Q Is it true that a person will use the same amount of calories over a given distance regardless of how fast or slow they run? My theory is that two runners with an identical metabolic rate would use the same number of calories over a set course.
The rate at which our bodies burn calories is determined by many factors, of which time and distance are only two.
First the science bit: our basal metabolic requirement (BMR), the number of calories we require over 24 hours, is dependent on age, sex, height and weight. A 64kg man, for instance, has a BMR of about 1550 calories, while a 64kg womans BMR is around 1400 calories.
As you lose weight, your BMR drops. This effectively means that you have to exercise harder and longer to burn the same number of calories. Lots of studies have confirmed this. Most recently, for example, researchers at Dunn Nutrition Laboratories in Cambridge found that overweight people burned more calories in a step test than the leaner participants.
So what about your theory? Well, youre right. Even if one of your identical runners ran five miles in 30 minutes, and the other jogged the same distance in 45 minutes, there would be a negligible difference in the calories burned. In fact, this would hold true even if one walked the distance.
The difference comes once the two runners have stopped. Several studies show that there is more likely to be a prolonged rise in metabolic rate (around five per cent higher than normal) for up to eight hours after intense exercise than after moderate physical activity. This means that the faster runner in your scenario stands more chance than the slow jogger of burning some extra calories after he has finished.
Peta Bee, RW Nutrition Editor
I am a 40 year old, 5'10" man, and I used running as part of a weight loss plan. When I ran my first 10k race I weighed about 13.5 stone, and finished in a little under 44 minutes. Just over a year later, with my weight down to 10.5 stone, my 10k time was down to just under 35 minutes. Now, weight loss on its own didn't account for all of the improvement - I was training pretty seriously as well - but it certainly helped. The other point to bear in mind is that weight loss improves your ability to train hard and consistently, since it reduces the impact on joints, and therefore the risk of injury. The optimum running weight for me, by the way, is about 2lbs for every inch of height, plus 10 lbs. This calculation gives a BMI towards the bottom end of the healthy range of 20 - 25. Cheers Daniel
Posted: 07/10/2002 at 12:22
I agree with Tim Weatherhead about running to enjoy it and feel fit. I started following a training programme to improve endurance and fitness. A side effect is that I've lost a bit of weight, but not as much as I would have if I was following a diet and exercise programme with the specific aim of losing weight. Yes, I'm watching what I'm eating but in the sense of eating for maximum fuel for my run, rather than "ooh, I can't have that cos it's fattening". But! Because my goal is different to simply losing weight, I'm not disappointed by the meagre loss (about 7 lbs or so in the last 2-3 months). Instead, I'm chuffed that I can run and enjoy it without feeling like an overstuffed sack of tatties. And, would you believe it, someone said to me yesterday that I look like I'm much thinner and have lost a lot of weight. Definition, definition, definition!
(Hmmm... methinks my wee rant is off the subject of the original question!)
Posted: 24/04/2003 at 10:19