Category: Exercise

Categories : COVID ExerciseTags :

Lower COVID Risk in Men Physically Fit When Young

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Many Swedish men who were physically fit when they did their military service were able to avoid being hospitalised when they became infected with COVID up to 50 years later. 

The results of the study by University of Gothenburg researchers are now available in the BMJ Open.

Sweden has a system of military conscription for its citizens, which it reinstated in 2017 and expanded to include women. The study drew on the Swedish Conscription Register, which contains data on over 1.5 million young Swedish men who began their military service in the years 1969–2005. Nearly all of these men then underwent both a bicycle test and a strength test. In spring 2020, some 2500 of the men included in the Conscription Register were hospitalised with COVID.

The men were divided into three groups based on their results in the fitness and strength tests, and their data were merged with three other Swedish registers: the National Inpatient Register (IPR, also known as the Hospital Discharge Register), Intensive Care Register, and Cause of Death Register. Analysis showed a clear link between fitness and strength in youth and the risk COVID hospitalisation 15–50 years after conscription.

Lead author Agnes af Geijerstam, PhD Student, University of Gothenburg’s Sahlgrenska Academy said, “At the population level, we can see that both good fitness and good muscle strength in the late teens are protective factors for severe COVID. For those with good fitness at the time of conscription, the risk of dying in spring 2020 was half as high as for the least fit. For those whose strength was good back then, too, we see a similar protective effect.”

However, since the oldest men in the study had not reached age 70, COVID deaths were uncommon in the study.

“Previous studies have shown that obesity is a risk factor for severe COVID. But we see that good fitness and strength are protective factors for everyone, including men with overweight or obesity,” said Professor Lauren Lissner, senior coauthor of the study.

Moreover, the study showed a link between the men’s height to the risk of COVID-19 infection.

“The taller the men were, the greater their risk of needing advanced care when they had gotten COVID; but per centimeter this increase in risk is very small. Also, unlike fitness and strength, there is no way to influence our height” af Geijerstam says.

Many studies have already demonstrated the protective effect of good physical fitness in numerous medical conditions, including infections. It has been established that physical activity strengthens the immune system and reduces inflammation propensity. Fitness during adolescence is also likely to be associated with active and otherwise healthy lifestyles throughout adult life.

“It’s interesting to see that the high fitness and strength levels those men had so many years ago can be linked to protection against severe COVID. Today, young people are becoming ever more sedentary, and that means there’s a risk of major problems arising in the long term — including a reduced resistance to future viral pandemics. Children and adolescents must get ample scope to move around,” af Geijerstam said.

Source: University of Gothenburg

Journal information: af Geijerstam, A., et al. (2021) Fitness, strength and severity of COVID-19: a prospective register study of 1 559 187 Swedish conscripts. BMJ Open. doi.org/10.1136/bmjopen-2021-051316.

Categories : ExerciseTags :

Intense Training Results in Temporary Mitochondrial Impairment

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Photo by Quino Al on Unsplash

Elite athletes have temporary mitochondrial impairment following intense workouts, according to new research, which suggests they may need to be mindful about overtraining. 

Mitochondria are organelles that are responsible for most of the useful energy derived from the breakdown of carbohydrates and fatty acids, which is converted to ATP by the process of oxidative phosphorylation. Mitochondrial capacity is a term used to describe the body’s ability to generate energy, and is one factor associated with increased athletic performance during endurance exercise. Previous research found that untrained recreational athletes had a decrease in mitochondrial capacity after sprinting exercises.

In this study, the researchers worked with a small group of male elite athletes, many of whom were national title holders or had international recognition for their performance in cycling and triathlon. The athletes participated in a four-week training programme in their primary sport, which consisted of two to four days of low-to-moderate–intensity endurance workouts, followed by three days of more intense training. These intense workouts included high-intensity interval training in the morning, followed by a seven-hour break and then a moderate-intensity cycling session in the afternoon. Each volunteer did between 12 and 20 hours of activity per week. The athletes, though used to heavy training, were not accustomed to this specific workout schedule.

