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Category: 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.”

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Article about the growing body of research supporting exercise in the treatment of depression. From The Atlantic:

For Depression, Prescribing Exercise Before Medication

Depression is the most common mental illness—affecting a staggering 25 percent of Americans—but a growing body of research suggests that one of its best cures is cheap and ubiquitous. In 1999, a randomized controlled trial showed that depressed adults who took part in aerobic exercise improved as much as those treated with Zoloft. A 2006 meta-analysis of 11 studies bolstered those findings and recommended that physicians counsel their depressed patients to try it. A 2011 study took this conclusion even further: It looked at 127 depressed people who hadn’t experienced relief from SSRIs, a common type of antidepressant, and found that exercise led 30 percent of them into remission—a result that was as good as, or better than, drugs alone.

Though we don’t know exactly how any antidepressant works, we think exercise combats depression by enhancing endorphins: natural chemicals that act like morphine and other painkillers. There’s also a theory that aerobic activity boosts norepinephrine, a neurotransmitter that plays a role in mood. And like antidepressants, exercise helps the brain grow new neurons.

But this powerful, non-drug treatment hasn’t yet become a mainstream remedy. In a 2009 study, only 40 percent of patients reported being counseled to try exercise at their last physician visit.

Instead, Americans are awash in pills. The use of antidepressants has increased 400 percent between 1988 and 2008. They’re now one of the three most-prescribed categories of drugs, coming in right after painkillers and cholesterol medications.

After 15 years of research on the depression-relieving effects of exercise, why are there still so many people on pills? The answer speaks volumes about our mental-health infrastructure and physician reimbursement system, as well as about how difficult it remains to decipher the nature of depression and what patients want from their doctors.

When it comes to non-drug remedies for depression, exercise is actually just one of several promising options. Over the past few months, research has shown that other common lifestyle adjustments, like meditating or getting more sleep, might also relieve symptoms. Therapy has been shown to work just as well as SSRIs and other medications. In fact, a major JAMA study a few years ago cast doubt on the effectiveness of antidepressants in general, finding that the drugs don't function any better than placebo pills for people with mild or moderate depression.

The half-dozen psychiatrists I interviewed said they’ve started to incorporate non-drug treatments into their plans for depressed patients. But they said they’re only able to do that because they don’t accept insurance. (One of the doctors works for a college system and only sees students.)

That’s because insurers still largely reimburse psychiatrists, like all other doctors, for each appointment—whatever that appointment may entail—rather than for curing a given patient. It takes less time to write a prescription for Zoloft than it does to tease out a patient’s options for sleeping better and breaking a sweat. Fewer moments spent mapping out jogging routes or sleep schedules means being able to squeeze in more patients for medications each day.

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Another study discussing how physical activity reduces the risk of breast cancer for women of all ages and sizes. From Science Daily:

Regular physical activity reduces breast cancer risk irrespective of age

Practicing sport for more than an hour day reduces the risk of contracting breast cancer, and this applies to women of any age and any weight, and also unaffected by geographical location, according to research presented to the 9th European Breast Cancer Conference (EBCC-9). Compared with the least active women, those with the highest level of physical activity reduced their risk of breast cancer by 12%, researchers say.

Professor Mathieu Boniol, Research Director at the International Prevention Research Institute, Lyon, France, recently reported the results of a meta-analysis of 37 studies published between 1987 and 2013, representing over four million women. "These are all the studies looking at the relationship between physical exercise and breast cancer risk that have been published to date, so we are confident that the results of our analysis are robust," he said.

Although the results varied according to tumour type, the overall message was encouraging, the researchers say. However, in women taking hormone replacement therapy (HRT), the protective effect of exercise seemed to be cancelled out. But increased awareness of the side effects of HRT means that its use is decreasing in a number of countries, and this means that the beneficial effects of activity will most likely grow in the years to come. 

Physical activity is known to have a protective role in other cancers, as well as in disorders such as cardiovascular disease. Although the mechanisms for its effect are unclear, the results are largely independent of body mass index (BMI), so the effect must be due to more than weight control. And the age at which sporting activity starts also appears to be immaterial; the researchers found no indication that breast cancer risk would decrease only when physical activity started at a young age.

"Adding breast cancer, including its aggressive types, to the list of diseases that can be prevented by physical activity should encourage the development of cities that foster sport by becoming bike and walk-friendly, the creation of new sports facilities, and the promotion of exercise through education campaigns," said Prof Boniol. 

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Over and over research shows that moving your body is a key to good health. And to build muscles one has to move a lot. From Science Daily:

Older adults: Build muscle and you'll live longer

New UCLA research suggests that the more muscle mass older Americans have, the less likely they are to die prematurely. The findings add to the growing evidence that overall body composition - and not the widely used body mass index, or BMI -- is a better predictor of all-cause mortality.

The researchers analyzed data collected by the National Health and Nutrition Examination Survey (NHANES) III, conducted between 1988 and 1994. They focused on a group of 3,659 individuals that included men who were 55 or older and women who were 65 or older at the time of the survey. The authors then determined how many of those individuals had died from natural causes based on a follow-up survey done in 2004.

