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Category: Exercise

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Moderate levels of exercise seems to have tremendous benefits for everyone, but there are downsides to being an extreme exerciser.  From Science Daily:

Elderly men with high blood pressure lower death risk with moderate fitness

Elderly men with high blood pressure can lower their risk of death with even moderate levels of fitness. "This level of fitness is achievable by most elderly individuals engaging in a brisk walk of 20 to 40 minutes, most days of the week," said Charles Faselis, M.D., lead author of the study.

For the study, researchers assessed the fitness status of 2,153 men, aged 70 years and older with high blood pressure by a standard treadmill exercise test. Researchers applied the international units used to measure fitness, called metabolic equivalents (METs), to determine the men's peak fitness levels. After an average follow-up of nine years, researchers found that the risk of death was 11 percent lower for every one-MET increase in exercise capacity.

"For every 100 people who died in the least-fit category, 82 died in the low-fit, 64 in the moderate-fit and 52 in the high-fit categories," Kokkinos said. "The death rate is cut in half for those in the highest fitness category."

Too much exercise also has negatives for men. From Medical Xpress:

Too much prolonged high-intensity exercise risks heart health

Overdosing on high intensity exercise may actually increase the risk of death from a heart attack or stroke in those with existing heart disease, suggests German research published online in the journal Heart.

Similarly, a second Swedish study in the journal suggests that young men undertaking endurance exercise for more than five hours a week may increase their risk of developing an irregular heart rhythm in later life.

Both sets of findings indicate a J-shaped curve for the health benefits of exercise... And they describe "a similar U-shaped or reverse J-shaped pattern for the dose-response effect of exercise: maximum cardiovascular benefits are obtained if performed at moderate doses, while these benefits are lost with (very high) intensity and prolonged efforts."

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It seems that research showing benefits of exercise is multiplying. This study only looked at men, and if you look at the "after age 40 group", their average age of starting endurance training was 48. From Science Daily:

Forty not too old or too late to start endurance training

A study of healthy senior men has found that "relatively intensive" endurance exercise confers benefits on the heart irrespective of the age at which they began training. The benefits were evident and comparable in those who had started training before the age of 30 or after the age of 40. As a result, said the investigators, 40 is not too old to start endurance training.

The study was performed in 40 healthy men (without cardiovascular risk factors) aged between 55 and 70 years who were divided for assessment according to the level of exercise they took and the ages at which they began. Thus, 10 of the men had never exercised for more than 2 hours a week throughout their lives, and 30 had exercised for at least 7 hours a week for over five years.

The regular exercise they took was either running or cycling. Those beginning before the age of 30 had been training for an average of 39 years (since the age of 22) and those starting at 40 for 18 years (since the age of 48).

First, resting heart rate was found to be similar between the two exercise groups (T30 56.8 bpm, T40 58.1 bpm), but significantly faster in the non-exercising men (69.7 bpm). Maximal oxygen uptake was also similar between the T30 (47.3 ml/min/kg) and T40 groups (44.6 ml/min/kg), but significantly lower in the non-exercising men (33.0 ml/min/kg).

The study also found no difference between T30 and T40 in cardiac echocardiography tests. "Thus," said Matelot, "despite biological changes with age, the heart still seems -- even at the age of 40 -- amenable to modification by endurance training. Starting at the age of 40 does not seem to impair the cardiac benefits.

Matelot pointed out that aging is associated with adverse structural and functional changes to the cardiovascular system. And, while physical activity is unable to prevent these changes, it is able to slow them down.

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Once again research shows problems with physical inactivity: this time heart disease risk in women. From Science Daily:

From age 30 onwards, inactivity has greatest impact on women's lifetime heart disease risk

From the age of 30 onwards, physical inactivity exerts a greater impact on a woman's lifetime risk of developing heart disease than the other well-known risk factors, suggests research published online in the British Journal of Sports Medicine. This includes overweight. the findings show, prompting the researchers to suggest that greater effort needs to be made to promote exercise.

