How Exercise Affects the Brain

Exercise clears the mind. It gets the blood pumping and more oxygen is delivered to the brain. This is familiar territory, but Dartmouth's David Bucci thinks there is much more going on.

Exercise clears the mind. It gets the blood pumping and more oxygen is delivered to the brain. This is familiar territory, but Dartmouth's David Bucci thinks there is much more going on [Credit: Web]

"In the last several years there have been data suggesting that neurobiological changes are happening -- [there are] very brain-specific mechanisms at work here," says Bucci, an associate professor in the Department of Psychological and Brain Sciences.

From his studies, Bucci and his collaborators have revealed important new findings:

• The effects of exercise are different on memory as well as on the brain, depending on whether the exerciser is an adolescent or an adult.

• A gene has been identified which seems to mediate the degree to which exercise has a beneficial effect. This has implications for the potential use of exercise as an intervention for mental illness.

Bucci began his pursuit of the link between exercise and memory with attention deficit hyperactivity disorder (ADHD), one of the most common childhood psychological disorders. Bucci is concerned that the treatment of choice seems to be medication.

"The notion of pumping children full of psycho-stimulants at an early age is troublesome," Bucci cautions. "We frankly don't know the long-term effects of administering drugs at an early age -- drugs that affect the brain -- so looking for alternative therapies is clearly important."

Anecdotal evidence from colleagues at the University of Vermont started Bucci down the track of ADHD. Based on observations of ADHD children in Vermont summer camps, athletes or team sports players were found to respond better to behavioral interventions than more sedentary children. While systematic empirical data is lacking, this association of exercise with a reduction of characteristic ADHD behaviors was persuasive enough for Bucci.

Coupled with his interest in learning and memory and their underlying brain functions, Bucci and teams of graduate and undergraduate students embarked upon a project of scientific inquiry, investigating the potential connection between exercise and brain function. They published papers documenting their results, with the most recent now available in the online version of the journal Neuroscience.

Bucci is quick to point out that "the teams of both graduate and undergraduates are responsible for all this work, certainly not just me." Michael Hopkins, a graduate student at the time, is first author on the papers.

Early on, laboratory rats that exhibit ADHD-like behavior demonstrated that exercise was able to reduce the extent of these behaviors. The researchers also found that exercise was more beneficial for female rats than males, similar to how it differentially affects male and female children with ADHD.

Moving forward, they investigated a mechanism through which exercise seems to improve learning and memory. This is "brain derived neurotrophic factor" (BDNF) and it is involved in growth of the developing brain. The degree of BDNF expression in exercising rats correlated positively with improved memory, and exercising as an adolescent had longer lasting effects compared to the same duration of exercise, but done as an adult.

"The implication is that exercising during development, as your brain is growing, is changing the brain in concert with normal developmental changes, resulting in your having more permanent wiring of the brain in support of things like learning and memory," says Bucci. "It seems important to [exercise] early in life."

Bucci's latest paper was a move to take the studies of exercise and memory in rats and apply them to humans. The subjects in this new study were Dartmouth undergraduates and individuals recruited from the Hanover community.

Bucci says that, "the really interesting finding was that, depending on the person's genotype for that trophic factor [BDNF], they either did or did not reap the benefits of exercise on learning and memory. This could mean that you may be able to predict which ADHD child, if we genotype them and look at their DNA, would respond to exercise as a treatment and which ones wouldn't."

Bucci concludes that the notion that exercise is good for health including mental health is not a huge surprise. "The interesting question in terms of mental health and cognitive function is how exercise affects mental function and the brain." This is the question Bucci, his colleagues, and students continue to pursue.

Author: Joseph Blumberg | Source: Dartmouth College [May 18, 2013]

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Exercise cuts bowel cancer risk

Researchers at the University of Western Australia (UWA) and the Western Australian Institute for Medical Research (WAIMR) have found people who engage in vigorous physical activity may be protected against types of colorectal cancer. 

The study, published in the Cancer Causes Control journal, used a Western Australian cohort.  

Researchers examined 870 participants who had bowel cancer and a control group of 996 who did not have the disease. 

Study participants were asked to answer questions about their recreational physical activity, lifestyle, diet, medication and occupation. 

UWA PhD student Terry Boyle, also supported by the Lions Cancer Institute, says the study confirms previous research that shows the most physically active have a lower risk of bowel cancer than the least active.  

“It also gives us some clues as to what types of activity are the most effective at reducing bowel cancer risk,” Mr Boyle says.  

The study found people who performed regular vigorous physical activity over their lifetime had a 40 per cent reduced risk of cancer of the distal (lower) colon and rectum. 

“These results suggest that vigorous activity like jogging, cycling, swimming, tennis, hockey, netball and football may be the most effective physical activities to lower the risk of bowel cancer,” Mr Boyle says. 

Of the possible mechanisms linking physical activity and colon cancer, there is evidence to suggest that obesity and vitamin D may have a great effect on distal colon cancer than proximal colon cancer. 