The body composition of the study subjects was measured using bioelectrical impedance, which involves running an electrical current through the body. Muscle allows the current to pass more easily than fat does, due to muscle's water content. In this way, the researchers could determine a muscle mass index -- the amount of muscle relative to height -- similar to a body mass index. They looked at how this muscle mass index was related to the risk of death. They found that all-cause mortality was significantly lower in the fourth quartile of muscle mass index compared with the first quartile.

"In other words, the greater your muscle mass, the lower your risk of death," said Dr. Arun Karlamangla, an associate professor in the geriatrics division at the Geffen School and the study's co-author. "Thus, rather than worrying about weight or body mass index, we should be trying to maximize and maintain muscle mass."

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More studies showing health benefits of moving and exercise. From Science Daily:

Dangers of ... sitting? Regardless of exercise, too much sedentary time is linked to major disability after 60

If you're 60 and older, every additional hour a day you spend sitting is linked to doubling the risk of being disabled -- regardless of how much moderate exercise you get, reports a new Northwestern Medicine study.

The study is the first to show sedentary behavior is its own risk factor for disability, separate from lack of moderate vigorous physical activity. In fact, sedentary behavior is almost as strong a risk factor for disability as lack of moderate exercise.

If there are two 65-year-old women, one sedentary for 12 hours a day and another sedentary for 13 hours a day, the second one is 50 percent more likely to be disabled, the study found.

"This is the first time we've shown sedentary behavior was related to increased disability regardless of the amount of moderate exercise," said Dorothy Dunlop, professor of medicine at Northwestern University Feinberg School of Medicine and lead author of the study. "Being sedentary is not just a synonym for inadequate physical activity."

Disability affects more than 56 million Americans. It's defined by limitations in being able to do basic activities such as eating, dressing or bathing oneself, getting in and out of bed and walking across a room. Disability increases the risk of hospitalization and institutionalization and is a leading source of health care costs, accounting for $1 in $4 spent.

The study focused on a sample of 2,286 adults aged 60 and older from the National Health and Nutrition Examination Survey. It compared people in similar health with the same amount of moderate vigorous activity. Moderate activity is walking briskly, as if you are late to an appointment.

The participants wore accelerometers from 2002 to 2005 to measure their sedentary time and moderate vigorous physical activity. The accelerometer monitoring is significant because it is objective.

From Science Daily:

Exercise may slow progression of retinal degeneration

Moderate aerobic exercise helps to preserve the structure and function of nerve cells in the retina after damage, according to an animal study appearing February 12 in The Journal of Neuroscience. The findings suggest exercise may be able to slow the progression of retinal degenerative diseases.

Age-related macular degeneration, one of the leading causes of blindness in the elderly, is caused by the death of light-sensing nerve cells in the retina called photoreceptors. Although several studies in animals and humans point to the protective effects of exercise in neurodegenerative diseases or injury, less is known about how exercise affects vision.

This is the first report of simple exercise having a direct effect on retinal health and vision," Pardue said. "This research may one day lead to tailored exercise regimens or combination therapies in treatments of blinding diseases."

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It appears most of us sit too much. From Science Daily:

Obese Americans get less than one minute of vigorous activity per day, research shows

Researchers at the University of South Carolina’s Arnold School of Public Health have validated a new method for calculating physical activity, sedentary behavior, and the food energy requirements of Americans. The results suggest that as a nation, we spend more than 15 hours per day sleeping and sitting, and that obese men and women spend less than one minute per day in vigorous activity.

The study of the Physical Activity Ratio (PAR) protocol is significant because it provides the first nationally representative estimates of total daily energy expenditure, physical activity and sedentary behavior for the U.S. population.

Data sets for the study were obtained from the National Health and Nutrition Examination Survey 2005-2006, a complex sample of the U.S. population conducted by the Centers for Disease Control and Prevention, and included adults age 20 to 74. The sample population was then divided into three Body Mass Index (BMI) categories: normal weight (18-25 kg/m2), overweight (25-29.9 kg/m2) and obese (30 kg/m2 or more) and took into account all factors contributing to energy expenditure, including sleep, and the digestion and metabolism of food.

The study found that the 1,272 men and 1,325 women that comprised the final sample exhibited key differences based on sex and BMI. Men were taller, heavier, and had greater resting energy expenditure than women. Men also spent more hours per day engaging in moderate and vigorous physical activity, and reported less sleep.

Not surprisingly, obese men and women were significantly less physically active and spent more time in sedentary behaviors than their normal weight counterparts. Obese men and women also reported less sleep and spent almost no time in more intense forms of physical activity. “Given that physical inactivity is now a leading cause of death and disability in the world, these data are essential in advancing the science of obesity and health,” Archer said.

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The following two articles discuss exercise and healthy aging. The first discusses Olga Kotelko and Bruce Grierson (author of the book "What Makes Olga Run").  From the Feb. 10, 2014 New York Times:

Seeking the Keys to Longevity in ‘What Makes Olga Run?’