The researchers wanted to quantify the changing contribution made to a woman's likelihood of developing heart disease across her lifetime for each of the known top four risk factors in Australia: excess weight (high BMI); smoking; high blood pressure; and physical inactivity. Together, these four risk factors account for over half the global prevalence of heart disease, which remains the leading cause of death in high income countries.

They based their calculations on estimates of the prevalence of the four risk factors among 32,154 participants in the Australian Longitudinal Study on Women's Health, which has been tracking the long term health of women born in 1921-6, 1946-51, and 1973-8, since 1996.

Combining the prevalence and relative risk data, the researchers found that up to the age of 30, smoking was the most important contributor to heart disease, with a PAR of 59%. But from age 30 until the late 80s, low physical activity levels were responsible for higher levels of population risk than any of the other risk factors.

The researchers estimate that if every woman between the ages of 30 and 90 were able to reach the recommended weekly exercise quota -- 150 minutes of at least moderate intensity physical activity -- then the lives of more than 2000 middle aged and older women could be saved each year in Australia alone.

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Years ago the advice was to really limit exercise during pregnancy, but times have changed. Now studies find exercise during pregnancy beneficial for both the mother and baby. From Discover:

Exercise During Pregnancy Benefits Mom—And Baby, Too

Women who exercise with baby on board have been known to have, among other things, lower risks of gestational diabetes and pregnancy-induced high blood pressure than those who don’t.

In 1985, the American Congress of Obstetricians and Gynecologists came out with their first set of guidelines for exercise during pregnancy—guidelines, now considered conservative, that included suggestions like keeping strenuous activities to 15 minutes or less. Since then, research has turned that idea on its head. Exercise is now thought to be—for most women with healthy pregnancies—a boon for the mother's health, and for the baby she carries as well.

It’s been known that those who exercise—including pregnant women—tend to have lower resting heart rates than those who don’t. Lower heart rates can be a sign of an efficient heart; high heart rates have been linked to greater risk of cardiovascular disease. May, now at East Carolina University in North Carolina, has long been interested whether benefits like this extended to baby.  In a 2010 study, she and her colleagues collected a group of 26 pregnant women who reported that they’d been exercising three times a week for more than 30 minutes per session.  When researchers brought the moms into the lab at 36 weeks, they found that the babies in their bellies, too, had lower heart rates than those carried by the moms they studied who weren’t regular exercisers.

The results indicate that exercise during pregnancy, far from harming the fetus, can be incredibly beneficial for both mom and baby. And timing matters: exercise during pregnancy, as opposed to pre-pregnancy fitness, seems to be doing something extra-special, May says. In this most recent study, about half of the group hadn’t exercised previously, and still saw similar effects on their babies’ hearts. 

Such benefits to the heart may last into a child’s early life. Earlier this year, May and colleagues found that month-old infants still had higher heart rate variability if they had exercised along with their moms in utero. Another set of results from May’s group, not yet published, suggests that kids up to six years old still carry some of these early workouts with them: youngsters whose moms exercised while pregnant have higher “ejection fractions,” which indicates their hearts are pumping blood more efficiently.

Studies report that only about 10 to 30 percent of pregnant women are following recommended exercise guidelines—for healthy women, at least 30 minutes of moderate exercise most, if not all, days, according to the American Congress of Obstetricians and Gynecologists.. (Of course, some women can’t safely exercise during part or all of their pregnancy, and active women should watch out for warning signs while exercising, such as bleeding or contractions.)

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More studies on the amazing benefits of exercise, or activity, even light activity.  From Science Daily:

Simple tests of physical capability in midlife linked with survival

Low levels of physical capability (in particular weak grip strength, slow chair rise speed and poor standing balance performance) in midlife can indicate poorer chances of survival over the next 13 years, while greater time spent in light intensity physical activity each day is linked to a reduced risk of developing disability in adults with or at risk of developing knee osteoarthritis, suggest two papers published on bmj.com today.

The researchers conclude that there are "robust associations of standing balance time, chair rise speed and grip strength at age 53 with all-cause mortality rates over 13 years of follow-up." They suggest there is value in using these simple tests to assess physical capability in midlife to identify those people who are less likely to achieve a "long and healthy life."

