When the porter Ranch YMCA introduced the new Life Cycle bikes, fully equipped with computer technology, we were all excited! The bike can track RPMS (revolutions per minute), WATTS (energy or power used), duration, mileage and how many calories a person is burning. If you wear a heart rate monitor, the bike synchs with it and shows you your heart rate. It also has a USB plug in case you want to record your workout.
One would think that the members would be super excited and most of them were. However, many were very disappointed when they realized that they weren’t burning 1000 calories an hour. Some of the members who struggled to lose weight was also enrolled on a computer online service that helped track her workouts. According to the service, one hour of indoor cycling burns 1000 calories an hour. They were devastated when the consol on her new bike told her she was only burning 250 calories an hour.
Then again, when I was trained on the bike, I was told that there was a good chance that the members were burning more calories than indicated on the consol. She said that the bike was designed so there was no way the members were burning “less” than the number on the machine. The numbers were based on the lowest estimate. This was an ethical decision on the part of Life Cycle. They didn’t want to falsely claim that you are burning 1000 calories so you can eat a ton of junk after your workout, then wonder why you aren’t losing weight.
Some people also found that they burned more calories on one machine than they did on the other, even though they felt like they sweat more and worked harder on the machine that they were burning less calories on. This is due to nothing but inaccuracy of the machines and how they estimated caloric burn. Some machines ask for your weight and others don’t. Without knowledge of your weight, or resting heart rate, the machines can only be so accurate. Many people found that what their heart rate monitors said didn’t always match what the bike said. In fact, the numbers could be more than 100 calories off depending on the day and which bike was used.
These leads me to one of the most common questions people ask me at the end of a class or session, “How many calories did I burn? (How much energy or fat did I burn?)”
This is a difficult question to answer because that magic number is based on many factors such as the current weight of the individual, their metabolism and their fitness level. There are many ways to record calories, from reading one’s pulse to using heart rate monitors or cardio machines such as the Life Cycle bike. All of these machines vary in accuracy and quality
If you are on any blood pressure medication or beta blockers, reading your pulse or using a heart rate monitor does not apply to you. If you are on blood pressure medication, do not bother using heart rate to measure caloric burn. Your medication changes how your heart beats and renders measuring your heart rate as a way to determine energy expenditure useless.
Then what is the best way to measure how many calories I am burning?
Most experts agree that the most accurate way to measure caloric expenditure is by using the Rate of perceived Exertion (RPE) method. This method is not based on a machine or heart rate but on how you feel. It is based on a scale of 1-10.
A RPE score of 4-6 moving but not struggling. 4-6 means that you are exercising comfortably, sweating and pushing but not to the point of great suffering. You can still talk.
A RPE score of 6-8 means that you are breathing hard. You are working so hard that you can’t talk. You might manage a curse word at your personal trainer but that’s all the talking you can do. You can still continue for over a few minutes but you’ll probably be completely exhausted at the end.
A RPE score of 8-10 means that you are pushing so hard that you can barely keep up. You will have to stop after a few seconds because your body won’t be able to take this type of exertion for very long. I often tell my students that the more you suffer the more calories you are burning and this is the truth. I’ll go into more details on this later.
You may ask, “With all the latest technology, isn’t there an accurate, measurable way to calculate caloric expenditure besides using the RPE method?”
Yes, there is. The most accurate way to measure caloric expenditure is to hook you up to monitors that track your heart rate, repository signals and metabolic reactions. This can be done in a laboratory.
There are two mathematical formulas used to track heart rate and caloric burn. The easiest way to determine your maximum heart rate (the fastest your heart can pump in one minute when exercising hard) is to take the magic number 220 and subtract it by your age. However, in a laboratory setting, this method has proven to be as much as 20 heart beats off! This is probably due to the fact that it only uses age as a method for determining metabolism.
The other, more accurate formula is to take the result of subtracting your age from 220. Then take you resting heart rate (the amount of beats your heart can beat in a minute while in complete rest. This is best measured when you first wakeup in the morning) and subtract it from that number. Now determine how many calories you want to burn. If you want to burn a ton of calories, estimate 50 to 80% of your max heart rate, divide that remaining number by 50% or 80%. This will show how many beats per minute you need your heart to beat in order to be working out at this intensity. This formula (the Karvonen) formula is more accurate but still can be up to 10 beats off measurements done in a laboratory.
Websites such as this one can calculate this for you:
Again, these methods should not be used if you are on blood pressure medication and the RPE method is much more accurate.
Okay, back to the magic question, “how many calories did I just burn?”
I will divide workouts into four catagories:
Fidgeting – 50- 150 calories per hour. RPE of 1-4. Heart rate is at rest to up to 40% of max heart rate.
Light aerobics—150-350 calories per hour. RPE of 4-6. Heart rate is 30-55% of max heart rate.
VO2 max—350-600 calories per hour. RPE of 6-8. Heart rate is 55-70% of max heart rate.
Anaerobic – 600-1000 calories per hour. RPE of 8-10. Heart rate is 70-90% of max heart rate.
How to understand the differences:
How do I know if I’m fidgeting? Studies have shown that people who fidget burn up to 150 calories more a day than people who don’t fidget and move around. This is the same amount of calories an average person burns by using a cardio machine for a half hour. So everyday tasks burn calories. Examples are: Climbing stairs, walking a dog, taking a stroll, housework, twitching or any other restless movements.
How do I know if I’m doing light aerobics? You are hot and sweaty but you can still talk. You are exerting yourself but not to the point of having to stop. The average fitness enthusiast works out at this pace. Examples of light aerobics are: Walking or light jogging, dancing, light cycling, circuit training with lighter weights or movements that aren’t extremely difficult, any movement that is at a pace that you can keep for a long time without having to stop and take a break.
How do I know if I’m doing my VO2 Max? You are struggling and breathing hard but you can keep going. You might be able to say a quick phrase or word but you can’t continue talking. This is a more advanced workout. Examples of VO2 max are: Running a long distance race as hard as you can without stopping, high impact aerobics, hitting or kicking a bag as hard as you can for a long time, cycling up a hill, kettle bell workouts, a hard circuit with difficult moves and heavier weights.
How do I know if I am doing anaerobic training? You are pushing to failure. You are expending yourself to such a high intensity that you have to stop, take a timed break or a few breaths of rest. It is not anaerobic if you are not pushing to failure. You rest between bursts of energy because you have to. This workout is for elite athletes or people who are very fit and not prone to injury or heart attack. Examples of anaerobic training are: Interval training, high intensity boot camp, tabata workouts, speed intervals such as sprinting for a timed interval with timed rest intervals in between, plyometrics (explosive power moves), heavy weight lifting that incorporates many muscles (including the legs) such as Olympic lifting with timed rest periods.
Keep in mind that if you are not fit, you don’t have to do much to burn a lot of calories. For example, I always teach mixed levels and give options in my bootcamp classes. Sometimes I will see someone who is advanced and can do the harder moves without suffering too much. Next to that person will be someone else who is new or not as fit. That person will be doing beginner moves but they are huffing and puffing and I can tell they are really exerting themselves. So, I can safely say that the latter person, the one who is huffing and puffing is burning more calories. This is why RPE is so important. After the latter person loses twenty pounds it will become easy to do the beginning moves because he/she no longer has to carry so much weight. They aren’t huffing and puffing as much so they probably aren’t burning the same amount of calories they used too. This is when it is time to move on to harder moves if one wants to continue losing weight.
For more information on plateauing and how to break a plateau, check out this link:
For more information on plateauing and how to break a plateau, check out this link:
For more information, also check out this link on eating, burning calories and how to get bigger or smaller: