Exercise and Immunity

Battling another cough or cold? Feeling tired all the time? Taking a daily walk or following a simple exercise routine a few times a week may help you feel better.

Exercise helps decrease your chances of developing heart disease and keeps your bones healthy and strong.

We don’t know exactly if or how exercise increases your immunity to certain illnesses, but there are several theories (none of these theories have been proven). Some of them are:

  • Physical activity may help flush bacteria out of the lungs and airways. This may reduce your chance of getting a cold, flu, or other airborne illness.
  • Exercise causes changes in antibodies and white blood cells (the body’s immune system cells that fight disease). These antibodies or white blood cells circulate more rapidly, so they could detect illnesses earlier than they might have before. However, no one knows whether these changes help prevent infections.
  • The brief rise in body temperature during and right after exercise may prevent bacteria from growing. This temperature rise may help the body fight infection more effectively. (This is similar to what happens when you have a fever.)
  • Exercise slows down the release of stress-related hormones. Some stress increases the chance of illness. Lower stress hormones may protect against illness.

Although exercise is good for you, be careful not to overdo it. People who already exercise regularly should not exercise more intensely just to increase their immunity. Heavy, long-term exercise (such as marathon running and intense gym training) could actually decrease the amount of white blood cells circulating through the body and increase stress-related hormones.

Studies have shown that people who go from a sedentary (“couch potato”) lifestyle to a moderately energetic lifestyle benefit most from starting (and sticking to) an exercise program. A moderate program can consist of:

  • Bicycling with your children a few times a week
  • Taking daily 20 – 30 minute walks
  • Going to the gym every other day
  • Playing golf regularly

Exercise can help you feel better about yourself, just by making you feel healthier and more energetic. So go ahead, take that aerobics class or go for that walk. You’ll feel better and healthier for it.

There is no strong evidence to prove that taking immune supplements along with exercising lowers the chance of illness or infections.

Source: U.S. National Library of Medicine


Exercise: Good or bad for immunity?

Regular exercise is one of the pillars of healthy living. It improves cardiovascular health, lowers blood pressure, helps control body weight, and protects against a variety of diseases. But does it help maintain a healthy immune system? Just like a healthy diet, exercise can contribute to general good health and therefore to a healthy immune system. It may contribute even more directly by promoting good circulation, which allows the cells and substances of the immune system to move through the body freely and do their job efficiently.

Some scientists are trying to take the next step to determine whether exercise directly affects a person’s susceptibility to infection. For example, some researchers are looking at whether extreme amounts of intensive exercise can cause athletes to get sick more often or somehow impairs their immune function. To do this sort of research, exercise scientists typically ask athletes to exercise intensively; the scientists test their blood and urine before and after the exercise to detect any changes in immune system components. While some changes have been recorded, immunologists do not yet know what these changes mean in terms of human immune response.

But these subjects are elite athletes undergoing intense physical exertion. What about moderate exercise for average people? Does it help keep the immune system healthy? For now, even though a direct beneficial link hasn’t been established, it’s reasonable to consider moderate regular exercise to be a beneficial arrow in the quiver of healthy living, a potentially important means for keeping your immune system healthy along with the rest of your body.

One approach that could help researchers get more complete answers about whether lifestyle factors such as exercise help improve immunity takes advantage of the sequencing of the human genome. This opportunity for research based on updated biomedical technology can be employed to give a more complete answer to this and similar questions about the immune system. For example, microarrays or “gene chips” based on the human genome allow scientists to look simultaneously at how thousands of gene sequences are turned on or off in response to specific physiological conditions — for example, blood cells from athletes before and after exercise. Researchers hope to use these tools to analyze patterns in order to better understand how the many pathways involved act at once.

Source: Harvard Health Publication


Read more:

How Much Exercise is too Much? Ask your Immune System . . . . .

Exercise, Healthy Diet Can Give Your Immune System a Boost . . . . .

Exercise Could Boost The Immune System, Study Suggests . . . . .

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An Hour of Moderate Exercise a Day Enough to Counter Health Risks from Prolonged Sitting

The health risks associated with sitting for eight or more hours a day – whether at work, home or commuting – can be eliminated with an hour or more of physical activity a day, according to a study from an international team of researchers.

Ever since a study back in 1953 discovered that London bus drivers were at greater risk of heart disease compared to bus conductors, scientists have found increasing evidence that lack of physical activity is a major risk factor for several diseases and for risk of early death. Recent estimates suggest that more than 5 million people die globally each year as a result of failing to meet recommended daily activity levels.

