How many calories can I burn in a session?

We get this question A LOT!!

As one of my trainers put it.. “I know this is a difficult one to answer due to the different facts for each individual but can I give a rough number”

Here is what I said and would say to any trainer or client looking for that magic number which is given out without any concern for the truth..

Yes you can.. you can make one up! That is what all the other bootcamps do and then claim it has been tested (don’t you just love this industry :))

Seriously, how long is a piece of string. Here is my reason why..

No two members will be the same.. depends largely on current fitness level (as fitness increases calories burned both during and after also increase).

Due to the high EPOC (excess post-exercise oxygen consumption) training effect, more calories are burned after the activity in addition to during the exercise making it even more difficult to determine nett EE (energy expenditure) effect of the workout.

Where you see in others advertising.. this bootcamp burns X per session is garbage.. as this is not an absolute number and where one person could burn 5 Kcals per minute during and another 15 kcals per minute both are taking part in the same workout!

Imagine 2 people running on a treadmill and for this purpose they both have identical body comp.. one is running fast and the other is running slow yet they are both working at the same relative intensity its just that one cannot run as fast as the other. But both are using the same equipment (a treadmill)..

The bootcamp is like the treadmill and the intensity of the runners on the treadmill is like the ability of 2 different members intensity during the session. Lets say the fast runners energy expenditure (EE) is 2-3x more than the slow runners EE.. so to say the treadmill will burn a set amount of calories would be grossly incorrect!

Also amount of LBM determines individual energy demand as well as bodyweight (carrying a larger frame will increase energy demand however usually larger frames cannot maintain adequate intensity long enough to equal greater overall burn rate of a slimmer fitter individual).

The fitness test can determine individual estimated VO2 max. From there we can estimate an individuals Kcal/min during the workout.

However, depending on the ability to maintain high anaerobic threshold intensities during the session, will determine the level of EPOC .. which may account for a large post workout EE.

Impossible to guess!!

Here’s an article I originally wrote 10 years ago explaining some of the variables..
https://joinjj.com/fat-burning-zone-not-the-way-to-lose-fat/
Gives you some numbers to work with.

Basically KCals are calculated at an absolute rate of 5 Kcals per liter O2 consumed. Relative Kcals/min calculation is based on (Vo2*bwt(kgs))/200 .. note Vo2 (ml.kg.min intensity) is a major variable!

The Energy Expenditure audio interview in our trainer resources also discusses the variables when trying to predict EE from exercise.

How I (and most Exercise Physiologists) suggest you go about determining relative intensity / EE would be to use a field test (although this only measures the workout part). Here are the steps:

1. Test Est. Vo2 Max via fitness test

2. Estimate HRmax or directly measure it during test

3. Put a HR monitor on the subject during a session and gather mean HR (intensity) related to RPE (rate of perceived exertion)

4. Compute exercise metabolic profile to provide subjects HR and kcal correlations

5. Multiply the Kcal/min at the mean intensity (HR) by the number of minutes of the session.

Or simply guess 😉

.. seriously I would not be happy guessing!!

So although I could and do use metabolic equations related to a clients Vo2 Max) this does not allow for the EPOC.

Your best answer is..

It is possible to estimate with some degree of accuracy a persons individual kcals per session by conducting a series of tests (we do this).

However, it is impossible to estimate a sessions output for a group. And anyone who says they can do this, is speaking from a gimmick or serious lack of knowledge and not a scientific fact. Per person yes, from a group NO.

 

If you are a trainer reading this, you can find out more about Exercise Physiology and Metabolic Equations here [ https://metabolictrainingeducation.com ].

Metabolic Calculations is part of what we teach to ACSM Candidates, Personal Trainers and Allied Health Pro’s in our Metabolic Expert Series.