative humidity of the underlying skin changed.

They note that, while more work is required before we’ll see clothes of the new fabric, the materials are readily available. The carbon nanotube coating can be added easily during the dyeing process. And yes, the fabric can be knitted, dyed and washed like other sportswear fabrics. So, get ready.

Thanks for stopping by.

P.S.
Study of new fabric in Science: science.sciencemag.org/content/363/6427/619
Example articles on study:
www.newscientist.com/article/2193057-heat-sensitive-fabric-cools-you-on-hot-days-and-warms-you-in-the-cold/
www.sciencedaily.com/releases/2019/02/190207142242.htm
www.apparelnews.net/news/2019/feb/21/university-maryland-researchers-create-fabric-envi/
Example article on infrared radiation and our bodies: www.health.belgium.be/en/interaction-between-radiation-and-human-body

A version of this blog post appeared earlier on www.warrensnotice.com.

Bike at Your Desk

U.S. Department of Health
and Human Services’ 2nd
Edition of Physical Activity
Guidelines for Americans.

Welcome back. In case you missed it, the U.S. Department of Health and Human Services released the second edition of its Physical Activity Guidelines for Americans. There’s a summary of the 117-page report in the Journal of the American Medical Association (JAMA).

Physical Activity Guidelines
Like the first edition, published in 2008, the report’s overriding message is that regular physical activity has health benefits for everyone, regardless of age, gender, race, ethnicity or body size.

Guidance on the types and amounts of physical activity to improve health outcomes is provided for preschool-aged children to older adults, with a section for pregnant and postpartum women and adults with chronic conditions or disabilities.

To encourage and be accommodating the key guidelines for adults opens with: Adults should move more and sit less throughout the day. Some physical activity is better than none.

Which brings me to the main topic of this blog post: a pilot study from the University of Massachusetts, Amherst. The researchers compared the metabolic and work-skill effects of pedaling, while sitting at a pedal desk, with those of just sitting at a standard office desk.

Pedal Desks
Different configurations of pedal or bike desks or detached under-desk peddlers have been around for several years. They’ve found principal acceptance occupying fidgeting students in K-12 classrooms, but along with standing desks and treadmill desks, they’re making inroads in other venues. 

Under-desk peddlers in a North Carolina middle-school classroom, 2016 (from www.thisisinsider.com/teacher-bike-pedals-desks-concentration-2016-9).

A bicycle desk (from
www.lifespanfitness.com).

The study was undertaken because desks configured with a seated pedal apparatus could be an important tool for reducing workplace inactivity. This is especially the case since pedal desks are self-paced, relatively easy to use by workers with existing musculoskeletal problems or reduced mobility, oriented toward non–weight-bearing activities and minimally disruptive.

Pedal Desk Study Design

Twelve overweight or obese, sedentary office workers (6 men, 6 women, age 21 to 64) were tested in two conditions at least six days apart: (1) seated at a pedal desk, pedaling at a self-selected, light-intensity pace for 2 hours and (2) seated at a conventional workstation for 2 hours. 

Prototype pedal desk
used for pilot study
(see P.S. link to study).

At both test sessions, participants rested for 20 minutes and had an intravenous catheter inserted for blood sampling. After baseline fasting sample collection, the participants were given a standardized meal (cornflakes, heavy cream and whole milk) to be consumed over a 10-minute period.

Blood samples for glucose, insulin and free fatty acid concentrations were collected every 15 minutes during the remainder of the post-meal test while participants performed scripted computer-based work tasks (Stroop test, mouse proficiency test, choice reaction, typing and reading comprehension).

Pedal Desk vs. Standard Desk
The study found the participants’ use of the pedal desk required significantly less insulin to maintain glucose concentrations than did their use of the standard desk. There were no significant changes in plasma glucose and free-fatty acid concentrations with the pedal desk at any observed time.

In addition, the only significant difference in work skills measurements was a slower mouse-clicking response with the pedal desk; however, the average difference was only 2.2 seconds over approximately 1 minute of testing.

Wrap Up

Kiosk for pedaling to self-power
electrical devices (from wewatt.com/).

Although the study results are based on only 12 participants, the lower post-meal insulin concentrations with no negative impact on work skills suggest that use of a pedal desk could help achieve public and occupational health goals in sedentary work environments.

And there’s another potential benefit. All that pedaling could be used to produce some amount of electrical power. In fact, CNET featured a company that was seeking Kickstarter funding to pursue that goal in 2013, and at least one company is now marketing power-generating bike desks and sustainable office kiosks.