Studies in high-income countries have suggested that adults spend the majority of their waking hours sitting down. A typical day for many people is driving to work, sitting in an office, driving home and watching TV. Current physical activity guidelines recommend that adults do at least 150 minutes of moderate intensity exercise per week.

In an analysis published today in The Lancet that draws together a number of existing studies, an international team of researchers asked the question: if an individual is active enough, can this reduce, or even eliminate, the increased risk of early death associated with sitting down?

In total the researchers analysed 16 studies, which included data from more than one million men and women. The team grouped individuals into four quartiles depending on their level of moderate intensity physical activity, ranging from less than 5 minutes per day in the bottom group to over 60 minutes in the top. Moderate intensity exercise was defined as equating to walking at 3.5 miles/hour or cycling at 10 miles/hour, for example.

The researchers found that 60 to 75 minutes of moderate intensity exercise per day were sufficient to eliminate the increased risk of early death associated with sitting for over eight hours per day. However, as many as three out of four people in the study failed to reach this level of daily activity.

The greatest risk of early death was for those individuals who were physically inactive, regardless of the amount of time sitting – they were between 28% and 59% more likely to die early compared with those who were in the most active quartile – a similar risk to that associated with smoking and obesity. In other words, lack of physical activity is a greater health risk than prolonged sitting.

“There has been a lot of concern about the health risks associated with today’s more sedentary lifestyles,” says Professor Ulf Ekelund from the Medical Research Council Epidemiology Unit at the University of Cambridge. “Our message is a positive one: it is possible to reduce – or even eliminate – these risks if we are active enough, even without having to take up sports or go to the gym.

“For many people who commute to work and have office-based jobs, there is no way to escape sitting for prolonged periods of time. For these people in particular, we cannot stress enough the importance of getting exercise, whether it’s getting out for a walk at lunchtime, going for a run in the morning or cycling to work. An hour of physical activity per day is the ideal, but if this is unmanageable, then at least doing some exercise each day can help reduce the risk.”

The researchers acknowledge that there are limitations to the data analysed, which mainly came from participants aged 45 years and older and living in western Europe, the US and Australia. However, they believe that the strengths of the analysis outweigh these limitations. Most importantly, the researchers asked all included studies to reanalyse their data in a harmonized manner, an approach that has never before been adopted for a study of this size and therefore also provides much more robust effect estimates compared with previous studies.

Source: University of Cambridge


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Can You Get the Benefits of Exercise by Having A Hot Bath?

Michael Mosley wrote . . . . .

Having a hot bath or a sauna is a good way to soothe your limbs after exercise, but what happens if you do it instead of exercise? Dr Steve Faulkner of Loughborough University asked me to take part in an experiment comparing the relative benefits of having a long, hot bath versus an hour of hard pedalling.

For this study I join a group of volunteers who have all been fitted with monitors which continuously record blood sugar levels. Keeping your blood sugar levels within the normal range is an important measure of your “metabolic” fitness.

We are also fitted with equipment to measure how many calories we burn and rectal thermometers to constantly measure our internal, core temperature.

The first part of the experiment is very relaxing, consisting of having a long, hot bath.

While I sit in the bath, which they keep at 40C, Steve closely monitors my core temperature. Once it has risen and stayed there, I am allowed out.

A couple of hours after my bath I have a light meal.

Since we want to see how having a hot bath compares with exercise we repeat the experiment, except this time instead of a bath it’s an hour’s sweating on a bike.

So what’s the result?

“One of the first things that we were looking at,” Steve says, “is the energy expenditure while you’re in the bath and what we found was an 80% increase in energy expenditure just as a result of sitting in the bath for the course of an hour.”

This is nothing like as many calories as cycling for an hour (which comes out at an average of 630 calories) but we do burn 140 calories, the equivalent of a brisk 30-minute walk.

But what about our blood sugar levels?

“Where we started to see differences,” Steve tells me, “was when we looked at your peak glucose output.”

Your peak glucose output is the amount that your blood sugar goes up after a meal. It’s a risk marker for type-2 diabetes and other metabolic diseases.

“What we found,” Steve says, “was that peak glucose was actually quite a bit lower after the bath, compared with exercise, which was completely unexpected”

In fact our volunteers’ post-meal glucose levels are, on average, 10% lower after the baths than after the exercise.

But why does this happen?

