So it’s nearly Christmas! And most of us choose to forget all about our calories at this time of year . . . but give us a few more days, once we hit January 1st we’ll all be back at the gym trying to burn off our Christmas calories!  The receptionist at my gym in Northampton even noticed and commented on the fact that she saw me more in January last month than at any time of the year! (Oops!)

But the one thing I’ve always wondered after my work outs is whether or not those gym machines really can tell how many calories you’ve burned or if they are in fact just making it up.

One day I asked my super fit gym man and he said that the readings on the machines are only estimates, but they give a pretty good idea of what you’ve burned, so long as you’re honest with your information.  At the time I struggled to stop staring at his rippling pectorals without drooling, so I just kind of nodded, smiled and batted my eyelids.  But later on at home, after I’d managed to put my tongue back in my head I started to wonder what that really meant?

So I did a little research of my own, and I found that according to the experts there’s a good chance your calorie reading is not entirely accurate.

Is Your Gym Equipment Lying To You

Burning Calories: Number Crunching

When you’ve finished your workout, the majority of cardio machines will give you the number of calories that you have burned.  But you definitely shouldn’t take it as gospel.  It is only an estimate – and very often it’s an overestimate.

Pete McCall is an exercise physiologist and he says that there is usually a 10 percent margin of error on whatever reading your exercise equipment gives you.

“The number you see on the treadmill, stationary bike, elliptical machine, stair climber, etc., is just an estimate, but it is a relatively accurate estimate. It is based on what is called metabolic equivalents, or METs, which refers to how much oxygen your body uses.”

One MET is the equivalent of 3.5 millilitres of oxygen per kilogram of your body weight per minute, according to McCall. This is the quantity of oxygen your body needs when resting.  The harder your work when exercising, the more METs your body will burn.

“Your body has to expend energy to use oxygen. If you’re running, your body needs more oxygen and your body spends more energy,” says McCall.

At the gym, the cardio equipment uses data on the amount of METs it takes to perform the particular exercise. It will also use your weight if you choose to enter it (which I suppose is what super fit gym man meant when he mentioned being honest with your information!).  It uses this information to generate an estimate of how many calories you have burned doing said exercise.  McCall says it is more accurate if you enter your weight and your age than if you don’t.

If you are attempting to lose weight, you might be particularly interested in finding out the exact number of calories you have burned during a workout.

“If people are really concerned about monitoring weight loss, the gym equipment is a good estimate, but the best estimates are going to come from heart rate monitors,” McCall says.

More modern heart rate monitors let you program in your resting heart rate and your age, then they use the information to provide you with a more precise estimate of the calories you’ve burned.

Burning Calories: Maximizing the Burn

When choosing which piece of gym equipment to use to give you the best burn, don’t rely on the calories-burned estimates from the machines. The only way to burn more calories, is to work harder. So the best way to decide which piece of equipment will help you burn the maximum amount of calories is to gauge how hard you’re able to work on it — if you personally can’t sustain a workout on the elliptical machine, for example, use the treadmill instead.  It’s about finding out through experience what works best for you.

You can use calorie counters on gym equipment as a rough guideline, but the most important way to maximize the burn is to find a piece of equipment you enjoy using and to use it as often as you can.