In a linked paper, a team of US researchers set out to investigate whether time spent in light intensity physical activity is related to a reduced risk of developing disability and disability progression.

Their study involved 1,680 men and women aged 49-83 years free of disability, but with or at high risk for developing knee osteoarthritis, a major disability risk factor. The primary outcome was the development of disability at a two-year follow up visit. In total, participants averaged 245 minutes/day of non-sedentary activity, of which the vast majority was light intensity activities (229 minutes/day).

The results show a "significant and consistent relationship between greater time spent in light intensity activity and a reduced risk of developing disability or progression in disability," say the authors.

More details on the second study. From Science Daily:

Light activity every day keeps disability at bay

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More research on the benefits of exercise. From Science Daily:

Road to fountain of youth paved with fast food ... and sneakers? Exercise may prevent or delay fundamental process of aging

We all know that too much food combined with too little exercise can add up to poor health and disease. But overeating and inactivity also speed up the aging process, right down to our cells. At the end of a cell's lifespan, a process called senescence kicks in -- cells lose the ability to divide and begin to secrete substances that damage the surrounding cells. While unhealthy lifestyle habits can accelerate this process, researchers at the Mayo Clinic wanted to know if increased exercise could counteract it. 

The research team compared mice fed a fast food diet (FFD) for 5 months with those fed a standard chow diet (control). Unlike the controls, the FFD mice developed insulin sensitivity, impaired glucose tolerance, impaired exercise ability, and heart dysfunction. But when the FFD mice were given a running wheel, the exercise began to counteract the effects of a poor diet. White et al. observed a number of improvements including body weight, metabolism, and cardiac function. They also saw a significant decrease in signs of cell senescence and associated inflammation.

"Our data clearly show that poor nutritional choices dramatically accelerate the accumulation of senescent cells, and for the first time, that exercise can prevent or delay this fundamental process of aging. 

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Based on this research, the message stays the same: get out there and exercise for healthy aging. From Medical Xpress:

Midlife occupational and leisure-time physical activity limits mobility in old age

Strenuous occupational physical activity in midlife increases the risk of mobility limitation in old age, whereas leisure-time physical activity decreases the risk. This is found in a study which followed up 5,200 public sector employees for 28 years. The study was conducted at the Gerontology Research Center in Finland and the Finnish Institute of Occupational Health.

Heavy physical labor is often repetitive, wears the body and lasts for several hours a day. On the contrast, leisure-time physical activity is designed to improve fitness and provide recreation and a typical exercise session lasts for one or two hours. Even though both are based on muscle activity and result in energy expenditure, their long-term consequences are different.

"A person doing heavy manual work may compensate for its detrimental effects by participating in brisk leisure-time physical activity," says professor Taina Rantanen, the leader of the research group.

Mobility limitation was assessed five times and was based on a person's ability to maintain and change body positions, carry and handle objects and walk and move. The baseline assessment took place in 1981 and the last assessment in 2009. 

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Youthful skin (even reversing the effects of aging!) is an excellent reason to exercise. And apparently it's never too late to start. From NY Times:

Younger Skin Through Exercise

Exercise not only appears to keep skin younger, it may also even reverse skin aging in people who start exercising late in life, according to surprising new research.

As many of us know from woeful experience, our skin changes as the years advance, resulting in wrinkles, crow’s feet and sagging skin. This occurs because of changes within our layers of skin. After about age 40, most of us begin to experience a thickening of our stratum corneum, the final, protective, outer layer of the epidermis, itself the top layer of your skin. The stratum corneum is the portion of the skin that you see and feel. Composed mostly of dead skin cells and some collagen, it gets drier, flakier and denser with age.

At the same time, the layer of skin beneath the epidermis, the dermis, begins to thin. It loses cells and elasticity, giving the skin a more translucent and often saggier appearance. These changes are independent of any skin damage from the sun. They are solely the result of the passage of time.

But recently, researchers at McMaster University in Ontario began to wonder if such alterations were inevitable. Earlier studies at McMaster involving mice that were bred to age prematurely had shown that a steady regimen of exercise could stave off or even undo the signs of early aging in these animals. 