Steve thinks that it may be partly due to the release of heat shock proteins which are, as the name implies, proteins released in response to heat. Their release can also be triggered by other forms of stress, such as infection, inflammation and exercise,

Heat shock proteins are part of your defence system. They help protect your body against damage, but animal studies suggest they may also help divert sugar from the bloodstream and into muscles. Keeping blood sugar levels down is important because persistently high blood sugar damages arteries and nerves.

Steve wouldn’t suggest that having a hot bath or sauna should replace doing exercise and he recommends that people try to do at least 150 minutes of moderate-intensity exercise a week. He sees this “whole body heating” research as being potentially most useful for people who struggle with controlling their blood sugar levels and who find it hard to exercise.

So getting hot turns out to have surprising benefits . But what about doing something called motor imagery? Can simply imagining yourself doing a particular exercise make your muscles stronger?

Motor imagery is not a crazy as it sounds. It’s widely used by top athletes. To find out what effects it would have on a group of relatively sedentary Trust Me viewers we ask Prof Tony Kay from the University of Northampton to do an experiment.

He starts by taking some base measurements. These include testing how strong their calf muscles were by asking them push as hard as they could against a heavy plate linked to sensors. Next he uses ultrasound to measure their calf muscle size. Finally, to assess just how much of their muscle they are actually using when pushing as hard as possible, he gives these muscles a small electric shock.

Once he’s got his baseline measurements Tony asks the volunteers to spend 15 minutes a day thinking about the pushing exercise they’ve just done, imagining doing it.

So what happens? Well, much to my surprise, just thinking about exercising their calf muscle really does improve their strength. When we repeat the test a month later the group’s calf muscles are, on average, 8% stronger.

It isn’t because their muscles have got bigger (they haven’t) – it’s because by the end of a month of thinking about a particular exercise they are using more of the muscle fibres than they did at the start.

“They got better at recruiting the muscles in an orderly fashion,” Tony says, “so they could activate a larger percentage of the muscle. That produced more force and so they became stronger.”

Tony thinks that as well as helping top athletes, mental imagery could be a useful way to avoid losing strength if you’re injured and can’t exercise.

Source: BBC

Diet Tops Exercise for Cutting Weight, Cancer Risk, New Study Shows

Whether cutting pounds or cancer risk, the crunches in your salad trump the crunches in your workout, say scientists at Fred Hutchinson Cancer Research Center.

That finding emerged in a new study of overweight and obese women who significantly lowered their weight – and levels of proteins associated with cancer – by slashing daily calories or by improving both diet and exercise.

Similar-sized women who exercised regularly but maintained their usual calorie intake did not post big drops in pounds or in those suspect proteins, reports the Fred Hutch study, published in Cancer Research, a journal of the American Association for Cancer Research.

“The fact that exercise alone had little effect was … surprising,” said Dr. Catherine Duggan, study co-leader and principal staff scientist in the Public Health Sciences Division at the Hutch.

“Many people still think they just need to exercise a little more and they’ll lose a lot of weight. Doesn’t happen,” said Dr. Anne McTiernan, the article’s senior author and a cancer prevention researcher at the Hutch.

The scales of the women studied revealed the power of portion over perspiration:

  • Women who followed the weight-loss diet – a daily calorie goal based on starting weight and a reduction of fat to less than 30 percent of total calories – lost, on average, 8.5 percent of their starting weight after one year.
  • Those who followed that diet while exercising moderately to vigorously for 45 minutes a day, five days a week lost, on average, a bit more – 10.8 percent of their weight after a year.
  • But those who stuck to that exercise plan while not curtailing their calories lost, on average, only 2.4 percent of their weight when the year had elapsed. (Most women will not gain a significant amount of muscle mass with exercise, said McTiernan.)

The study enrolled 439 women from the Seattle area who were randomly placed into one of four groups – exercise only, diet only, exercise plus diet, or no change to health habits. The women were aged 50 to 75, sedentary, postmenopausal, and either overweight or obese but otherwise healthy.

“We know that being overweight and having a sedentary lifestyle is associated with an increase in risk for developing certain kinds of cancer. However, we don’t know exactly why,” Duggan said.

That’s where the three proteins examined by Duggan and McTiernan may offer clues.

Blood samples were collected from the study participants at the trial’s start. In each of those samples, researchers measured three proteins – VEGF, PAI-1 and PEDF – that flow through the body and help in the formation of new blood vessels, a process called angiogenesis.