The researchers were surprised to observe that the highly trained participants’ mitochondrial capacity was impaired after the month-long training period. “We thought that elite athletes should be more resistant against [these] kind of alterations,” said Filip Larsen, PhD, of the Swedish School of Sport and Health Sciences and corresponding author of the study.

However, elite athletes may be able to prevent temporary mitochondrial impairment by listening to their bodies, the researchers suggested. By paying attention to changes such as “mood disturbances, reductions in maximal heart rate [during exercise] and muscles that feel heavy and unresponsive” top athletes may be able to pull back and avoid overtraining situations that could contribute to reduced mitochondrial content and function, Larsen explained. “Exercise is good for you, but too much unaccustomed training might have mitochondrial consequences.”

The study also found that reduced mitochondrial capacity did not affect exercise performance, suggesting that oxygen delivery from the heart to the muscles plays a more important role than mitochondrial function in performance. Expression of three proteins with strong antioxidant properties were also found to be increased in the muscles after intense training.

Source: American Physiological Society

Journal information: Daniele A. Cardinale et al, Short term intensified training temporarily impairs mitochondrial respiratory capacity in elite endurance athletes, Journal of Applied Physiology (2021). DOI: 10.1152/japplphysiol.00829.2020

Categories : Exercise GenderTags :

Having No Audience Slows Male Athletes but Boosts Females

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Source: Andrea Piacquadio on Pexels


Researchers have found that having no audience present made men run slower, but helped women run faster.

The new study by Martin Luther University Halle-Wittenberg (MLU) examined the effect of an audience on performance of athletes at the 2020 Biathlon World Cup. According to the new analysis, women also performed better in complex tasks, such as shooting, when an audience was present while men did not.

According to social facilitation theory, a person’s performance is impacted if other people watch them. Merely having an audience improves the performance of simple tasks, especially those requiring stamina: and it is surprisingly hard to circumvent. One study showed that ‘virtual’ bystanders did not have the same effect as having real bystanders in firefighter’s performance in training tasks.

“The studies have been relatively clear so far, but the results are more heterogeneous when it comes to more complex coordinative tasks,” explains Amelie Heinrich from the Institute of Sports Science at MLU. Generally the assumption is that performance tends to drop when an audience is present.

Heinrich is a sports psychology expert who coaches Germany’s junior biathlon squad, and took advantage of the unique conditions created by COVID. “The pandemic offers a unique opportunity to study an audience’s influence outside of experimental conditions in the real world,” said Heinrich, who compared the running times and shooting successes of male and female biathletes from the 2018/2019 season with their performances in the 2020 season in the sprint and mass start events.

“The men’s results were as expected: they ran faster with an audience present, but performed more poorly in shooting,” noted Heinrich. Cross-country skiing mainly requires stamina while shooting is a coordinative task. 

“Interestingly, it was the other way around for women.” With spectators present they ran slower, but on average, it took them an entire second less to make their shot and, at least in the sprint, their scoring performance was five per cent higher. The researchers argue that it is not just due to fluctuation in the athletes’ performance; with 83 (sprint) and 34 (mass start) World Cup biathletes, the study has a good basis for evidence, and the same tendency was seen in both disciplines.

“To our knowledge, this is the first time that a study was able to show a different effect of the audience on men and women,” noted Professor Oliver Stoll, head of the sports psychology section at MLU. Most previous research focused on men. “Our study raises questions about the generalisability of the social facilitation theory and indicates there might be a previously unknown difference between men and women,” said Heinrich, adding that more research in sports with coordination and stamina is needed.

Thus far, the researchers can only speculate about the reasons for the possible gender-specific performance differences in response to audiences or the lack of. “It is possible that gender-specific stereotypes play a role,” said Heinrich. Men have a stereotype that they should be strong, while studies have shown that women are more sensitive to feedback. In any case, Heinrich concluded, this underscores the need to account for gender in studying psychological effects.

