Does Sweating More Make for a Better Workout?

You Should Know: Leaving a workout class completely drenched while your friend beside you barely broke a sweat doesn’t necessarily mean you burned more calories. Perspiration is the body’s cooling system, and the amount of water and salt you produce has far more to do with your body and environment than with how hard you’re actually pushing.

Going Deeper: Research on hot yoga found that a 90-minute class burned around 330 to 460 calories on average — nowhere near the 1,000-per-hour figure that sometimes gets floated online. You can also burn plenty of calories swimming or exercising in cold weather without breaking much of a sweat. Interestingly, fitter people tend to sweat sooner into a workout because their bodies get more efficient at cooling down, so heavy sweating can actually reflect good conditioning even when it has nothing to do with calorie burn.

Takeaway: Heart rate is a much better gauge if you’re trying to determine how hard you’re working. On particularly hot days, that might mean slowing your pace or lowering the intensity to keep it in your usual range.

Bottom Line: Sweat doesn’t mean all that much when it comes to calories burned or effort level.