That mechanism can boost the body in tiny or crucial ways, such as amid wound healing. But angiogenesis – a sprouting of fresh blood vessels to carry oxygen and nutrients – also occurs during the growth of tumors. The three measured proteins are involved in nurturing the growth and survival of cancer cells.

Judy Casey, 72, was a trial participant who was part of the exercise-only group. She was motivated to enroll, she said, because her mother, Marion, was diagnosed with breast cancer and died of thyroid cancer in 1999 at age 79.

“I’ve never been a large person but I found that I walked taller (from exercising), that it improved my physical and emotional health,” said Casey, who lost between 5 and 8 pounds during the study.

The women who adhered for one year to the caloric restriction and lower-fat eating – or a combination of the diet and workout plans – had significantly decreased levels of those angiogenesis-related proteins, the study found.

Those same women met regularly with dietitians who helped them infuse their menus and dining habits with more fruits and vegetables, better portion control, daily weighing and food journaling.

Lower levels of the cancer-associated proteins were not found in the women who participated in the exercise-only group, the study showed.

The Hutch researchers cannot currently say that when someone loses weight and lowers their levels of angiogenic-related proteins it definitively decreases that person’s likelihood of a cancer diagnosis.

But the findings do add to a growing body of evidence showing the link between being overweight and having elevated levels of certain proteins associated with a higher cancer risk, Duggan said.

The National Cancer Institute and the Breast Cancer Research Foundation funded the study.

The authors say they would advise sedentary, overweight, older adults to perhaps use the findings as a motivation to improve their diets and add more cardio.

“It’s never too late to adopt a health lifestyle that can lower risk factors for cancer,” McTiernan said.

Adults who have a stable, healthy body mass index (less than 25) don’t need to restrict calories, McTiernan added.

“Regardless of whether weight loss is a goal, exercise at any level is beneficial for many health effects,” Duggan said. “However, diet is the most effective method to achieve weight loss.”

Participant Judy Casey said that since the study ended she has worked to maintain her routine of brisk, three-mile walks in her Seattle neighborhood, she said.

“The findings are interesting. I’m always telling myself: you cannot eat cookies for breakfast. And the exercise, well, I don’t think it ever becomes easy. The people who say, ‘If I don’t run I get crazy,’ I would like to be able to say that about my walking,” Casey said. “Walking is still my thing. But I would always like to say I had a lot of fruits and vegetable today.”

Source: Fred Hutchinson Cancer Research Center


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Pumping Iron: Lighter Weights Just As Effective As Heavier Weights to Gain Muscle, Build Strength

New research from McMaster University is challenging traditional workout wisdom, suggesting that lifting lighter weights many times is as efficient as lifting heavy weights for fewer repetitions.

It is the latest in a series of studies that started in 2010, contradicting the decades-old message that the best way to build muscle is to lift heavy weights.

“Fatigue is the great equalizer here,” says Stuart Phillips, senior author on the study and professor in the Department of Kinesiology. “Lift to the point of exhaustion and it doesn’t matter whether the weights are heavy or light.”

Researchers recruited two groups of men for the study—all of them experienced weight lifters—who followed a 12-week, whole-body protocol. One group lifted lighter weights (up to 50 per cent of maximum strength) for sets ranging from 20 to 25 repetitions. The other group lifted heavier weights (up to 90 per cent of maximum strength) for eight to 12 repetitions. Both groups lifted to the point of failure.

Researchers analyzed muscle and blood samples and found gains in muscle mass and muscle fibre size, a key measure of strength, were virtually identical.

“At the point of fatigue, both groups would have been trying to maximally activate their muscle fibres to generate force,” says Phillips, who conducted the work with graduate students and co-authors Rob Morton and Sara Oikawa.

While researchers stress that elite athletes are unlikely to adopt this training regime, it is an effective way to get stronger, put on muscle and generally improve health.

“For the ‘mere mortal’ who wants to get stronger, we’ve shown that you can take a break from lifting heavy weights and not compromise any gains,” says Phillips. “It’s also a new choice which could appeal to the masses and get people to take up something they should be doing for their health.”

Another key finding was that none of the strength or muscle growth were related to testosterone or growth hormone, which many believe are responsible for such gains.

“It’s a complete falsehood that the short-lived rise in testosterone or growth hormone is a driver of muscle growth,” says Morton. “It’s just time to end that kind of thinking.”

Researchers suggest, however, that more work remains to be done in this area, including what underlying mechanisms are at work and in what populations does this sort of program work.

The findings are published online in the Journal of Applied Physiology.

Source: McMaster University


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