Energy expenditure on bike vs. run

Triathlon Forum
1

This is an offshoot of a recent, and rather lively, discussion on using watts on a bike to estimate energy expenidture (calories). I used the recommended calculator on www.analyticcycling.com and I got roughly 250kcal/hour. My ride was 3 hours on a practically flat road, using my roadbike, at an average speed of 26kph (which is subjectively my “aerobic” pace). My first question is–assuming I inputed the correct values, does 250kcal/hour while riding easy-moderate make sense? My Polar gave out almost 2500kcal for the whole ride! Second question–obviously I can’t measure wattage while running but can I extrapolate the 250kcal/hour as my running EE if I run at about the same perceived exertion?

I’ll be joining my first IM in April (IMOZ) and I’m really anxious to dial in my caloric consumption. Any input will be appreciated!

Kim

2

250 pr H is not enough (if you weight more than 30 kg). For a 150lb/67kg person the average kcal consumption on long distance racing is 5-800. But since a part of it (30-70%) is fat, you only have to consume approx 50% of it during the race. Go for at least 2 kcal pr lb body weight. You need to consume the most of it while riding, it’t not possible for most of us to consume enough while running.

3

If I remember from my physiology classes correctly you can factor in expending just about 100 kcal/mile while running.