Of course, we humans long ago swapped our fur for naked skin. But if exercise could keep animals’ outer layer from changing with age, it might, the researchers speculated, do the same for our skin.

To test that possibility, the scientists first gathered 29 local male and female volunteers ages 20 to 84. About half of the participants were active, performing at least three hours of moderate or vigorous physical activity every week, while the others were resolutely sedentary, exercising for less than an hour per week. Then the researchers asked each volunteer to uncover a buttock. “We wanted to examine skin that had not been frequently exposed to the sun,” said Dr. Mark Tarnopolsky.

The scientists biopsied skin samples from each volunteer and examined them microscopically. When compared strictly by age, the skin samples overall aligned with what would be expected. Older volunteers generally had thicker outer layers of skin and significantly thinner inner layers. But those results shifted noticeably when the researchers further subdivided their samples by exercise habits. They found that after age 40, the men and women who exercised frequently had markedly thinner, healthier stratum corneums and thicker dermis layers in their skin. Their skin was much closer in composition to that of the 20- and 30-year-olds than to that of others of their age, even if they were past age 65.

So the researchers next got skin samples from their buttocks. The volunteers were aged at 65 or older and, at the study’s start, had normal skin for their age. They began a fairly straightforward endurance training program, working out twice a week by jogging or cycling at a moderately strenuous pace, equivalent to at least 65 percent of their maximum aerobic capacity for 30 minutes. This continued for three months. At the end of that time, the researchers again biopsied the volunteers’ skin.

But now the samples looked quite different, with outer and inner layers that looked very similar to those of 20- to 40-year-olds. “I don’t want to over-hype the results, but, really, it was pretty remarkable to see,” said Dr. Tarnopolsky, himself a middle-aged exerciser. Under a microscope, the volunteers’ skin “looked like that of a much younger person, and all that they had done differently was exercise.”

How exercise changes skin composition is not completely clear, but in a separate portion of the study, the researchers checked for alterations in the levels of certain substances created by working muscles. Called myokines, these substances are known to enter the bloodstream and jump-start changes in cells far from the muscles themselves. In this case, the scientists found greatly augmented levels of a myokine called IL-15 in the skin samples of volunteers after exercise. Their skin samples contained almost 50 percent more IL-15 after they had been exercising than at the start of the study.

The researchers suspect that additional myokines and substances are also involved in the skin changes related to exercise, Dr. Tarnopolsky said, making it unlikely that any IL-15 pill, salve or injection will ever replicate the skin benefits of a workout. Nor is there evidence that exercise reverses wrinkling and other damage from the sun, some of which many of us accumulate during outdoor exercise. 

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The benefits of exercise and being fit keeps growing. From Medical Daily:

Physical Fitness In Your 20s Can Help Preserve Your Thinking Skills Later On In Life

If you need some motivation to get up off the couch and in your running shoes than how about this; a new study has proved that those who are fitter in their 20s are sharper thinkers in their middle age. So not only does exercise improve your health, slim your waistline, and lift your mood, but apparently it can also make you smarter. 

The study was carried out by researchers at the University of California, San Francisco. It started in 1985 and was conducted on nearly 3,000 19- to 30-year-olds in the U.S. The participants were asked to do a treadmill test and undergo physical examinations. They were asked to run for as long as they could without becoming exhausted or short of breath, according to the BBC. Then, 20 years later, the participants agreed to repeat the physical test. Five years after the second physical exam the participants underwent brain testing. These included a word recall test, a number-based test of attention, thinking speed and memory, and a test of how well people can focus while tuning out distractions. Results showed that the better people did on the treadmill test 20 years earlier, the better they did on the memory test. Also, those who had kept up their fitness later on in life scored the best overall in the memory tests. The researchers took into account factors such as weight, sex, drinking, smoking, and education. Still, those who did better on the treadmill test seemed to do better on the memory tests years later. 

