Physical Activity Energy Expenditure. What?

A few posts back, I began a series on nutrition and specifically energy expenditure. Today will continue that thought process in sharing what I am learning about physical activity energy expenditure (read about it here). More importantly, how this relates to resting energy expenditure. Let’s dig in.

More To Energy Expenditure Than Pasta

As an athlete (I use that term loosely at this point), I focus more and more on the fuel used to bring the best results to my training. Gone are the days of, “just eat more pasta!” Each training day requires a different amount of energy, and therefore, a different amount of fuel. Some days are much more strenuous than others depending on the training plan. This is where physical activity energy expenditure comes into play.

With so many variables, determining the actual amount of energy expended is more of an estimate than exact. The easiest way to estimate this amount is to multiply your resting energy expenditure (REE) by a physical activity factor. Finding these factors is both easy and difficult. If you Google it, then you’ll get almost 700 million results. In the chart below, I have compiled some that I think work well based on a number of compared sources.

ActivityActivity Factor
Very Light: Seated and standing activities,
driving, playing cards.
Light: Walking, carpentry, sailing, playing
ping-pong or pool, golf.
Moderate: Carrying a load, jogging, light
swimming, biking, calisthenics, scuba diving.
Heavy: Walking with a load uphill, rowing,
digging, climbing, soccer, basketball, running,
obstacle course.
Exceptional: Running/swimming races,
cycling uphill, carrying very heavy loads,
hard rowing.

Calculating Total Energy Needs

My REE figured in the previous post on the subject came to 1,622.60 kcal/day. If I know I’m doing a serious workout, then I’ll probably go for the factor of 2.1. If I know that I’ve got a longer running workout, then I’ll go the full 2.4. If it’s a rest day, then the factor would be 1.3 and would look like the equation below:

Total Energy Needs = 1,622.60 x 1.3 = 2,109 kcal/day

As mentioned before, this is an estimate. I find it useful to figure out each of the factors for each general activity (Very Light, Light, etc.). Then, I’ll keep track of my intake for a week or two in a very rigid manner (I go old school with a Leuchtturm1917 notebook). I’ll track every crumb. This helps me refine how I guage the caloric content of my intake.

I’ll also try to estimate the count compared to the actual. Usually, I convince myself that I am eating less calories than I actually am. On hard training days this isn’t much of an issue. However, on light days this become problematic. Though I never put much emphasis on weight, it does seem to be the best way to accurately monitor your energy balance of intake vs. expenditure.

Stay Flexible

For some it may be easy to get caught up in reaching the ideal number. This caution is for those people. Doing this rigidly for a week or two every few months should help refine portion size and control. There is also a difference in the quality of food (I’ll hit this later). So bottom line, don’t get too stuck on the numbers. There is no such thing as perfection.

Featured Photo by Fidel Fernando on Unsplash


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