Pedal desks in elementary school classroom—note the blurry pedaling feet (from www.youthfit.com/kinesthetic-classroom/pedal-desks).

Who knows? Perhaps those fidgeting grade-school kids could keep the whole school lit up. Thanks for stopping by.

P.S.
Physical Activity Guidelines for Americans. 2nd ed.: health.gov/paguidelines/second-edition/pdf/Physical_Activity_Guidelines_2nd_edition.pdf
Guidelines summary in JAMA: jamanetwork.com/journals/jama/fullarticle/2712935
Pilot study of pedal desks in Medicine & Science in Sports & Exercise journal: insights.ovid.com/crossref?an=00005768-201810000-00021
Article on study on ScienceDaily website: www.sciencedaily.com/releases/2018/11/181108130511.htm
CNET article on generating power from pedal bikes: www.cnet.com/news/pedal-power-pedal-your-desk-to-power-your-laptop/

A version of this blog post appeared earlier on www.warrensnotice.com.

Reducing Age-Related Language Decline

Wait! Wait! I know what it is.
It’s on the tip of my tongue
(from www.barcelonareview.com/36/e_quizans.htm).

Welcome back. Do you ever experience tip-of-the-tongue lapses, when you just can’t recall a word you know? By the time you reach my age, you’ve learned so many words, it can be difficult to remember them all as quickly as you’d like; but there’s more to it.

An international team led by researchers from the UK’s University of Birmingham demonstrated that, while cognitive abilities decline with age, aerobic fitness can reduce those tip-of-the-tongue occurrences.

Before describing the study, I’d better point out that tip-of-the-tongue states are not a memory problem; they’re not associated with memory loss. They indicate a disruption in the two-stage process of retrieving the word meaning and phonology (sound form representations).

Relating Aerobic Fitness to Tip-of-the-Tongue States

Participants
To investigate the relationship between aerobic fitness and tip-of-the-tongue states, the researchers had 28 healthy older adults (20 women, mean age 70; 8 men, mean age 68) complete an aerobic fitness test and a language experiment, and 27 university students (19 women, mean age 23; 8 men, mean age 23) complete the language experiment only.

Aerobic Fitness Test
To measure aerobic fitness, the older participants did stationary cycling (a graded, sub-maximal aerobic fitness test on a cycle ergometer) to estimate maximal oxygen consumption (VO2max, where V - volume, O2 - oxygen). VO2max is the maximum amount of oxygen a person can utilize during intense exercise.

Language Experiment
For the language experiment, young and old participants completed the same computer-based, definition-filling task. The participants were presented 60 definitions or questions in random order (20 definitions of low frequency words, 20 definitions of easy words and 20 questions about famous people). 

Example definitions, target words and foils if participants experienced a tip-of-the-tongue (from www.ncbi.nlm.nih.gov/pmc/articles/PMC5928071/).

The definitions and questions remained on screen until the participants responded that they knew the target word, did not know the target word or had a tip-of-the-tongue experience. (The instructions read: “Usually we are sure if we know or don’t know a word. However, sometimes we feel sure we know a word but are unable to think of it. This is known as a ‘tip-of-the-tongue’ experience.”)

If participants indicated they experienced a tip-of-the-tongue state, they were asked to provide three pieces of information about its sound: (1) the initial letter or sound; (2) the final letter or sound and (3) the number of syllables. Finally, participants were asked to select the target word from a list of four words displayed on the screen or to indicate that the word they were thinking of was not in the list.

The data were analyzed using mixed effects models, an extension of linear regression models. In addition to comparing older with younger participants, the researchers performed a median split on the standardized aerobic fitness scores to generate a high-fit older adults group and a low-fit older adults group.

Results
The key findings were that older adults experienced more tip-of-the-tongue occurrences and had less access to phonological information than did the younger participants; however, the more aerobically fit the older adults were, the less likely they were to experience a tip-of-the-tongue state.

The probability that older adults experienced a tip-of-the-tongue decreased as aerobic fitness increased (from www.ncbi.nlm.nih.gov/pmc/articles/PMC5928071/).

The tip-of-the-tongue occurrence of high-fit older adults was lower than that of low-fit older adults and not much higher than that of young adults.

Tip-of-the-tongue occurrences of young, high-fit elderly and low-fit elderly participants on language experiment; error bars represent standard error of the mean (from www.ncbi.nlm.nih.gov/pmc/articles/PMC5928071/).

The study also found that young and older adults both experienced fewer tip-of-the-tongue occurrences the shorter the target words (as measured by the number of phonemes) and the larger their vocabulary size. Notably, older adults had a significantly larger vocabulary than young participants.