While the link between physical activity and colon cancers remains opaque, this study supports the suggestion that lifestyle factors are more strongly tied to distal colon cancer than proximal colon cancer.  

Another finding showed physical activity performed after the age of 51 years, may be more beneficial in reducing the risk of distal colon cancer than physical activity performed earlier in life. 

“This shows that it really is never too late to start being physically active,” Mr Boyle says. 

Author: Gina Ravenscroft | Source: Science Network/Western Australia [December 20, 2011]

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The new old age – today's pensioners are very different to yesterday's

Old people today have more sex, are more likely to be divorced, are cleverer and feel better, reveals a long-term research project comparing what it is like to be old today with 30 years ago. "It's time to start talking about the 'new old age'," says researcher Ingmar Skoog. 

The number of elderly is rising worldwide, and it is estimated that average life expectancy in Europe will reach 100 by the end of the century. 

At the same time, old age and what we expect from it are changing. An extensive research project at the University of Gothenburg's Sahlgrenska Academy has spent a number of years comparing the elderly of the 1970s with those of today. The project, known as the H70 study, reveals that old age has changed drastically in a number of ways. 

For example, the proportion of elderly with schooling beyond secondary level has risen from 14% to almost 40% for both genders. This is reflected in a better performance in intelligence tests by today's 70-year-olds than their counterparts back in the 1970s. 

The proportion of married people has increased, as has the proportion of divorcees. The elderly are also now more sexually active, and the number with sexual problems such as impotence has fallen. 

The results of the long-term study can also be contradictory, not least when it comes to social networking: 

"The H70 study shows that the elderly are more outgoing today than they were in the 1970s – they talk more to their neighbours, for example – yet the percentage of elderly who feel lonely has increased significantly," says professor Ingmar Skoog from the University of Gothenburg's Sahlgrenska Academy, who leads the study. 

Old people's mental health does not seem to have changed, however. Dementia disorders are no more prevalent today than they were 30 years ago, and while more old people consider themselves to be mildly depressed, more severe forms of depression have not become more common. Meanwhile the elderly are coping better with everyday life: the number needing help with cleaning has fallen from 25% to 12%, and only 4% need help taking a bath, down from 14% in the 1970s. 

"Our conclusion is that pensioners are generally healthier and perkier today than they were 30 years ago," says Skoog. "This may be of interest both in the debate about where to set the retirement age and in terms of the baby boomers now hitting retirement age." 

The H70 study in Gothenburg began back in 1971. More than 1,000 70-year-old men and women born in 1901-02 were examined by doctors and interviewed about their lives to obtain a picture of diseases in elderly populations, risk factors and their functional capacity and social networks. The participants were examined again at the age of 75 and then at regular intervals until the final participant died at the age of 105. The year 2000 brought the start of a new study of 70-year-olds born in 1930, who were examined using the same methods, making it possible to follow a specific generation through life and compare different generations.  

Source: University of Gothenburg [October 31, 2011]

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Targeting leg fatigue in heart failure

Doctors should not only treat the heart muscle in chronic heart failure patients, but also their leg muscles through exercise, say researchers in a major new study. 

Heart failure causes breathlessness and fatigue that severely limits normal daily activities such as walking. The University of Leeds research team has, for the first time, shown that leg muscle dysfunction is related to the severity of symptoms in heart failure patients. These findings suggest that daily activity in patients with severe heart failure may not simply be limited by the failing heart, but also by an impairment in the leg muscles themselves. 

In a series of experiments with chronic heart failure patients, the research team measured responses of the heart, lungs and leg muscles following a moderate exercise warm-up. Using a near-infrared laser to measure the oxygenation of the leg muscles, they found that warm-up exercise increased the activity of skeletal muscle enzymes that control energy production. However, this adaptation was less in patients with the most severe symptoms, showing that the heart failure condition had a negative impact on the normal function of the leg muscles. 

Dr Harry Rossiter, of the University's Faculty of Biological Sciences says: "Many chronic heart failure patients complain of leg fatigue during exercise and this can prevent them from being active. Our study shows that by warming up properly, patients can improve the oxygenation and performance of their leg muscles, which is beneficial in promoting exercise tolerance." 

"When your muscles don't use oxygen well, it causes an uncomfortable burning sensation during activity," says Dr Klaus Witte, the Leeds General Infirmary Cardiologist on the research team. "The effect of a warm up is to direct oxygen to the places that are going to need it, and make the muscles ready to use it when you start exercising." 

Dr Rossiter says the next stage of this research will be to see whether training of the skeletal muscles can improve long-term overall outcomes for patients with chronic heart failure, and to discover more about the pathological changes in the leg muscles that may be a contributing factor in limiting exercise. 

"Our main message is that exercise is safe and beneficial in patients with heart failure. By warming up the leg muscles properly, the exercise can be more comfortable and sustained for longer - affording great benefits for these patients," he says.  

Source: University of Leeds [October 31, 2011]

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Yoga aids chronic back pain sufferers

Yoga can provide more effective treatment for chronic lower back pain than more conventional methods, according to the UK's largest ever study into the benefits of yoga. 

