Does Burning Calories and Fitness Have Anything to Do With O

cieraangel

Steady-state cardio activities have relatively fixed energy costs. You will burn fewer calories by losing weight, but not by becoming more fit.

I always use the example of running 6.0 mph (10:00 mile) because it makes the arithmetic more simple. At this pace, you burn roughly 10 calories per kilogram of body wt per hour. Someone who weighs 90 kg (little under 200lb) will burn 900 cal/hour at this pace. If they loose 20 kg (now at 70kg) they will burn 700 cal/hour.

However if they stay at the same weight, but improve fitness level, they will still burn 900 cal/hour. Heart rate may decrease because maximum fitness level has increased, so the workload is now a smaller percentage of maximum. However, calories burned does not decrease.

Let's say our 90kg person has a VO2 max of 12 METs. Running at 6mph represents 80+% of maximum, so it will feel like hard work. Let's say the person increases VO2 max to 14 METs, but doesn't lose any weight. NOW, that speed of 6.0 mph represents 70% of maximum (10/14). It will feel easier, and HR will decline, but the person will still burn 900 cal/hour. That's because the energy cost of running 6.0 mph is relatively fixed--it's the same more or less no matter who is doing it.

This is what I was thinking, but I've heard people say that they've stopped losing weight because their body got used to a type of workout so they had to switch it up. That made me a bit confused there. I do weigh less, and I am taking that into account with calories burned, but I was just making sure that being "used to" an exercise does not affect calories burned.