Source: Martin-Luther-Universität Halle-Wittenberg

Journal information: Heinrich A. et al. Selection bias in social facilitation theory? Audience effects on elite biathletes’ performance are gender-specific. Psychology of Sports and Exercise (2021). Doi: 10.1016/j.psychsport.2021.101943

Categories : Exercise Neurodegenerative DiseasesTags :

Lifestyle Changes Shown to Reduce Risk of Dementia

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Photo by Ketut Subiyanto from Pexels

After almost two decades, a new drug for Alzheimer’s disease has been approved in the US. However, some experts say it doesn’t really work — only treating amyloid plaques which are thought to cause the disease — and worry that it may cost a lot.

The amount of attention around this news reflects the importance of preventing dementia, with its devastating toll on families and patients. But millions of adults could lower their chances of needing such a drug by taking preventative measures.

That’s why a national panel of experts including the University of Michigan’s Deborah Levine, MD, MPH, recently published a guide for primary care providers on this topic as an official Scientific Statement from the American Heart Association.

People dread Alzheimer’s disease, she said. Helping people understand that they can prevent or slow future dementia by taking specific steps now could motivate them to increase their healthy behaviours for a positive effect.

The first step is to recognise that dementia risk is higher among people with seven major modifiable risk factors.

These are: depression, hypertension, physical inactivity, diabetes, obesity, hyperlipidaemia, poor diet, smoking, social isolation, excessive alcohol use, sleep disorders and hearing loss. Addressing each of these factors can, to varying extents, help reduce the risk of developing dementia, a fact backed by decades of research.

The second step is using medication, lifestyle change and other interventions to help patients reduce their dementia risk.

“Dementia is not inevitable,” said Dr Levine, a primary care provider at the University of Michigan Health, part of Michigan Medicine. “Evidence is growing that people can better maintain brain health and prevent dementia by following healthy behaviours and controlling vascular risk factors.”

These strategies can help preserve cognitive function and lower risk for heart attacks and strokes, said Dr Levine, who heads the Cognitive Health Services Research Program and sees patients at the Frankel Cardiovascular Center.

“We need to address the significant disparities that lead women, Black, Hispanic and less-educated Americans to have a much higher risk of dementia,” said Levine, a member of the U-M Institute for Healthcare Policy and Innovation.

She added that it’s never too late in life to start working on cognitive risk factor control.

“We have no treatments that will halt dementia – so it’s important to protect your brain health.”

Source: University of Michigan

Categories : Ageing Cardiovascular Disease ExerciseTags :

Tailored Heart Failure Rehabilitation Improves Outcomes

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An innovative early cardiac rehabilitation intervention customised for the individual improved physical function, frailty, quality of life, and depression in hospitalised heart failure patients. 

Photo from Olivier Collett on Unsplash

These findings were published  in the New England Journal of Medicine and also presented at the American College of Cardiology’s 70th Annual Scientific Session.  

“Designing earlier and more personalised individual-specific approaches to heart failure rehab shows great promise for improving outcomes for this common but complex condition that is one of the leading causes of hospitalisation for older adults,” said National Institute on Aging (NIA) Director Richard J Hodes, MD. “These results mark encouraging progress on a path to better overall quality of life and physical function for the millions of older Americans who develop heart failure each year.”

The study team was led by Dalane W Kitzman, MD, professor of cardiovascular medicine and geriatrics/gerontology at Wake Forest School of Medicine, Winston-Salem, North Carolina, and they followed 349 clinical trial participants with heart failure enrolled in “A Trial of Rehabilitation Therapy in Older Acute Heart Failure Patients” (REHAB-HF). On average, participants had five comorbidities that reduced of function — diabetes, obesity, high blood pressure, lung disease or kidney disease.

In an earlier pilot study, Kitzman and colleagues found striking deficits in strength, mobility and balance, along with the expected loss of endurance in older patients with acute heart failure, who were mostly fail or pre-fail. The team decided to focus on improving patients’ physical function, weakened already by chronic heart failure and age, and which was worsened by the traditional cardiac hospital experience involving lots of bedrest and resulting in loss of functions often persisting after discharge.