Wrap Up
Overall, the study demonstrated that there is a relationship between language production abilities and aerobic fitness in healthy older adults. The higher the older adults’ aerobic fitness level, the lower the probability of experiencing a tip-of-the-tongue. The results further support increased physical activity for healthy aging and optimal brain function across the life span. Go for it!

Thanks for stopping by.

P.S.
Study of aerobic fitness and language decline in Scientific Reports journal: www.ncbi.nlm.nih.gov/pmc/articles/PMC5928071/
Article on study on Berkeley Wellness website: www.berkeleywellness.com/healthy-mind/memory/article/tip-tongue-lapses-eased-exercise?s=EFA_181020_AA1&st=email&ap=ed

A version of this blog post appeared earlier on www.warrensnotice.com.

Kids vs. Endurance Athletes

Energizer Bunny (from
www.energizer.com/energizer-bunny).

Welcome back. Today’s blog post is dedicated to the parents of all those young Energizer Bunnies that just keep going and going and going.

A study by collaborating researchers from France’s Clermont-Auvergne University, Australia’s Edith Cowan University and the French Rowing Federation found that, exercise-wise, young children are on par with endurance athletes.

Test Participants
The researchers tested three groups of volunteers: 12 boys, age 8 to 12; 13 endurance-trained male athletes, age 19 to 27; and 12 untrained men, age 19 to 23.

To be included, the boys and untrained men had to be healthy but spending no more than 4 hours per week performing recreational physical activity, with neither aerobic training nor vigorous physical activity. The athletes were national-level competitors (long-distance runners, cyclists, triathletes), engaged in long distance physical activities at least 6 times per week for at least 2 years.

The boys were prepubescent based on somatic maturity, which was assessed using age from peak height velocity (the period where maximum rate of growth occurs) and determined from height, sitting height and body mass.

Two Experimental Sessions
Each volunteer was tested in two experimental sessions at least 48 hours apart to obtain measures of the two ways their bodies produce energy--aerobic, using oxygen from the blood, and anaerobic, which produces acidosis and lactate.

Cyclus 2 ergometer used for
Wingate cycle test (from
www.cyclus2.com/en/the-ergometer.htm).

During the first session, the researchers evaluated body characteristics and composition, somatic maturity and the power at maximum oxygen uptake. Also, the volunteers had to perform two short sprints on a cycle ergometer with a prescribed resistance.

During the second session, the volunteers performed the commonly employed Wingate cycle test to determine the maximal anaerobic power, fatigue rate, relative (net) energy contribution derived from oxidative metabolism and the post-exercise recovery rates of blood lactate concentration, heart rate and oxygen uptake.

Experimental Results
The results showed that untrained adults fatigued much more than the boys, whose net contribution of energy derived from aerobic metabolism and rate of fatigue were similar to that of the endurance athletes.

The boys’ post-exercise recovery of oxygen uptake and heart rates were respectively similar to and faster than those of the endurance athletes. The removal ability of lactate from the blood compartment was also higher in the boys than in the athletes, which could explain why the boys’ rate and magnitude of fatigue were similar to the athletes and why the boys recovered faster from high-intensity exercise.

Recovery of net heart rate (peak – baseline) as % of initial value after Wingate test in children, untrained adults and athletes (stars, dollar signs and section signs refer to levels of significance between values) (from www.frontiersin.org/articles/10.3389/fphys.2018.00387/full).

Wrap Up
Overall, the study found that, physiologically, prepubescent boys could be considered comparable to well-trained, adult male endurance athletes, despite having a lower work capacity. While the results seem clear, I would think it useful to repeat the study with a larger number of participants and females.

Based on the study results, the researchers note that prepubescent children may not need specific training to develop their aerobic metabolic competence. Other strategies they suggest to improve exercise performance include anaerobic exercises and movement technique training to improve mechanical efficiency.

Given that maturation and growth processes adversely affect oxidative energy production in exercising muscle, they advise that aerobic training may be a priority in pubescent and post-pubescent children to maintain their aerobic potential and delay development of exercise-induced fatigue.

Sorry, there’s no advice for how parents can keep up. Thanks for stopping by.

