Watts to calories calc

markwb79

Saw it recently, but cant remember where.

If I average 200watts for an hour, how do I work out how many calories are burnt?

amaferanga

200W = 200Joules per seconds.

You want to work out energy in kJ expended in an hour. So 200 x 60 x 60 = 720,000 Joules = 720kJ.

This figure (720) is the approximate calories assuming 25% efficiency. Efficiency is probably a bit less than 25% meaning the calorie figure should be a little higher, but assuming it is makes the calculation easier and should give a lower bound for the calories you burn.

markwb79

Thanks a lot, not too far off what my Garmin said actually. (granted I have assumed the watts part)

danowat

Markwb79 wrote:

Thanks a lot, not too far off what my Garmin said actually. (granted I have assumed the watts part)

LOL

markwb79

whats funny about that?

okgo

You can't assume the most important figure!

t.m.h.n.e.t

Markwb79 wrote:

whats funny about that?

Something about relating HR or GPS based calories to power output.

Herbsman

Markwb79 wrote:

whats funny about that?

What isn't funny about it?