To address this. The REHAB-HF team designed earlier and more customised exercise programs focusing on improving balance, strength, mobility and endurance. They also began REHAB-HF during a patient’s hospital stay when possible rather than the usual six weeks post-discharge. After discharge, participants shifted to outpatient sessions three times per week for three months.

Compared to a control group getting usual cardiac rehab care, REHAB-HF participants showed significant gains in measures of physical functioning and overall quality of life, including tests for lower extremity function and mobility, and a six-minute walk test. Self-perception of their health status and depression improved in surveys compared to pre-trial baselines. Over 80% of REHAB-HF participants reported they were still doing their exercises six months after study completion.

“These findings will inform choices of heart failure rehabilitation strategies that could lead to better physical and emotional outcomes,” said Evan Hadley, M.D., director of NIA’s Division of Geriatrics and Clinical Gerontology. “Tailored interventions like REHAB-HF that target heart failure’s related decline in physical abilities can result in real overall benefits for patients.”

The study did not show significant differences in related clinical events including rates of hospital readmission for any reason or for heart-failure related rehospitalizations. The research team plans to further explore that and other issues through future expansions of REHAB-HF into larger and longer-term trials with broader participant subgroups.

Source: National Institute on Aging

Journal information: Kitzman et al. Rehabilitation Intervention in Older Patients with Acute Heart Failure with Preserved versus Reduced Ejection Fraction. New England Journal of Medicine. 2021 May 16 doi: 10.1056/NEJMoa2026141.

Categories : ExerciseTags :

Pink Drinks Make You Run Faster

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A new study led by the shows that sweetened pink drinks — purely as a result of their colour — can help people run faster and further compared to clear sweetened drinks.

The study, led by Centre for Nutraceuticals in the University of Westminster, found that a pink drink can raise exercise performance by 4.4% and can also bolster a ‘feel good’ effect, possibly making exercise seem less difficult. The findings were published in the journal Frontiers in Nutrition.

This marks the first investigation to assess the effect of drink colour on exercise performance and could open up a new avenue of future research in the field of sports drinks and exercise. Interest in colour and exercise performance had already resulted in studies, such as wearing red-coloured glasses during exercise which were found to raise testosterone but not performance.

The study involved asking participants to run on a treadmill for 30 minutes at a self-selected pace, ensuring a consistent exertion. Throughout the exercise they rinsed their mouths with either a pink artificially sweetened low-calorie drink or a clear drink which was also artificially sweetened and low-calorie.

The drinks were identical in every respect aside from the addition of pink colouration to the one. Pink was selected as it is associated with perceived sweetness, therefore increasing expectations of sugar and carbohydrate intake.

In prior research, it was found that rinsing the mouth with carbohydrates can improve exercise performance by reducing the perceived exercise intensity, so the researchers wanted to see whether rinsing with a pink drink with no carbohydrate stimulus could create a similar result through the placebo effect.

The results show that the participants ran an average 212 metres further with the pink drink while their mean speed during the exercise test also increased by 4.4 %. Feelings of pleasure were also improved, meaning participants found running more enjoyable.

Additional investigations will be needed to understand whether the proposed placebo effect causes a similar activation to the reward areas of the brain that are commonly reported when rinsing the mouth with carbohydrates. 

“The influence of colour on athletic performance has received interest previously, from its effect on a sportsperson’s kit to its impact on testosterone and muscular power,”  said corresponding author Dr Sanjoy Deb, University of Westminster. “Similarly, the role of colour in gastronomy has received widespread interest, with research published on how visual cues or colour can affect subsequent flavour perception when eating and drinking.

“The findings from our study combine the art of gastronomy with performance nutrition, as adding a pink colourant to an artificially sweetened solution not only enhanced the perception of sweetness, but also enhanced feelings of pleasure, self-selected running speed and distance covered during a run.”

