Burning and Cooling

Metabolism and sweat

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Muscles are about 25% efficient. The rest of the energy becomes heat.
• Evaporating sweat absorbs about 2.4 MJ per kg.
• Hard exercise can demand close to a litre of sweat per hour.

Steps

1. An inefficient engine
2. Mechanical work
3. A day at rest
4. Why a fan cools you
5. How much sweat?
6. Sweat for one ride