It may seem ironic, given that human beings are land dwellers, that one of the most comprehensive and effective forms of exercise we know involves dunking ourselves into an alien environment. Humans are not naturally designed to swim very efficiently, unlike penguins, sharks, seals and Michael Phelps. This, however, is exactly what makes it such a powerful fitness tool. Exercise—effective exercise, at any rate—must necessarily take your body out of its comfort zone, and swimming achieves this quite literally.
Winning stroke: Michael Phelps set a world record with eight golds at the Beijing Olympics in 2008. AFP
It is also inherently safer, despite what Jaws and Baywatch would have you believe, than almost any form of land exercise, says Gokul Kamath, coach of the national swimming team in 2006-07. Kamath, currently head coach at the Navi Mumbai Sports Association, says: “Unlike running and other types of impact exercise, swimming is impact-free and can be practised by people of all ages. It also works out your entire body.”
Also, according to Santosh Jacob, a doctor of sports medicine and founder of the Indian Academy of Sports Research, Chennai, swimming is one of the few exercises “that incorporates respiratory and cardiovascular effort (breathing and blood circulation) without stressing the joints”. So with a scorching summer around the corner, you have good reason to ditch the sweaty gym for a cool pool.
Swimming’s standout quality is that it is at once both kinder to, and more demanding of, your body than any land exercise. Water’s higher density relative to air means that your muscles are forced to work harder in a pool than they would on land. The effect is similar to resistance training, used to increase muscle strength, says Ashok Seth, chairman and chief cardiologist, Escorts Heart Institute and Research Centre, New Delhi, and himself a scuba diver certified by the Professional Association of Diving Instructors. “Also, unlike other forms of aerobic activity (such as running, tennis or aerobics classes), swimming requires you to use almost all your muscles at the same time, both upper and lower body,” he adds. All swimming techniques, except the backstroke, harness the deltoids (upper back/shoulder), abdomen, glutes (buttocks), hamstrings (back of thighs), quadriceps (front of thighs) and plantar (foot) muscles to varying degrees.
The higher density of water also counteracts gravity, reducing stress on joints and muscles. “All forms of activity or exercise put stress on our joints,” says Dr Jacob. “A joint with pre-existing arthritis will definitely be aggravated by running, as it is an impact exercise. But when swimming, you exercise at 30% of your body weight and, hence, cut out the risk of musculoskeletal stress, which may lead to the degeneration of joints and aggravation of muscle tears.”
Indeed, Dr Seth says, not only does water ensure there is no direct impact on joints, it also prevents the jerks that are part of even gentler aerobic exercises such as walking. “All movements in swimming are controlled, slowed down by the resistance of water, which means there is hardly any risk of injuring yourself,” he says.
This is significant for everyone, from pregnant women to someone recovering from injury—indeed, pretty much anyone with a reduced capacity for tolerating jarring, repetitive workouts.
Good for the heart
Swimming is particularly beneficial for pregnant women as it strengthens the abdominal muscles, of particular importance to carrying a baby. It also strengthens the back muscles, making it easier for mothers-to-be to support the extra weight during pregnancy. Other common issues associated with pregnancy—high blood pressure and joint stiffness—can be eased by swimming.
Swimming reduces blood pressure and lowers the resting heart rate, reducing risk of cardiovascular diseases. “Though there are no evidence-based studies on the effect of swimming on ischaemic heart disease (characterized by reduced blood supply to the heart muscle), a controlled workout involving 30 minutes of freestyle or breaststroke can definitely reduce the risk of a heart attack,” says Dr Jacob.
But what about people with existing heart conditions? For them, Dr Seth advises caution, “Patients with heart disease can drown if there is a problem while in the pool, so before swimming they need clearance from the doctor.”
For the rest of us, though, Dr Seth says, “It is perhaps the only form of exercise that provides aerobic benefits from raising your heart rate and increasing your lung capacity (because it needs breath control), as well as exercising muscles throughout your body.” Ruchira Tendolkar, technical director, BFY Sports and Fitness, Mumbai, notes that the benefits of a daily swim include stronger heart and lungs, better blood circulation, increased strength and endurance, and enhanced neuromuscular coordination. “These translate into a reduction in risk factors for lifestyle diseases (coronary artery disease, diabetes and so on), such as improvements in lipid profile, better control of blood glucose, reduction in blood pressure and a reduction in weight as well,” she adds.
Swimming also offers special benefits for seniors. “It increases a person’s capacity to use oxygen, which deteriorates with age,” says Dr Jacob. Dr Tendolkar adds that it helps maintain flexibility, which also tends to decline with advancing age.
While running—and to a lesser extent weight training—restrict your joints and muscles to a limited range of movements, swimming is more flexible. Depending on your level of fitness, you can adopt the demanding butterfly stroke, the milder freestyle or the fluid breaststroke.
Dr Jacob says: “The butterfly stroke is the most demanding of all and burns the most calories, while the backstroke and the breaststroke are less demanding. A combination of freestyle and butterfly is ideal for the experienced swimmer; a mix of freestyle and breaststroke is best for beginners.”
The breaststroke, Dr Jacob adds, is perfect for warm-ups, and has the lowest potential to pull or strain your muscles. Freestyle is somewhat more vigorous and requires more effort, while the butterfly stroke makes the highest demands on your muscles—especially your back and shoulders—and lungs. The backstroke is slightly different from the rest as it relies less on muscle power, activating mainly the muscles of the abdomen, groin and neck.
Experts are not unanimous in endorsing swimming as simply a good weight-loss tool. An hour at moderate intensity (raising your heart rate to 60-70% of its maximum capacity) in a 60kg man burns 540-650 calories.
“For significant weight loss, it would have to be sustained for a much longer time,” says Dr Seth. Or you would need to work harder, making it an intense workout (90% of maximum heart rate), which depends on your effort and fitness level rather than speed, Dr Jacob points out. That’s the difference between, say, a brisk walk in the park versus one that leaves you sweaty and breathless.
Recreational swimmers don’t usually make that effort, Kamath notes. To shed serious inches, therefore, they may be better off adding other cardiovascular (such as running, cycling or aerobics) and anaerobic exercises targeting specific muscle groups.
Dr Seth also notes two drawbacks to swimming. The first is that access to a pool, and a hygienic one at that, is not universal. Not only must it be well chlorinated, it must enforce rules of showering well to clean up before a dip. “Unfortunately, we Indians tend to regard swimming itself as a bath,” says Dr Seth.
The other caveat is weather. Unless it is a heated, enclosed pool, you have to wait for summer. Which, fortuitously, is right now.