Source: News-Medical.Net

Journal information: Brown, D. R., et al. (2021) Mouth Rinsing With a Pink Non-caloric, Artificially-Sweetened Solution Improves Self-Paced Running Performance and Feelings of Pleasure in Habitually Active Individuals. Frontiers in Nutrition. doi.org/10.3389/fnut.2021.678105.

Categories : Exercise General Interest Mental HealthTags :

Hiking Prescribed for Elderly Man Coping with Lockdown

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When Jim Snodgrass, 84, was expecting to receive medication to treat his anxiety, he instead was simply given the phone number for the Ramblers, a UK-based society of nature walkers and hikers.

Dr Victor Jack said that he recognised that Jim needed “social connection” and not medication. Hiking itself also has a number of proven physical and psychological health benefits. Some may be immediate, such as decreased blood pressure, decreased stress levels, enhanced immune system functioning, and restored attention, or else occur over time, such as weight loss, decreased depression, and overall wellness.

During the first COVID lockdown in March 2020, Jim was on his own since his wife Sheila died six years previously, said he suffered a breakdown.

The grandfather-of-two said: “I was not feeling good as I was bothered with my nerves so I called the doctor and that’s when I burst into tears on the phone to the receptionist.

“She was so nice to me and got the doctor to call me. I was surprised when he didn’t give me any pills and instead gave me the number for the Ramblers.”

During lockdown doctors could give exemptions to people who lived on their own to meet one other person outside. Then last summer people were allowed to meet in groups to walk.

Presently in the UK, groups of 15 people are allowed to meet outside.

He said: “The Ramblers saved me during the last year of lockdowns. I don’t know where I would be without them with my nerves. Within two miles of walking I’m a different person. Dr Jack is an amazing man as he has saved me from my nerves in the lockdowns with this idea of his.”

Jim has walked 6.4 to 8 kilometres a day in the last year.

He said: “I even went out when the roads were icy and always stayed within a five mile radius of South Queensferry during the lockdowns. I hope my story helps someone else who is feeling bad so they know to join their local Ramblers group too.”

Dr Jack, of South Queensferry Medical Practice, told BBC Scotland his own experience with stress was used to inform Jim’s treatment.

“When Jim told me he liked walking but that he had been walking on his own I was aware that he was actually quite socially isolated as his wife had died,” Dr Jack explained. “He was benefitting from the physical part of walking but not the social side. A few years ago I joined a running club and found it very helpful for stress. This has made me recognise that any sports club has a benefit particularly through the social connection it provides.”

Dr Jack said he had seen numerous patients experiencing mental health issues during the lockdown, especially in those working from home.

Brendan Paddy, director of Ramblers Scotland, said: “Jim is truly an inspiration to us all. It’s amazing to see how he’s improved his health and happiness by getting active with his local South Queensferry Ramblers group.

“Clearly lockdown has been a hugely challenging time, yet we know that many more people like Jim are discovering the revitalising power of walking – with booming numbers enjoying Scotland’s outdoors. I’d urge anyone who’d like a bit more adventure, friendship and fresh air in their lives, to give the Ramblers a go.”

Source: BBC News

Categories : ExerciseTags :

With Advanced ‘Vaporfly’ Shoes, Female Runners Close Gap with Males

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Female and male runners in starting positions. Photo by Andrea Piacquadio from Pexels

A new paper found that Nike’s advanced ‘Vaporfly’ footwear reduced running times for both elite male and female competitors.

The introduction of the controversial Nike ‘Vaporfly’ shoes saw world records being broken and a marathon run in under two hours, prompting a review and subsequent ban on the high-tech shoes.

The study compared seasonal best times for elite male and female runners in three race categories—10 kilometres, half marathon and marathon races—from 2012 to 2019. Analysis showed a statistically significant decrease in race times after 2017, which coincided with the premiere of the Nike ‘Vaporfly’.

