A new study of six popular stationary exercise machines Americans use to torture themselves into shape has reached a startling conclusion: The treadmill, a contraption synonymous with drudgery, burns more calories than a stair-climber, a cross-country skiing simulator, a rowing machine and two different cycling machines.
Conducted at the Medical College of Wisconsin in Milwaukee, the study of 13 healthy men and women is the first to compare energy burned by people using those machines under controlled laboratory conditions at set levels of exercise intensity.
For workouts that the researchers described as “somewhat hard,” people on the treadmill burned about 40% more calories per hour (705) than they did on the least-calorie-intensive machine, the stationary bicycle (498). In between were the stair-stepping (627) and rowing machines (606), the cross-country skiing simulator (595), and the Airdyne cycling machine (509), which has handles moved by one’s arms.
“The surprise was that the treadmill came out better than rowing . . . and the cross-country skiing simulator,” said Dr. Martin Hoffman, a physical medicine and rehabilitation specialist who directed the study. It appears in today’s Journal of the American Medical Assn.
The findings go against much health-club wisdom, which tends to hold that the more elaborate the exercise machine, the more energy it demands. “Wow,” said Anthony Alvarez, manager of Bally’s Total Fitness club in downtown Los Angeles, when told of the finding. He had figured that the stair-stepper would come out on top.
Generally, the treadmill’s supremacy in this study offers some encouragement to people who jog or stroll without benefit of any machine. “It’s fair to think that walking and running outdoors or on an indoor track is going to be a very good mode of exercise,” Hoffman said.
The subjects in the Wisconsin study were eight men, averaging 35 years old, and five women, averaging 27. In terms of their initial fitness levels, they ranged from the virtually inactive to amateur athletes. Twice a week for four weeks, the subjects worked out on each machine for 15 minutes, learning to use it properly at different exertion levels.
The subjects, in effect, taught themselves to exercise at three different intensity levels on all six machines: “fairly light,” “somewhat hard” and “hard.” Those levels corresponded to a standardized scale used by exercise physiologists, the so-called rating of perceived exertion. The “somewhat hard” level fell within the American College of Sports Medicine recommendation that healthy people work out at 60% to 90% of maximal heart rate to optimize cardiovascular fitness.
Once the subjects were habituated to the different exercises, the researchers tested them as they worked out, measuring the oxygen they consumed, which directly correlates with the calories they burned. Hoffman said that although the number of subjects was small, the fact that each was tested on all six machines strengthened the observations.
The researchers cannot entirely explain why treadmill workouts burned more energy than the other workouts at the three exercise intensities tested. One factor, Hoffman said, is that running involves many large muscles, from shoulder to toe, working through a wide range of motion. In contrast, rowing doesn’t much involve the large leg muscles, and a stationary bicycle does little from the waist up.
The researchers cautioned that the findings don’t necessarily apply to the elderly or to people who are woefully out of shape. And the study was not big enough, they added, to tell if women and men respond differently to the exercise demands.
Moreover, Hoffman cautioned that the calories burned on a given exercise machine depend on a number of variables, including one’s size and fitness. For instance, a large man working out at the “hard” level on the treadmill burned 1,272 calories an hour in the study. A small woman doing the same thing burned only 564.
In terms of calorie savings, though, even the seemingly small differences among the various machines can add up. A half-hour treadmill workout might burn just 40 more calories than a comparable workout on a stair-stepper. But that small edge, multiplied three times a week, could lead to several extra lost pounds over a year, Hoffman said. “It sounds small but it can really be important,” Hoffman said.
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A study comparing energy burned by people working out on six types of exercise machines found that the treadmill came out on top. The energy expenditures shown here are average values; individual values will differ depending on body size and fitness, among other things.
Calories per hour
Rowing machine: 606
Cross-country ski simulator: 595
Airdyne cycle: 509
Cycling machine: 498
Source: Journal of the American Medical Assn.