The truth is that no medication or supplement even comes close to exercise for being able to do so much for so many people -- or probably ever will.
While we've all heard that regular exercise can improve heart health and strengthen muscles, it can also enhance the quality of your life in a number of ways. Five such benefits may surprise you.
The headline of a survey by the National Sleep Foundation said it best: "Exercise is good for sleep." In the poll of 1,000 people
, those who exercised the most vigorously reported the best sleep quality overall. And they were less likely than non-exercisers to say that in the past two weeks, they had experienced problems such as trouble falling asleep or waking during the night.
These findings are supported by a review of 66 studies
on exercise and sleep. It concluded that regular exercise is comparable to sleep medication or behavioral therapy in improving the ability to fall asleep, as well as sleep duration and quality.
Researchers aren't sure why, but they suspect that physical activity may help by affecting body temperature, metabolic rate, heart rate or anxiety level, among other things.
Because exercise also revs up your body, conventional wisdom has it that exercising in the evening can interfere with sleep. But research in young adults
as well as older people
has failed to support this assertion.
Of course, everyone is different, so it's possible that nighttime exercise may make it harder for you to sleep. But the only way to know is to try. You may be pleasantly surprised at what a little pre-bedtime sweat can do for your sleep.
You may have heard fitness buffs claim that they never get sick. This may seem like baseless -- not to mention annoying -- boasting, but there is scientific truth to it. Numerous studies have linked regular exercise to a lower risk of colds.
For example, a study that followed 1,000 adults for three months found that those who did aerobic exercise at least five days a week were about half as likely to develop colds as those who didn't exercise
. And when exercisers did catch colds, they had fewer and less severe symptoms than their couch-potato peers.
These studies, which show associations but not cause and effect, are corroborated by randomized trials on exercise and colds. In one such experiment, sedentary postmenopausal women were assigned either moderately intense exercise (such as brisk walking) five days a week or once-a-week stretching. By the final three months of the 12-month study, those doing regular exercise reported having substantially fewer colds than the stretchers
Research in animals and humans suggests that exercise chases away colds by boosting the immune system. At the same time, very intense activities may suppress immunity by increasing levels of the stress hormones cortisol and adrenaline.
That perhaps explains why, in one study, runners who participated in a Los Angeles marathon were nearly six times more likely to get sick in the week after the race
than runners who did not participate.
Though this is a potential issue for elite athletes or people who do marathons or triathlons, the level of activity among most exercisers -- even if it's vigorous -- is far more likely to keep colds at bay than bring them on.
When you hear about a connection between exercise and eyesight, maybe you picture those eye exercise programs that promise to sharpen your vision. But that's not what we're talking about. Instead of moving your eyes, the idea is to move your feet.
Research shows that people who are physically active have a lower risk of cataracts. For example, a study of nearly 50,000 runners and walkers found that those who exercised most vigorously were 42% less likely to develop cataracts
than those who exercised the least vigorously. Exercisers who fell in the middle in terms of intensity were also at reduced risk, though to a lesser degree.
The same researcher found a similar benefit regarding age-related macular degeneration
, a leading cause of vision loss also known as AMD, in a study of nearly 42,000 runners. The more people ran, the more their risk of the condition declined. A different study, which followed roughly 4,000 people for 15 years, showed that participants who were physically active were less likely to develop AMD
than those who weren't active.
Scientists aren't sure why exercise protects against cataracts and age-related macular degeneration. One possibility is that it reduces inflammation, which is associated with both conditions.
Cataracts and AMD have also been linked to risk factors for cardiovascular disease, including elevated blood sugar and triglycerides, which regular exercise can improve. Further, some research suggests that people who are overweight or obese are more prone to cataracts and AMD, so physical activity may help by preventing weight gain.
You heard it here first: Exercise may be good for your hearing. A study of more than 68,000 female nurses, who were followed for 20 years, found that walking at least two hours a week was associated with a lower risk of hearing loss
. Other research has linked higher fitness levels with better hearing
Exercise may protect against hearing loss by improving blood flow to the cochlea, the snail-shaped structure in the inner ear that converts sound waves into nerve signals that are sent to the brain. What's more, it may prevent the loss of neurotransmitters, which carry those signals between nerve cells. Exercise may also help by reducing the risk of diabetes and cardiovascular disease, both of which are linked to hearing loss.
Of course, blasting music into your ears while you exercise could have the opposite effect and do damage to your hearing. Noise-canceling headphones are a good option because they reduce the need to turn up your music as much. But don't use them while exercising on a busy road. By being unaware of approaching traffic, you could be subjecting yourself to a risk far more serious than loud music.
Better bathroom habits
The place to start, naturally, is No. 1: Though high-impact activities such as jumping or running can cause women to leak urine, research shows that moderate exercise may decrease the risk. For example, a study of middle-aged female nurses found that those who were physically active had lower rates of urinary incontinence
than women who were inactive. A study of older nurses by the same team of researchers yielded similar findings
A urinary problem familiar to many middle-aged and older men is nocturia, the need to get up more than once a night to pee. Often, the cause is an enlarged prostate, a condition known as benign prostatic hyperplasia. Exercise can help prevent nocturia or reduce its severity.
In a large study of men with benign prostatic hyperplasia, those who were physically active for an hour or more per week were less likely to report nocturia
than those who were sedentary. Likewise, a study of sedentary older men found that after eight weeks of daily walking, they urinated less frequently
during the night.
Another common bathroom-related problem for both men and women is constipation, which exercise can help improve as well. In a study of 62,000 women, those who reported daily physical activity were nearly half as likely to experience constipation
as women who exercised less than once a week. A randomized trial involving inactive middle-aged men and women with chronic constipation found that those assigned to a 12-week exercise program were able to poop more easily
Exercise helps by decreasing transit time. That's how long it takes food to move through the digestive tract -- not, as it sounds, the amount of time it takes to get to work. Alas, a shorter commute is one benefit that exercise may not have -- unless, of course, biking to work is faster for you than driving in heavy traffic.