Thursday, January 26, 2012

Calories and just how many am I actually burning?

This isn't about calories consumed, as there are a million sites out there that help with that, one fun one is Get Drunk, Not Fat, about getting the most alcohol per calorie, and there are a plethora of sensible ones, this is about how many calories are getting used up during exercise. The whole calorie thing isn't as exact a science as you might hope and many discussions go on, daily, on the many exercise forums on the Internet. I've found a couple of good resources about calculating calories burned and the associated VO2 max values needed in order to find out. In case you don't feel like clicking on the link VO2 max can be defined as the maximum capacity of an individual's body to transport and use oxygen during exercise.

My good friend, Endomondo, seems to base it's calorie calculations on either your weight, the type of exercise and distance (for distance based exercise), or on weight, type of exercise & duration, this seems fairly close in some occasions but not in others. There always seems to be a lively debate about whether or not the site is calculating it's cycling calories burned as too high, funnily enough the runners seem to say yes, but the cyclists disagree, who'd have thought it?

The reason I started thinking more about this was that my regular lunchtime walk involves walking around this inside of the Ford offices, I work at, regularly interspersed with runs up to the 7th or 8th floor of the Ford World Headquarters building. This gets me (a) sweating & (b) feeling quite put out by having to choose 'walking' as my exercise type in Endomondo. I'm certainly not walking all the time, I'm not stair stepping either, as I'm taking these stairs two at a time, but I'm not running either. I have said previously that I have a nice Garmin exercise watch that monitors my heart rate, so I'd thought I'd see what could be done with that information, hence this posting.

To start, lets look at a couple of workouts;

Endomondo Calorie Estimates
Date Duration Av. HR Max. HR # Fights Calories
1/12/2011 1hr 1min 117 171 36 448
2/12/2011 1hr 2min 119 172 38 448

Both almost identical in duration, one with two more flights of stairs, but I can assure you that the second one was way tougher than the first. Ok, so now for a little analysis...

Equipment needed to find VO2max - and ergospirometry lab, funnily enough  I don't have one and don't plan on picking one up any time soon...

I found a cool blog about someone originally training for a triathlon, but now just keeping on exercising called Triathlon Training Blog, there is a page dedicated to trying to calculate calories burned based on average HR, see here. The problem with this site is that it requires that I estimate my VO2 max value, which led me to another couple of pages, Wikipedia &, that will help me try and calculate. Let's use some of the methods mentioned on these pages to try and get a very rough feel for what my VO2 max value actually is, so I can see if I'm getting ripped off by Endomondo and my stair walking.

VO2 Max Calculations
Method VO2 max
Resting Heart Rate Based 41 20sec HR value of 21
1 Mile Walk Test 42 15:30 for 1 mile
pulse of 105 on completion
1.5 Mile Run/ Walk Test 44 12:00 for 1.5 miles
Pedersen estimation
44.3 HRmax=192; HRrest=65
Cooper test 43.8 2,478m in 12mins
Average 43

So we can see that based on four different calculations my VO2max comes it at around 43, so now I can go back to the calories burned to see what numbers come out of that, I'll just add a column onto the table created earlier, as it's easier.

Calorie Burn Comparison
Date Duration Av. HR Max. HR Calories Calculated
1/12/2011 1hr 1min 117 171 448 624 +176 (39%)
2/12/2011 1hr 2min 119 172 448 653 +205 (47%)

Hey, guess what, I'm working even harder than I thought. I'm now in the process of creating a Google spreadsheet so I can do some more testing.

Note: In Endomondo's defense I really have no idea how far I am walking while inside the building due to GPS reception issues, but based on how fast I generally walk and how long I am out there I pick a nice round number and go for it.


  1. This requires too much thought for me. Does it make the time go by faster?

  2. Walking around the inside of a building, albeit a big one, is so mind numbingly boring that the mind does wander a bit and before you know it, 'time to hit the damn stairs again', so I'll go for 'yup'.