The study, led by the University of York and funded by Arthritis Research UK, found that people offered a specially-designed 12-week yoga programme experienced greater improvements in back function and more confidence in performing everyday tasks than those offered conventional forms of GP care. 

The research focused on back function – people's ability to undertake activities without being limited by back pain, which was measured using the Roland Morris Disability Questionnaire. Although improvements in back function were more pronounced at three months, researchers found there was still an improvement in people's ability to perform tasks such as walking more quickly, getting dressed without help or standing up for longer periods of time even nine months after the classes had finished. 

The trial involved two groups of people who were both receiving GP care for chronic or recurrent back pain. A 156-strong group were offered group yoga classes specially designed to improve back function, while a second control group of 157 people were offered GP care alone. 

The findings of the study, which was carried out by researchers from the Department of Health Sciences at the University of York and the Hull York Medical School, are published in the Annals of Internal Medicine this week. 

Lower back pain is a common episodic condition, with 80 per cent of the UK population suffering from it at some point in their lives. It is estimated that around 4.9 million working days a year are lost due to back pain. However, few effective, evidence-based treatments exist. 

The yoga programme, which involved 20 experienced yoga teachers, was designed and delivered by Truro-based Alison Trewhela, an Iyengar Yoga teacher and Senior Practitioner in Yoga on the British Register of Complementary Practitioners, in collaboration with York-based yoga teacher Anna Semlyen, a Back Care Advisor to the British Wheel of Yoga. 

The classes were designed for complete beginners, with yoga teachers given extra training in back care. Participants were recruited from 39 general practices in seven Primary Care Trust areas, with classes held in non-NHS premises in Cornwall, North London, West London, Manchester and York. 

Chief Investigator Professor David Torgerson, Director of York Trials Unit, in the University's Department of Health Sciences, said: "Back pain is an extremely common and costly condition. Exercise treatment, although widely used and recommended, has only a small effect on back pain. We therefore set out to investigate an alternative approach using a specially-developed weekly yoga programme for back pain sufferers to see if this allowed them to manage their back pain more successfully. 

"While previous studies have focused on the short-term benefits of yoga, we also wanted to see the long-term effects and measured improvements three, six and 12 months after entry into the study. Our results showed that yoga can provide both short and long-term benefits to those suffering from chronic or recurrent back pain, without any serious side-effects." 

Medical Director of Arthritis Research UK Professor Alan Silman said: "We're delighted that our trial has shown that yoga provides such positive benefits for people with chronic low back pain. This extremely common condition cannot be managed with painkillers alone and there is an urgent need to have non-drug therapies that sufferers can utilise in their own home. This trial is part of our larger commitment to seek self-help solutions to this common musculoskeletal problem. There are compelling explanations why yoga may be helpful and this trial lends powerful support to the wider use of this approach." 

Trial participants completed a questionnaire at three, six and 12 months from the start of the programme. On average, members of the yoga group were able to undertake 30 per cent more activities compared with those in the usual care group after three months, a statistically significant difference between the two groups which has been recognised as clinically important. 

The trial showed that there was more reduction in pain in the yoga group than the usual care group, but of marginal statistical significance. 

Researchers also compared the results from the yoga programme with those for high-quality randomised trials for exercise and manipulation, the Alexander technique and cognitive-behavioural treatment. The results suggested that the 12-week yoga group programme may improve back function more than exercise and manipulation, cognitive-behaviour treatment and six sessions of 1-to-1 Alexander technique, but not as much as 24 sessions of 1-to-1 Alexander technique. 

Trial participant Sue Faulkner, 68, retired from her job as an administrator four years ago with the intention of spending her time gardening. However, within six months of retiring her back was so bad she found that walking any distance was painful and she needed to stop regularly to rest. Gardening was out of the question. 

Sue from Bishopthorpe in York said: "I felt a definite benefit after the programme as it made me more flexible and we were taught positions to relieve certain types of back pain. I've continued going to yoga classes and still do the positions I was taught during the 12-week programme. Walking around is no longer a problem and I can do my gardening now so long as I pace myself. I've even taken on an allotment with my daughter and son-in-law and no longer take pain killers." 

Those attending the specially-designed yoga programme, which involved step-by-step gentle classes, were encouraged to become self-sufficient in the long-term. Classes were supported with four home practice sheets, a manual, and a four-track audio CD teaching how to relax physically and mentally. 

Iyengar Yoga teacher Alison Trewhela said: "The yoga programme offers poses for pain-relief and mental calming; mobilising, stretching, strengthening and relaxation; improving awareness of posture; education about how a healthy back functions; and positive mental focus. Yoga aims to treat the whole person – not just the physical. 

"As most back pain conditions recur, these lifelong self-management skills are likely to be useful as a preventative measure. As a result of smaller previous trials, one million Americans currently practise yoga as a recommended treatment for low back pain." 

Participants in the yoga programme were surveyed nine months after classes had finished and more than half of those who responded were still regularly practising yoga, mostly at home, twice a week.

Source: University of York [October 31, 2011]

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