T Nation

Body's Water Usage - Cardio vs Resistance

I’m curious as to the bodies’ water loss during cardio vs. during resistance training. I know it doesn’t matter too much, and I drink plenty of water, but I was just wondering.

Logically it would stand to reason that moderate cardio would use more of your bodies’ water stores than even a high volume resistance training session due to sweat. But is this the case? What are the other causes of water loss besides through the sweat glands?

Basically, there are four ways that you can lose water. First, there is insensible water loss, which is roughly 28% of the total you lose everyday. This is water that vaporizes out of the lungs or diffuses through the skin. Also, there is obvious perspiration (8%, although this number will go up with exercise), and that lost in feces (4%) and urine (60%).

I’d have to say that aerobic exercise would have to lead to more water loss than resistance training. Beyond just the fact that you USUALLY perspire more during cardio, your average oxygen consumption is also USUALLY higher during the training session, so moisture loss through breathing would also be higher.

I should note that cellular metabolism actually produces 10% of body water, so this will also rise with any exercise in order to partially counteract the deficit.

It truly depends on the intensity of any given exercise bout (assuming all other environmental conditions are the same).

Weightlifting can produce just as much sweat as cardiovascular exercise, it just depends on the intensity.

Kind of a lame answer, but it’s very tough to quantify and come up with anything better to say.