Fitness - Swimming: A Sport For All Seasons
Swimming has myriad physical and psychological benefits at almost any stage or state of life.
In exercise, water is our natural ally. It lightens our load, stimulates our circulation, protects us from injury, and buoys our spirits. At the same time, it exerts just enough resistance to let us know we're doing some work. For that reason, it's no surprise that swimming is one of the most popular ways to retain -- or regain -- physical and psychological fitness.
HOW WATER WORKS FOR US
Archimedes' bathtub epiphany explains why we begin to reap benefits the moment we step into the pool. As the ancient Greek mathematician observed, the upward force on a submerged body is equal to the weight of the water the body has displaced. This force, which we know as buoyancy, makes us seem lighter in the water than on land. People whose bodies are less dense than water -- usually because they have a relatively high proportion of fat to muscle and bone -- will stay afloat with little effort required.
The pressure water exerts on submerged feet and legs massages blood upward through the veins, improving circulation. By cushioning the joints, water greatly reduces the likelihood of athletic injury; competitive swimmers suffer far fewer sports injuries than do athletes who compete on dry land. Water warmer than body temperature relaxes muscles; cooler water prevents overheating during strenuous exercise.
THE HEALTH BENEFITS OF SWIMMING
It stands to reason that swimming in a well-guarded, safe pool offers most of the benefits and few of the risks associated with other forms of aerobic and resistance exercise. Yet, while there are reams of data on the effects of high-intensity swimming on young, competitive athletes, few studies have looked at recreational or fitness swimmers.
Many of the observational studies that have shown the health benefits of aerobic exercise lump swimming together with walking, running, and cycling, although two studies published in 2008 did separate out swimming. In one that measured blood pressure, cholesterol levels, and other aspects of cardiovascular health, swimmers and runners had the best profiles. In the other, which tallied up the deaths that occurred among 40,000 men between the ages of 20 and 90 over a 13-year period, swimmers came out on top (only 2 percent of them died) compared with runners (8 percent), walkers (9 percent), and people who didn't exercise (11 percent).
The few data available indicate that swimming for 30 minutes to an hour three times a week does the following:
--Lowers blood pressure. Swimming, like other forms of moderate exercise, can also improve the heart's pumping function.
--Improves mood. Not only does swimming ward off the blues, water activities are on a par with yoga in quelling anxiety.
--Relieves arthritic symptoms. Swimming relieves pain and increases flexibility for people with arthritis and fibromyalgia.
--May promote weight loss. In studies, swimming hasn't fared well as a way to lose weight. But an hour of swimming burns 350 to 500 calories. That's less than the 420 to 590 calories you'd use up jogging for an hour, but it's still significant. And swimming is a good activity for people who are overweight because the water is supportive, so hips, knees, ankles, and feet aren't stressed.
As long as you don't add calories to your diet to compensate for the exercise, regular swimming should take weight off. And there's a positive feedback loop, because as swimmers lose weight, they become less buoyant and have to expend more energy to stay afloat, consuming even more calories in the process.
--Tones large muscle groups. Swimming strengthens not just the arms and legs, but also the back and abdominal muscles.
To move forward, swimmers must overcome the resistance of the water ahead, as well as the friction of the water flowing over them. They also have to contend with turbulence generated by other swimmers. Each of the basic strokes illustrated here has been studied and refined by physiologists to minimize resistance and maximize lift. The current technique might be a little different from the one you learned as a child, and you're likely to enjoy some strokes more than others.
As you pull your hand through the water, it should trace a modified S-shaped pattern.
Your pull should accelerate as it goes through the water. Finish strong.
Because the legs provide little propulsive force compared with the arms, a flutter kick, executed below the surface of the water, serves primarily to keep the hips up and to maintain balance. Don't splash.
Rotate your hips and trunk so you knife through the water. Swimming coaches often say the key to good crawl form is the hip motion.
Don't lift your head too far out of water. As you move forward, your head pushes water out of the way so there's room to breathe.
This is the least strenuous stroke for many people.
The frog kick can be difficult for people with knee or back problems. Slowing down the kick and reducing the "snap" can help.
