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The mathematics of weight loss on a bike

There is really no mystery here. When riding a bike, one burns calories. The amount of calories one burns depends on one's weight. And if you burn off 7,000 more calories than you consume, you will lose a kilogram. Or so they say.

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For a person of my weight, riding a bike between 12-13.9 miles per hour, I should burn off 755 calories. Pedalling faster, between 14 to 15.9 miles per hour, I would burn off 944 calories. Those are the numbers from my Palm-based Diet and Exercise Assistant software. They make for pleasant reading and really encourage me to get on my bike.

But these numbers vary wildly depending on the source. For example, according to the Nutristrategy site, biking 10 - 12 mph making a "light effort" would burn off only 531 calories an hour for a person of my weight.

Faqs.org tells me that a 190 lb person pedalling 12 mph will burn off even less -- 472 calories per hour.

And according to Diet and Fitness Resources, a UK site, biking at 5 mph (perhaps a more realistic pace) would burn off only 240 calories in a hour (they don't say for what weight). This sounds like even less than what one burns walking, which might be the case if you are only gently gliding around on a flat surface and hardly pedalling at all.

Obviously there are other factors -- such as the difficulty of the ride (riding uphill will burn off more calories), water loss (perspiring a lot will lead to temporary weigh loss), and one's own fitness level.

And there are countervailing forces at play as well -- the more and harder one bikes, the more muscle mass gets built up in one's body. For this reason, many top athletes (and I think all players in America's National Football League) are technically considered to be obese, as their muscle weight gives them a body mass index in excess of 30.

Back to normal, middle-aged, overweight blokes like myself. Let's say I want to lose 16.6 kilos (which is a great deal, I know). That would require me to burn off 116,200 calories above my normal calorie expenditure. Biking half an hour a day at a 5 mph clip would expend 120 calories, so it would take 968 days to reach my goal. Knock off a day a week for resting, and basically we're talking about three years. Yikes.

The key here is not so much the intensity of the effort (biking half an hour a day at a moderate clip will not kill anyone) but persistence.

Comments

think it probably changes as you get fitter. i have ridden an 18 mile route three nights this week at an average 28kph and burned around 560 calories each trip according to my polar hrm.
but it was fun and the rest is just numbers