Calories per Hour burned in Swimming: 300 (Picasso at 91) to 500 (average) to 2000 (Michael Phelps in 76 degree water)
An hour swim can provide an excellent workout, especially if you vary your strokes to use your muscles in all the different ways you can use them while streamlining in the water. If you weigh 150 lbs, you burn about 500 calories during that time, swimming at a moderate rate of speed with good muscular form including a 6-beat flutter kick and proper bi-lateral breathing technique. A moderate rate of speed is swimming about a mile and a third in one hour. Increasing the intensity (speed and muscular force) of your swim as well as varying your strokes from freestyle crawl to backstroke, to breaststroke to side stroke result in expending more calories plus burning them from different fuel sources (cabs or fats). If your muscles weigh more, you require more energy for the same workout and you burn more calories per hour, about 630 calories if you weigh 200 lbs. If you weigh 115 pounds, you will have to swim farther and faster to burn 630 calories in an hour, about a mile and 2/3 (which is very fast). The reason that swimming is such an excellent cardiovascular workout is because you breathe deeply and regularly throughout the hour, and oxygen is what burns anything, calories included. With forceful, attentive swimming, which includes sprinting now and again, your hr will vary from 120bpm to 150bpm for the entire hour. Note: it is not safe push yourself to swim at high intensity in water that is above 84 degrees, but you probably will not be able to swim at high speeds anyway in water above 82 degrees. Your body is not stupid enough to let you force it into a heart attack. It will just slow you down to the intensity at which your body can disperse the heat. Contrary to popular opinion, you do not sweat much in water because water is always many degrees lower than your core body temperature of 98 to 99—except through your mouth, like a panting dog—and only if the water and air are too warm for the workout you are doing. Your sweat point while at rest in water is when the water is 98+ degrees. To exercise in water that warm is critically dangerous.
Calories per Hour burned in Vertical Aquatic Exercise: 200 (short levers, lots of floating and chatting) to 500 (full ROM with down and through force, travel, using all planes of motion and especially two at once, long levers) to 2000 ( trained athletes at maximal speed and force using perfect form and breathing technique in water 82 or under.
Like swimming, and hour of vertical aquatic exercise alone or in a class can provide a fabulous muscle strengthening, flexibility, stretching, conditioning, and fascia toning and cardio-vascular workout. Also like swimming (and every exercise), there are multiple variables that affect how many calories are burned, though in water all of these effects are magnified. You burn more calories standing still in chest deep water than you do on land. It is hard to stand still in the water, and off the bat you use 12% more energy than on land and all your balance muscles, just to stay upright (when you float, you use the same number of calories as when you lie in bed). Unlike swimming, a person with a high bmi (lots of built in buoyancy from fat) will burn a lot of calories trying to keep their feet on the pool floor and their body upright while countering the water’s buoyancy and still move with intention through the water. If they sit on a noodle and float or even bicycle, they won’t burn many calories until they build enough muscle in their legs and abs and buttocks (the gluteals are the “better butter burners”) to really move at a high rate of speed through the water, backwards and forwards. (People with a high ratio of body fat to lean muscle should not use buoyancy equipment until they get leaner.)
People who are fit and toned and trained in the water will burn 2 to 10 more calories per pound per minute that very deconditioned people, again like swimming, depending on their bmi (relation between fat and muscle mass), their size and weight, and their focus. (Yep, focus. If you focus, are mindful of muscle movements, you will burn many, many more calories than if you are not paying attention). In 84 degree water a 150 pound person who is fit and trained and focused can burn more than 500 calories in an hour. But in water, as opposed to land, a 110 pound person can burn that many as well. (The reasons for this are very complicated, but they have to do with hydrostatic pressure and the distribution of resistence along the entire lever and maximal number of torso muscles recruited into use.) A trained aquatic athlete doing vertical aquatic exercise, especially fully suspended as in water polo with no support equipment, can burn 2000 calories an hour. A suspended cross county ski using no equipment using full ROM of levers and varying arms from sagittal (front to back, body split in half) to frontal planes( lateral abduction/adduction of arms) in backward and forward laps for one hour will clock you at over 1000 calories.Muscles and fascia (which carry the chi/energy throughout the body) burn calories through their tensile strength, stretching and contracting continuously, in eccentric (lengthened muscle) and concentric (shortened muscle) contractions. (A biceps muscle that can work to lower a weight on land while stretching out to its full length of 5-8 inches and can also contract to work the muscle in its fully shortened, concentric position of 2 to 4 inches to lift that weight, is a very strong and toned muscle from its center right out into its thin insertions of fascia/connective tissue into bone.) Fascia wrap all muscles, bones, organs, veins—so your colon, bowel, stomach, pancreas, liver, heart are also getting a healthy massage by the contractions and extensions of fascia as you exercise, especially in the water—they respond by secreting hormones that make you thin and shutting down the source of those toxic ones that make you fat and keep you that way. You also burn more calories walking in water than you do on land, but again only if you walk with good form, posture, and breathing while pumping your feet full ROM heel ball toe and clear off the toe forward (toe ball heel backwards) to use all the fascia and muscles in your feet with arms going down and through the water in opposition to the legs. If you walk like a cave man (right side of body then left side of body, you are not doing yourself a bit of good, in fact, harm.) There are hundreds of ways to walk in the water, but in all of them, the walker must be intent on using and increasing the water’s resistance and her/his own power to resist the water’s buoyancy. Power in the water is down and through, against buoyancy. A high leg lift in the water is silly and often dangerous (as it takes the joint way beyond normal range of motion) unless the intention is to power it back and down and through the greater distance and to take it as far in the other direction as you have lifted it in the first direction. The leg will float up by itself, with no exertion on your part. Power on land is up, against gravity. So putting your foot down is not hard at all—in this way water workouts are exactly opposed to land workouts. This is why almost no land exercise will work in the water without huge modifications, and the reverse. Doing aquatic exercise always requires training—it takes about six weeks of training to get it. And like any exercise, more and more training forever. There is always a higher level. In water, you really do have to learn bio-mechanics, at least the basic principles of opposed muscle groups which is the great secret of balance and strength as well as the basics of hydro-mechanics. (Of course, you should do that with all land exercise as well—but we think we know how to work our bodies on land. And that illusion is why imbalances in muscle strength and flexibility are the number one cause of falls and accidents and injuries of all kinds and eventually put half the population on walkers and in wheelchairs.)
In summary, you will burn more and more calories and have a much greater post workout calorie burn as your body composition changes from fat to muscle with your increased duration and intensity of exercise and focused, disciplined effort. If you add a lot of pleasurable laughter while exercising, you’ll burn even more calories (you take in a lot of oxygen and do a lot of muscle contracting while laughing—though best not while swimming).
Dr. Lucia Cordell Getsi, Ph.D., Master Trainer and Rehabilitation Exercise Specialist, WaterART Fitness International, © 2012.