Americans spend a lot of money on yoga: $5.7 billion a year on yoga classes, equipment, clothing, vacations and things like DVDs, books and magazines, according to a survey by Yoga Journal. Why do so many people spend all that time and money learning to put themselves in unusual positions as they concentrate on each breath and try to free their minds?
They do it for their well-being. National health surveys have found that about 10 million people who practice yoga say they do it for their health. Another 2.5 million people who practice tai chi -- slow, meditative movements emphasizing breathing and balance -- or qigong, similar to tai chi, say the same thing. They do it either in the belief it will relieve existing aches, pains, disease symptoms or mental anguish, or because they believe it will help them maintain their good health.
Keeping Healthy People Healthy
Combining movement with meditative practices can help protect your good health -- but let common sense control expectations and don't, for example, expect reverses in disease or other miraculous results from so-called Eastern exercise practices.
As with any physical effort, you must practice correctly, safely and in accord with your own ability. There's no doubt that practicing yoga can increase flexibility. A small study of 10 healthy people, none of whom had any experience with yoga, found that after an eight-week training program, all their knees, elbows, ankles and shoulders were more flexible. In fact, any body part that could flex got better at it by objective measures. But the same study failed to show any improvements on treadmill tests or pulmonary function. And no one lost weight or inches around the waistline. If it seems to you that many yoga or tai chi practitioners are skinny, it's probably because they were thin to begin with.
Maybe it's that increased flexibility that allows yoga to ease back pain. And it can, indeed, do that, as researchers found when they studied 228 adults with chronic low-back pain. They divided the volunteers into three groups and gave one group 12 weeks of training in yoga; another group got 12 weeks training in conventional stretching exercises; and the final group received advice and pamphlets on how to exercise to care for their bad backs. Not surprisingly, the pamphlet group did the worst. But the yoga and stretching groups got relief from their pain at equal levels, leading researchers to speculate that it was yoga's muscle strengthening and stretching aspects that helped, rather than the meditation component.
However, don't expect a routine involving meditation and gentle movements to give you the cardiovascular benefits of even a moderately brisk walk at say, 3.5 miles per hour. When researchers monitored the heart rates of 26 women performing a 30-minute hatha yoga routine consisting of lying, sitting and standing postures, or asanas, they found the intensity to be too low to provide any cardiovascular benefit. Aerobically, you'll do your heart more good by shunning the elevator and using the stairs or parking at the far end of the shopping mall lot -- in general, by increasing the amount of time you're out of a chair and moving.
Stress Control
But aerobic exercise isn't the only way to protect your heart. Reducing stress and lowering blood pressure also may be protective and it is here that disciplines like yoga have shown their value. Yoga has been found to reduce anxiety among medical students just prior to their exams. It was shown to lift depression and ease anxiety in people who were caregivers to dementia patients.
Yoga may reduce inflammation, a marker increasingly seen as associated with all sorts of bad health outcomes: heart disease, arthritis, Alzheimer's disease, gum disease, osteoporosis -- even cancer. The mechanism for reducing inflammation may be related to stress reduction. In one study, for example, women who practiced yoga regularly for at least two years were compared to women who were just starting yoga. They found the novices' blood had 41% higher levels of a stress-related compound, cytokine interleukin 6, thought to play a role in heart disease and diabetes. They also found that the novices had levels of a marker for inflammation called C-reactive protein -- it's also associated with heart disease -- that was five times higher than that of the yoga experts. It could be researchers speculated that yoga's protective effects kick in after months or years of practice.
Sex
Can yoga improve your sex life? Some practitioners tout things like increased sexual arousal as a side effect of yoga. Maybe, but the evidence is quite weak. Some of the studies, such as one involving 40 women aged 22 to 55, are nothing more than questionnaires given before and after a few weeks in a yoga program. They may be interesting but they're not good science. Another small, non-randomized sexuality study looked at 68 men who experienced premature ejaculation: 30 men received treatment with the antidepressant Prozac while another 38 men practiced yoga for an hour each day. In the Prozac group, 25 of the 30 men showed improvement, and in the yoga group all 38 men reported improvements. In both groups, the improvements were noted both in self reports and corroborated by their wives, who were holding stopwatches during sexual encounters (not recommended as a way to reduce performance anxiety). Many studies of yoga and sexuality are fraught with design errors including small sample sizes, lack of randomization, or absence of a true control group of people who are not in yoga classes
Yoga, Tai Chi and Serious Disease
Can yoga be medically therapeutic? Can any meditative discipline go further than helping to keep already healthy people on the right track? Can these programs have an impact on disease?
Overpromising results from yoga, tai chi or any discipline to people who are seriously ill can be downright cruel. People with hard-to-control epilepsy, for example, might hope that because yoga can decrease stress and increase relaxation, it might influence the nervous system enough to control seizures. For instance, an evidenced-based review of studies of patients with epilepsy has found that, so far, no evidence exists that practicing yoga can reduce the number or duration of seizures in people with epilepsy.
The news can be moderately better when it comes to the ability of yoga and tai chi to help people maintain their balance, reduce fatigue or improve stamina. People of any age can be klutzes, tripping up a stair or over a curb. When we're young, we pick ourselves up and start over. But when older people have trouble keeping their balance, a resulting fall could have a domino effect of broken bone, hospitalization, nursing home and even death. A review of 15 studies showed that both yoga and tai chi helped people older than 60 with their capacities to more quickly stand up, walk 10 feet, turn around, walk back and sit down again -- a very good thing for long-term health.
People with Parkinson's disease slowly lose muscle control, experiencing greater difficulty walking and moving as the degenerative disease progresses. So again it was good news when a randomized, controlled study released last month in the New England Journal of Medicine found that tai chi helped Parkinson's patients show modest improvement in maintaining their balance and reduced falls. And people with the degenerative disease multiple sclerosis and who practice yoga have been shown to have lower levels of fatigue; yoga has no apparent effect on the loss of cognitive function that can accompany the disease.
Balance, Relaxation and Tranquility are not Competitive Goals
For healthy people and devotees of the latest trends in exercise, descriptions of a practice that combines terms like power and yoga have become familiar. But think about this: It's something of an oxymoron, akin to competitive relaxation or extreme meditation. In each case, the adjective can't help but contradict the noun.
After all, in addition to good health, the goals of meditative disciplines include tranquility and spiritual insight. As I understand them, neither yoga nor tai chi were meant to be Western-style sports, sweaty, cardio-pumping, testosterone-thumping, endurance- and muscle-building pastimes. When these traditionally gentle moves are pushed to extremes of haste, musculoskeletal deployment and other stresses on the body, its unsurprising practitioners may experience injuries.
Such injuries, specifically resulting from yoga, have been the subject of a kerfuffle recently, prompted by an excerpt of the book, The Science of Yoga: The Risks and Rewards, published in the New York Times Magazine, and written by science writer William J. Broad. Broad documents some horrible mishaps that have resulted from pushing yoga positions too far and too hard: torn ligaments, broken ribs, injuries requiring hip replacement surgery, spinal injuries -- even strokes and brain damage from bending the neck at unnatural angles while applying excess pressure.
So let me remind you that when doing any kind of exercise, all things in moderation. Build up strength and flexibility slowly, pay attention when your body's pain signals are pleading with you to stop, and, especially if you're an older adult, talk to your physician about a fitness plan. As with any exercise routine, use common sense. After all, jogging may be good for you, but that doesn't mean you should tackle a 100-mile run in the desert.