Female elite athletes appeared to gain the most benefit from the design improvement, which features a thicker, lighter foam and rigid plate along the midsole. Their seasonal best times between 2016 and 2019 fell anywhere from 1.7 to 2.3%, versus 0.6 to 1.5% for the men. In marathons, the new shoe technology improved times for females by about 2 minutes and 10 seconds, a 1.7% percent boost in performance.

“As far as chronometric performance is concerned, it is in our opinion a major advancement,” said lead author Dr Stéphane Bermon, director of the World Athletics Health and Science Department.

How the performance has been achieved is still mostly a mystery. The new shoe technology uses the latest generation of lightweight foam in the midsole, which provides the runner with a higher energy return. The embedded stiff plate in the midsole also contributes to maximising energy return in each step. The net effect is to propel the runner forward with greater ease.

The statistical gap between genders was unexpected, said Dr Bermon. One advantage could come down to weight between the sexes.

“Women are lighter and could possibly benefit more from the enhanced rebound effect achieved by the foam/stiff plate combination,” he said. “Their slightly different running pattern, compared to men, could represent a more favorable condition for this footwear technology to play its ergogenic role.”

A previous 2018 statistical analysis had already suggested a 3 to 4% decrease in half marathon and marathon race times based on hundreds of thousands of self-reported results. However, the present study was the first to compare the top seasonal best times for elite athletes.

While East African runners, like Ethiopian and Kenyan, make up the majority of the results as they have come to dominate the sport, the paper noted that non-East-African elite runners showed similar improvements in performance.

“These results confirm that advanced footwear technology has benefits to the elite male and female distance runners,” Dr Bermon said. “Whether this technology will be banned or simply controlled, as it is currently, is still to be decided by World Athletics.”

No immediate follow-up studies are planned, though Dr Bermon said additional research is needed into injury rates with the new footwear with mass adoption.

Source: Medical Xpress

Journal information: Stéphane Bermon et al, Effect of Advanced Shoe Technology on the Evolution of Road Race Times in Male and Female Elite Runners, Frontiers in Sports and Active Living (2021). DOI: 10.3389/fspor.2021.653173

Categories : Exercise Mental HealthTags :

Mental Health and Physical Activity Impacted by Pandemic

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A study from McMaster University suggests that mental health has become both a barrier to and a motivator for physical activity.

Surveying over 1600 subjects, the researchers sought to understand the ways mental health, physical activity and sedentary behaviour have changed throughout the course of the pandemic and why. Their findings show that people want to be active to improve their mental health but find exercise difficult because of stress and anxiety. Previous research indicates that physical activity can contribute to the treatment of depression, while sedentary behaviour has a strong negative impact.
“Maintaining a regular exercise program is difficult at the best of times and the conditions surrounding the COVID-19 pandemic may be making it even more difficult,” said lead author Jennifer Heisz, associate professor at the Department of Kinesiology, McMaster University.

“Even though exercise comes with the promise of reducing anxiety, many respondents felt too anxious to exercise. Likewise, although exercise reduces depression, respondents who were more depressed were less motivated to get active, and lack of motivation is a symptom of depression,” she said.

The survey respondents reported higher psychological stress and moderate levels of anxiety and depression due to the pandemic. Their weekly aerobic activity reduced about 20 minutes, strength training down roughly 30 minutes, and sedentary time per day was up about 30 minutes per day compared to six months prior to the pandemic. Physical activity may have exerted a protective effect, as those with the greatest drops in physical activity had the worst mental health outcomes, while those who kept their physical activity levels the same level fared better in terms of mental health. 
Notably, economic disparities played a role, the researchers found, especially among younger adults.

“Just like other aspects of the pandemic, some demographics are hit harder than others and here it is people with lower income who are struggling to meet their physical activity goals,” said co-lead author Maryam Marashi, a graduate student in the Department of Kinesiology. “It is plausible that younger adults who typically work longer hours and earn less are lacking both time and space which is taking a toll.”

After the researchers analysed the data, the researchers produced a guideline to help people become more physically active:

  • Adopt a mindset: Some exercise is better than none.
  • Lower exercise intensity if feeling anxious.
  • Move a little every day.
  • Break up sedentary time with standing or movement breaks.
  • Plan your workouts like appointments by blocking off the time in your calendar.