P.S.
Exercise study comparing children with adults in Frontiers in Physiology journal: www.frontiersin.org/articles/10.3389/fphys.2018.00387/full
Article on study on ScienceDaily website: www.sciencedaily.com/releases/2018/04/180424083907.htm
Somatic maturity assessment used in study from Medicine & Science in Sports & Exercise journal: journals.lww.com/acsm-msse/Fulltext/2002/04000/An_assessment_of_maturity_from_anthropometric.20.aspx
General background from Wikipedia:
- Wingate cycle test: en.wikipedia.org/wiki/Wingate_test
- Aerobic exercise: en.wikipedia.org/wiki/Aerobic_exercise
- Anaerobic exercise: en.wikipedia.org/wiki/Anaerobic_exercise

A version of this blog post appeared earlier on www.warrensnotice.com.

Dance Versus Fitness Training

Welcome back. Vicki and I danced at a wedding in August. We hadn’t danced in years, at least I hadn’t. A year or two ago, she confessed that George had her doing the polka when they were alone in the shop, after he made the coffee for the Saturday morning coffee klatch. George is about 90, and he makes phenomenal matchstick structures when he isn’t making coffee or dancing the polka.

Growing up, before and through high school, I was not a good dancer. I never learned how to jitterbug or whatever we called it. And though I liked slow dancing, as I learned repeatedly through life, I wasn’t cut out to be a leader.

I metamorphosed in college when the twist, jerk, mashed potato and other non-contact dances swept the country in the early 1960s. Freedom of expression! Who needed a partner? I became a very good dancer.  

Uma Thurman and John Travolta doing the twist plus a few other dances in Tarantino’s 1994 film Pulp Fiction. (Photo from video: www.youtube.com/watch?v=Ik-RsDGPI5Y)

All this personal history is going somewhere, of course. As you might expect even if you missed the blog post title, I happened upon a recent study about dancing. This one compared the anti-aging effects of dance training with those of fitness training. Guess which was better for healthy seniors. A little brain science will help.

The Hippocampus
The brain’s hippocampus is key to memory, learning and spatial navigation. Although the hippocampus is affected by normal and pathological (e.g., Alzheimer’s) aging, it’s one of the few brain regions that can generate new neurons throughout our lives. Producing those new neurons might help to slow cognitive losses.

How can we do that? Exercise is one way. Research has shown higher cardiorespiratory fitness levels are associated with larger volumes of the hippocampus in late adulthood, and larger hippocampal volumes may, in turn, contribute to better memory function.

Independent of cardiorespiratory fitness, motor skill learning and motor fitness that come with dancing can also affect hippocampal volume.

Study Parameters
A team of scientists led by researchers from the German Center for Neurodegenerative Diseases set out to compare how dance and fitness training affect the volumes of the hippocampus and hippocampal subfields and, in addition, balance.

The researchers screened and assigned 52 volunteers to either an experimental dance group or a traditional fitness group. After 18 months of training, only half of the volunteers remained, 14 in the dance group and 12 in the fitness group. Those who completed the training did not differ significantly in age (average 68), gender, body mass index or education.

The fitness training followed recommended health sport guidelines and addressed endurance, strength-endurance and flexibility. The dance training included both permanent and changing choreographies, focusing on turns, head-spins, shifts of center of gravity, single-leg stances, skips, hops and different dance steps to challenge the balance system. 

For the first six months, training for both groups lasted 90 minutes, twice a week. That had to be reduced to once a week for the last 12 months.

Pre- and post-training measures of hippocampal subfield volumes were derived from magnetic resonance images. Those for balance were obtained with the Sensory Organization Test, which assesses the three sensory systems--somatosensory, visual, and vestibular.

Shall We Dance or Work Out?
Insofar as the hippocampus volume is linked to memory and learning, dance training was shown to be at least as beneficial as fitness training for slowing cognitive losses. Beyond that, the study found that dance training excelled for improving balance.

Dance and fitness training both led to increases in hippocampal subfield volumes; however, the dancers showed volume increases in more subfields. Further, only the dancers showed an increased balance composite score, improving in all three sensory systems.

Wrap Up
Vicki and I should probably start dancing again (not the polka), though I doubt I could handle the dance training given in the study. That seemed rather intense, more like brain training. I would just want to dance, not think too much about it and take whatever anti-aging effects I can get. Thanks for stopping by.

The bride and bride’s father dance with freedom of expression at a wedding Rachel photographed. (www.rachelphilipson.com)

P.S.
Dance vs fitness training study in Frontiers in Human Neuroscience journal: http://journal.frontiersin.org/article/10.3389/fnhum.2017.00305/full
Article on study on ScienceDaily website: www.sciencedaily.com/releases/2017/08/170825124902.htm
Example of earlier article on dancing versus exercise: www.hss.edu/newsroom_health-benefits-dance-fitness-trend-dancing-with-the-stars.asp