The reasoning for this is that the brain uses a lot of oxygen and people who are fitter make more efficient use of oxygen. Also, exercise improves mitochondrial function, which is necessary in making use of energy. It is emphasized that this increase in brain function cannot be attributed to exercise alone. People who are physically fit are less likely to be sat in front of a television and more likely to interact with people and be engaged in life. “Just moving around — being engaged in family and life as opposed to sitting down and watching TV and pretty much not doing anything, they are going to preserve brain function. This is really about engagement in life,” lead researcher David Jacobs told NBC News. The study will continue by observing whether physical fitness in youth makes individuals less likely to develop Alzheimer’s disease later on in life. “Investment in research is vital to better understand how we can protect our brains as we age,” Jacobs concluded.

This research also ties in with another study released this week that showed young adults who had better heart health, as measured by blood pressure, have better thinking skills in middle age than those with high blood pressure.

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Last month (Feb. 12, 2014) I posted two studies that discussed the link between exercise and health, including eye health and macular degeneration. This following article builds on those studies to discuss the link between eye health and exercise, how exercise could protect our eyes from age-related vision loss, and even repair eye damage.

From the NY Times: Exercising for Healthier Eyes

There have been suggestions that exercise might reduce the risk of macular degeneration, which occurs when neurons in the central part of the retina deteriorate. The disease robs millions of older Americans of clear vision. A 2009 study of more than 40,000 middle-aged distance runners, for instance, found that th0se covering the most miles had the least likelihood of developing the disease. But the study did not compare runners to non-runners, limiting its usefulness. It also did not try to explain how exercise might affect the incidence of an eye disease. 

So, more recently, researchers at Emory University in Atlanta and the Atlanta Veterans Administration Medical Center in Decatur, Ga., took up that question for a study published last month in the Journal of Neuroscience. Their interest was motivated in part by animal research at the V.A. medical center. That work had determined that exercise increases the levels of substances known as growth factors in the animals’ bloodstream and brains. These growth factors, especially one called brain-derived neurotrophic factor, or B.D.N.F., are known to contribute to the health and well-being of neurons and consequently, it is thought, to improvements in brain health and cognition after regular exercise.

But the brain is not the only body part to contain neurons, as the researchers behind the new study knew. The retina does as well, and the researchers wondered whether exercise might raise levels of B.D.N.F. there, too, potentially affecting retinal health and vision.

To test that possibility, the researchers gathered adult, healthy lab mice. Half of these were allowed to remain sedentary throughout the day, while the other animals began running on little treadmills at a gentle rodent pace for about an hour a day. After two weeks, half of the mice in each group were exposed to a searingly bright light for four hours. The other animals stayed in dimly lit cages. This light exposure is a widely used and accepted means of inducing retinal degeneration in animals. It doesn’t precisely mimic the slowly progressing disease in humans, obviously. But it causes a comparable if time-compressed loss of retinal neurons.

The mice then returned to their former routine — running or not exercising — for another two weeks, after which the scientists measured the number of neurons in each animal’s eyes. The unexercised mice exposed to the bright light were experiencing, by then, severe retinal degeneration. Almost 75 percent of the neurons in their retinas that detect light had died. The animals’ vision was failing.

But the mice that had exercised before being exposed to the light retained about twice as many functioning retinal neurons as the sedentary animals; in addition, those cells were more responsive to normal light than the surviving retinal neurons in the unexercised mice. Exercise, it seems, had armored the runners’ retinas.

Separately, the researchers had other mice run or sit around for two weeks, and then measured levels of B.D.N.F. in their eyes and bloodstreams. The runners had far more. Tellingly, when the scientists injected still other mice with a chemical that blocks the uptake of the growth factor before allowing them to run and exposing them to the bright light, their eyes deteriorated as badly as among sedentary rodents. When the mice could not process B.D.N.F., exercise did not safeguard their eyes.

Taken together, these experiments strongly suggest that “exercise protects vision, at least in mice, by increasing B.D.N.F. in the retina,” said Jeffrey Boatright, an associate professor of ophthalmology at Emory University School of Medicine and a co-author of the study.

For now, she and Dr. Boatright said, people who are concerned about their vision, and especially those with a family history of retinal degeneration, might want to discuss an exercise program with their doctor. “As potential treatments go,” she said, “it’s cheap, easy and safe.”