Over exercising can slow down metabolism????

RayRay1500

I just saw someone write this in the forum to explain why someone may not be losing weight. I have never heard of this, has anyone else?

BrianSharpe

Could you link to the actual thread?

I'm not sure what theory was being presented but it could be possible that someone who did nothing but cardio and was eating at a significant caloric deficit (and a low % of calories from protein) could have their BMR lowered by virtue of the fact that they'd be losing lean muscle mass in addition to fat as part of their overall weight loss but to explain why they're not losing weight.......sounds a bit dodgy to me.

In the absence of a metabolic disorder eating at a caloric deficit will induce weight loss, maybe they were overestimating their calorie burn and eating back calories they hadn't really earned.

RayRay1500

I figured it sounded strange. Soooo many people give advice on here and have no idea what they are talking about!!

myfitnessnmhoy

There are three reasons that I can think of that this may be happening.

As mentioned by Brian above, if you're losing significant amounts of lean muscle mass as part of your weight loss, it is possible that you might be lowering your metabolism because lean muscle mass uses calories just existing.

Also, if your primary workout is cardio, there is a diminishing returns in cardio at a specific performance level as your cardiovascular capacity (stamina) improves. The answer, if you choose to stick with cardio, is to maintain the same heart rate, which means cardio should always get you equally out of breath. If you've been concentrating on maintaining a consistent 5k time and you're finding it easier, you are burning fewer calories doing it. Do a 10k instead. Up the game. Always up the game.

It could also mean that you're just simply overdoing it and can't maintain the same performance level. I have this happen all the time. When I do a full week of bike commuting (28-mile round trip), my speed and performance on Friday is a good chunk under what my performance was on Monday. The hills seem steeper, and I tend to attack them less aggressively because I'm sore and I'm tired. So I know I'm not burning as many calories as I do earlier in the week.