Is your favorite machine telling you the correct calorie burn?
By Judy Torel
“I worked out on the elliptical trainer yesterday and burned 1,400 calories in one hour” reported one of my clients.
Another female client who is 5’1”, 110 lbs. and is an avid runner said: “I burned 500 calories for my 30-minute jog on the treadmill.”
Most gym and home-use cardio workout machines will give you a total calorie burn at the completion of your workout. Can these numbers actually be correct or is 1,400 calories for one hour an over-estimation that can mislead a person to think they can eat more food when they are trying to lose weight?
How do the machines determine calorie burn?
The computer on a cardio machine has been programmed with standardized equations that estimate calorie burn for the type of activity performed on the machine. These equations have been developed from actual measurements taken by exercise researchers on subjects who have been hooked up to special lab equipment while exercising on a various machines. Hundreds and thousands of measurements have been taken and then equations were designed based on these measurements. So for instance, hundreds of measurements were taken of males of a variety of body weights while they walked on a treadmill at 4.0 miles per hour while not holding onto the hand rails. This information is transposed into a calorie burn equation and then put into the computer on a treadmill. The same has been done for bikes, rowing machines, arc trainers and ellipticals, among others.
What can cause the machines to over-estimate your calorie burn?
There are many factors that must be taken into consideration in order to determine an accurate calorie burn on a piece of cardiovascular equipment: Weight, height, age and gender. If you have not programmed your personal data into the computer on a piece of cardio equipment, then the calorie burn total displayed will not be accurate.
Most machines have a quick start button that will use a default weight and age already pre-programmed into the machine. Each type of machine has different default settings because there has yet to be a standardization of this in the fitness industry. And, many machine companies will use a large default setting, like a 180 pound, 5’8”, 25-year-old male so that the calorie burn will appear to be large. This will make the user feel like they get the better workout on this machine and therefore will want to use it more.
If you do plug in your personal data, you will get a more accurate measurement than if you use the standard default setting, however even plugging in your data does not guarantee accurate calorie readings.
Level of fitness. If you are a seasoned runner then you are going to burn less calories at the same speed of a less fit person who is the same age, gender, height and weight. The more fit you are in a particular activity, the more efficient you become at that activity, therefore the less calories you burn. So, two people running on a treadmill who are alike in all personal data except fitness level will not burn the same amount of calories. Unfortunately, the computers on the machines cannot determine fitness level and therefore will assign the same number of calories to each individual once their personal data has been entered.
How you use the equipment. If you hold the handrails while walking or running on a treadmill, you are displacing your weight onto the machine, therefore reducing the amount of calories required to move your body weight on the machine. If you plugged in your body weight, but 10 pounds of your weight is supported on the handrails, then the calorie reading will be higher than what you actually burn because the equation in the computer assumes no handrail-holding.
If you lean on the handles on the elliptical machine, you are displacing up to half your body weight, resulting in a calorie reading that is significantly higher than what you are actually burning!
If you vigorously swing your arms while you walk on a treadmill, you may get a calorie reading that is too low because the program in the computer assumes normal movement of the arms while walking.
History of the equipment in the fitness industry. Treadmills are more accurate in their calorie readings than the elliptical machines because they have been around much longer and the equations used to estimate calorie burn at specific speeds and inclines have been tested on many more subjects than the newer elliptical or arc trainer machines.
According to John Porcari, PhD, a cardio-machine researcher and professor in the Department of Exercise and Sport science at the University of Wisconsin in La Crosse, because there are many more variables that the machines take into consideration, these machines can be anywhere from right on the money to 50 percent off.
So how do you know if the calorie reading is accurate for you? What I tell my clients is to do a 10 minute warm up on a treadmill. Then restart the machine, plug in your personal data and either walk or run at a speed that is a challenging, but maintainable effort for one mile (without using handrails). Check how many minutes it took and look at the calorie readout. Use this calorie burn for all other machines when working out at a similar effort. For instance, if your readout on the treadmill test says you burned 125 calories for one mile and it took you 16 minutes to walk it, then when you are on the elliptical, make sure you are on a setting that feels like the same effort as the treadmill test and for every 16 minutes use the 125 calorie as your burn.
Just don’t be surprised when you discover that what the machine tells you that you are burning is significantly higher than what you get when you use my equation!
Judy Torel is a therapist/personal trainer with a Master’s degree in psychology. She is certified through the American College of Sports Medicine as a fitness trainer and works out of Planet Fitness and Deb's Sweat Shop Extension. She can be reached at JTOREL2263@yahoo.com