“Our results point to the need for additional psychological supports to help people maintain their physical activity levels during stressful times in order to minimize the burden of the pandemic and prevent the development of a mental health crisis,” concluded Heisz.

Source: News-Medical.Net

Journal information: Marashi, M. Y., et al. (2021) A mental health paradox: Mental health was both a motivator and barrier to physical activity during the COVID-19 pandemic. PLOS ONE. doi.org/10.1371/journal.pone.0239244.

Categories : ExerciseTags :

Intense Exercise Needed to Prevent Heart Changes in Space

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A study of an astronaut and an extreme long distance swimmer has shown that intense exercise is needed to prevent heart changes in space or situations of reduced weight, such as water immersion.

By comparing data from astronaut Scott Kelly’s year in space aboard the International Space Station and comparing it to information from Benoît Lecomte’s  extreme long distance swimming, which simulates weightlessness, researchers found that low-intensity exercise was not enough to counteract the effects of prolonged weightlessness on the heart.

In a sitting or standing position, gravity draws blood into the lower extremities, and removing this effect through water immersion, prolonged bed rest or zero gravity conditions causes the heart to shrink as it no longer has to pump against this effect. Researchers have used the lack of gravity in space to investigate the physiology of ageing and muscle and bone loss, and vice versa.

Researchers examined data from retired astronaut Scott Kelly’s year-long mission aboard the ISS from 2015 to 2016 and elite endurance swimmer Benoît Lecomte’s swim across the Pacific Ocean in 2018.

In this new study, researchers evaluated the effects of long-term weightlessness on the structure of the heart and to help understand whether extensive periods of low-intensity exercise can prevent the effects of weightlessness.

“The heart is remarkably plastic and especially responsive to gravity or its absence. Both the impact of gravity as well as the adaptive response to exercise play a role, and we were surprised that even extremely long periods of low-intensity exercise did not keep the heart muscle from shrinking,” said senior author Benjamin D Levine, MD, and a professor of internal medicine at UT Southwestern Medical Center and director of Texas Health Presbyterian’s Institute for Exercise and Environmental Medicine.

The research team examined medical data from Kelly’s year aboard the ISS and Lecomte’s swim across the Pacific Ocean to investigate the impact of long-term weightlessness on the heart. Water immersion is an excellent model for weightlessness since water offsets gravity’s effects, especially in the prone swimming technique used by long-distance endurance swimmers.

As part of the routine countermeasures to maintain physical fitness in space, Kelly exercised six days a week, one to two hours per day using a stationary bike, a treadmill and resistance activities. Researchers hoped Lecomte’s 159-day 2700km swim from Choshi, Japan, with almost six hours a day of swimming, would keep his heart from shrinking and weakening. Doctors performed various tests to measure the health and effectiveness of both Kelly’s and Lecomte’s hearts before, during and after each man embarked on his respective expeditions.

Both men and Lecomte lost mass from their left ventricles (Kelly 0.74 grams/week; Lecomte 0.72 grams/week). They also suffered an initial shrinkage in the diastolic diameter of their heart’s left ventricle (Kelly’s dropped from 5.3 to 4.6cm; 5 to 4.7cm for Lecomte).

Even the most sustained periods of low-intensity exercise were not enough to counteract the effects of prolonged weightlessness. Left ventricle ejection fraction (LVEF) and markers of diastolic function did not consistently change in either individual throughout their campaign.

Due to its exceptional nature, more study is required to understand how these results can be applied to the general population. 

Lecomte had cardiac MRIs from before and after his swim and analysis of these is forthcoming. These will be helpful for the researchers to further understand whether long-term effects of weightlessness are reversible. Kelly did not receive cardiac MRIs, and currently, there are no further follow up plans for him.

Source: Medical Xpress

Journal information: Circulation (2021). DOI: 10.1161/CIRCULATIONAHA.120.050418