For the past three years February brought a record number of people to the Patti and Allan Herbert Wellness Center. It was the only month of the year that the turnstiles at the gym’s entrance clicked more than 80,000 times.
“February is a good time for people to start working out if they did not already start in January,” said Ashley Falcon, the assistant director for Wellness. “They no longer have that impending turkey dinner to get in the way.”
However, for the past three years the turnstile counts dropped in March and April.
“There are many reasons why people quit working out,” Falcon said. “Including not seeing results.”
Expectations for these results are often not met as people overestimate the amount of calories they burn because they believe the calorie count on the aerobic machine.
“I hear it all the time, people talking about how they burned 750 calories an hour,” said Tony Musto, the associate director for Fitness. “But I know that is not the case.”
In an attempt to learn the actual amount of calories burned while working on an aerobic machine, Musto, who has a Ph.D. in exercise physiology, and I used a metabolic cart to calculate the exact amount of calories burned.
This metabolic cart is more accurate than the machine as it measures the amount of oxygen a person uses, which can be used to calculate energy expenditure and therefore the calories burned.
The calorie counts on the aerobic machines predict the amount of calories burned by the weight the user enters. This equation can be inaccurate as two individuals with the same body weight can have different body compositions and fitness levels. Since fat is not as metabolically active as muscle, the person with greater muscle burns more calories than an individual of the same weight with a fatter body composition.
With Musto’s assistance, I measured my caloric expenditure on the elliptical, StairMaster, treadmill, and upright bike. On each we raised my heart rate to 150 bpm.
However, we also tested the calorie counts of machine when done in an incorrect manner; on these tests my heart rate deviated from this standard.
Also noted was my perceived rate of exertion, RPE, to see how hard I thought I was working. RPE is a self-assessed number chosen on a scale from 6 to 20, where 6 is very, very easy and 20 is very, very hard. These scales are placed on the pillars in front of the aerobic machines in the Wellness Center.
Elliptical
The elliptical, when put on a high elevation and resistance, burned the most calories of all four machines according to the metabolic mouthpiece. The elliptical calorie count was very accurate on this test.
However, on another test we put this machine on a low elevation and resistance. Here, the elliptical said the same amounts of calories were being burnt as the previous test, but the metabolic mouthpiece showed that I was burning two fewer calories a minute. My heart rate was 136 bpm. If the machine is used in this manner, it is the least effective aerobics machine of the four I tested in terms of burning calories.
To get the results of the first elliptical test, the elevation and resistance should be set so that an individual’s RPE is at a 15. On the second-elliptical test my RPE was eight.
When I cheated by leaning on the handrails of the elliptical my calories count was five calories fewer per minute than the amount the elliptical showed and my heart rate was at 140 bpm.
StairMaster
The StairMaster’s prediction on the amount of calories burned was a little less than the amount the metabolic mouthpiece showed.
However, when I cheated by leaning on the machine and wrapping my arms around the screen, the metabolic mouthpiece showed that my calorie count dropped by five calories a minute and my heart rate went down to 128 bpm from the 150 bpm standard.
When I cheated, the StairMaster still had the same calorie count as it did when I was doing the machine correctly.
Treadmill
The metabolic mouthpiece showed that the treadmill’s calorie count over-predicted by three calories a minute. In reality, the treadmill burns a similar amount of calories as the StairMaster.
The treadmill was put on a speed and incline that made my RPE a 16.
Upright Bike
The upright bike, although similar to other machines in calories burned, required the most effort to increase my heart rate to 150 bpm (my RPE was 16-17). According to Musto, this exertion is necessary because my weight was supported by the bicycle seat. Therefore, while on a bike the user can use fewer leg muscles against the pedals’ resistance, causing fatigue.
The calorie count on the bike over predicted the calories burned by around one calorie a minute
Recommendations
The American College of Sports Medicine recommends doing an aerobic exercise three to five times a week. Each session should be 20 to 60 minutes long and elevate an individual’s heart rate 60 to 90 percent of their heart rate max.
Also, according to Musto, it is very important not to cheat on these machines by leaning on them.
“If it is too difficult to maintain the workload without cheating, it is better to reduce the workload on the machine and do it correctly,” Musto said in an e-mail. “As your fitness level improves, you can slowly increase the workload on the machine.”
These measurements will change with an individual’s efficiency and body composition.