Limit the sweep of the arms and hands. Many people extend their arms too far out from the body.
Ideally, your body should follow an up-and-down serpentine path in the water, with the head and trunk rising, followed by the lower half of the body.
Like the breaststroke, this is a less strenuous stroke. The Navy Seals use a version of the sidestroke (there's a flutter kick inserted between the scissor kicks) because it conserves energy.
Don't lift your head too high. Your cheek should be flat against the water.
The familiar "pick an apple, put it in the basket" motto for the hand and arm motion still works.
The elementary backstroke is like the breaststroke, but facing up instead of down, and the back crawl is the supine version of the crawl.
A backstroke makes breathing easier because your mouth and nose are free of the water, but it also means you can't see where you are going.
As with the crawl, one of the keys to the back crawl is rotating your trunk and hips.
In the back crawl, your arm should be bent at the elbow as you pull it back through the water. Many people mistakenly keep their arms straight.
FINDING A FACILITY
At this of year in northerly climes, most swimmers head inside to pools. In fact, many people who swim for fitness prefer the controlled circumstances of a pool, regardless of season. Since access to a pool often requires joining a health club or Y, it's a good idea to make a trial visit before you sign on. During you stopover, you should do the following:
--Make a quick inspection. The showers and changing area should be clean and well maintained; the pool and deck smooth, but not slippery; the pool water clear. You should be able to see any painted stripes on the bottom of the pool clearly.
--Talk to the staff. Find out when the last health inspection was performed and the grade the pool received. Ask about the rules and culture of the pool, particularly lap swimming etiquette.
--Take a whiff. The pungent aroma of chlorine shouldn't greet you. Mounting evidence has associated chlorine exposure with respiratory disease in competitive swimmers. Although some chlorine is still necessary to keep waterborne pathogens down, advances in purification have made it possible to greatly reduce chlorine levels.
--Listen up. Silence may be golden, but it means that the pool's pumping and filtration systems are off. They are the pool's heart and kidneys, and you should be able to hear them working.
--Test the waters. The water temperature should be fairly inviting. The best temperature for lap swimming is 80 degrees F, which will feel cool when you first get in but not after you have swum a lap or two. Pools used by young children are often kept at warmer temperatures that feel comfortable at first but won't once you start exercising.
--Eye the width. The lanes should be nice and wide; about 10 feet across is ideal. At a busy pool, you'll often need to share a lane, so room is important.
--Check into lessons. Even if you already know how to swim, a stroke improvement class can help you swim more efficiently and probably faster. If you aren't inclined to take lessons, you can ask a lifeguard to watch your stroke and offer suggestions for how you might improve it.
GETTING IN THE SWIM
The right gear and a well-planned workout are as essential in the pool as in the gym. Choose a suit that is snug, yet allows you to move easily. Goggles should fit tightly, so they don't leak, but without too much digging into your skin.
If you're prone to ear infections, a homemade solution, absorbent cotton coated in petroleum jelly, has been shown to be a more effective water barrier than commercial ear plugs.
A fitness swim follows the arc of any good workout -- five to 10 minutes of warm-up, 20 to 40 minutes of peak effort, and five to 10 minutes to cool down. Here are a few exercises for warming up or cooling down outside the pool:
Trunk twist. With your hands on your hips, twist to your right and then your left at the waist.
Shoulder stretch. Bend your right arm at the elbow at ear level. Reach your right hand down the center of your back as far as you can. Release. Repeat with the left arm.
Overhead stretch. Reach as high as you can with both hands meeting above your head. Bend at the waist and stretch from side to side.
Leg stretch. Extend your right leg straight behind you, heel flat on the ground. Bend your left knee and lean forward. Switch legs and repeat. - Harvard Health Letter
The Official Mayo Clinic Diet Program
Donald Hensrud, M.D.
Physicians and researchers at Mayo Clinic have developed a dietary program that we can endorse. We believe there's enough evidence in the scientific literature and enough experience with it here at Mayo Clinic that we feel comfortable putting Mayo's name on this program. This is the official Mayo Clinic Diet.
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(c) 2009 Harvard Health Letters