No one would mistake Olga Kotelko for one of the Olympians competing in Sochi, Russia, but at age 94, she holds more world records than most: 26, to be exact, including age-group bests in the high jump, the hammer throw and the 200-meter run. Not bad for someone who took up track and field at age 77.

The result is this jolly book, which follows the pair as they consult researchers in fields like gerontology, exercise physiology and genetics for insights into Ms. Kotelko’s remarkable youthfulness.

What they find are countless opinions, but little definitive proof. Genes, diet, temperament, the theories abound. (Mr. Grierson rules out performance-enhancing drugs.) Or maybe it’s the exercise itself.

Research on twins suggests that heredity accounts for only about 25 percent to 30 percent of longevity, so it is not enough simply to label Ms. Kotelko a “genetic freak.” Besides, tests show she lacks at least one gene associated with longevity, and it turns out that her telomeres, chromosome caps that shorten with age, are merely average in length.

As for her diet, it is abundant and promiscuous. Her staples include red meat, sauerkraut, cottage cheese and sour milk, and she eats “immoderate amounts” of tapioca pudding. A centenarian friend of hers, the Australian shot-putter Ruth Frith, eschews vegetables altogether.

Among the potential anti-aging elixirs Mr. Grierson explores, exercise appears most potent. This old standby doesn’t just keep hearts pumping and muscles strong; studies suggest it may protect the mind too, by promoting the formation of neurons in the hippocampus — a part of the brain associated with memory.

Since she began her track and field career, Ms. Kotelko has rarely remained still, and that active lifestyle may be more important than her workouts at the track.

From the Feb. 7, 2014 Science Daily:

Exercise may slow progression of retinal degeneration

Moderate aerobic exercise helps to preserve the structure and function of nerve cells in the retina after damage, according to an animal study appearing February 12 in The Journal of Neuroscience. The findings suggest exercise may be able to slow the progression of retinal degenerative diseases.

Age-related macular degeneration, one of the leading causes of blindness in the elderly, is caused by the death of light-sensing nerve cells in the retina called photoreceptors. Although several studies in animals and humans point to the protective effects of exercise in neurodegenerative diseases or injury, less is known about how exercise affects vision.

Machelle Pardue, PhD, together with her colleagues Eric Lawson and Jeffrey H. Boatright, PhD, at the Atlanta VA Center for Visual and Neurocognitive Rehabilitation and Emory University, ran mice on a treadmill for two weeks before and after exposing the animals to bright light that causes retinal degeneration. The researchers found that treadmill training preserved photoreceptors and retinal cell function in the mice.

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From the January 15, 2014 Science Daily:

Don’t Just Sit There! Prolonged Sitting Linked to Early Mortality in Women

Led by Cornell University nutritional scientist Rebecca Seguin, a new study of 93,000 postmenopausal American women found those with the highest amounts of sedentary time -- defined as sitting and resting, excluding sleeping -- died earlier than their most active peers. The association remained even when controlling for physical mobility and function, chronic disease status, demographic factors and overall fitness -- meaning that even habitual exercisers are at risk if they have high amounts of idle time.

Seguin and co-authors found that women with more than 11 hours of daily sedentary time faced a 12 percent increase in all-cause premature mortality compared with the most energetic group -- those with four hours or less of inactivity. The former group also upped their odds for death due to cardiovascular disease, coronary heart disease and cancer by 13, 27 and 21 percent, respectively.

The assumption has been that if you're fit and physically active, that will protect you, even if you spend a huge amount of time sitting each day," said Seguin, assistant professor of nutritional sciences in Cornell's College of Human Ecology. "In fact, in doing so you are far less protected from negative health effects of being sedentary than you realize."

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The importance of 5 healthy behaviors in having the best chance of leading a disease free life. The 5 behaviors are: taking regular exercise, non-smoking, a low body weight, a healthy diet and a low alcohol intake. And as the researchers point out: "healthy behaviors have a far more beneficial effect than any medical treatment or preventative procedure".From Science Daily:

35 Year Study Finds Exercise Reduces Risk of Dementia

The study identifies five healthy behaviors as being integral to having the best chance of leading a disease-free lifestyle: taking regular exercise, non-smoking, a low body weight, a healthy diet and a low alcohol intake.

The people who consistently followed four or five of these behaviors experienced a 60 per cent decline in dementia and cognitive decline -- with exercise being the strongest mitigating factor -- as well as 70 per cent fewer instances of diabetes, heart disease and stroke, compared with people who followed none.

"The size of reduction in the instance of disease owing to these simple healthy steps has really amazed us and is of enormous importance in an aging population," said Principle Investigator Professor Peter Elwood from Cardiff University's School of Medicine. "What the research shows is that following a healthy lifestyle confers surprisingly large benefits to health -- healthy behaviors have a far more beneficial effect than any medical treatment or preventative procedure.

The Caerphilly Cohort Study recorded the healthy behaviors of 2,235 men aged 45-59 in Caerphilly, South Wales.