Human speed statements

When you do intense exercise, you breathe faster and your heart goes faster.

After a few minutes, acids like lactic acid build up in the muscles.

If you make too much effort, your body stops working properly.

During exercise, the breakdown of carbohydrate and fat produces a chemical that moves muscles.

When running fast, you cannot breathe quickly enough to get enough oxygen.

You need to eat a lot of meat and other proteins to prepare for exercise.

Drugs like anabolic steroids have long-term positive effects on your health.

Cheetahs can run more than three times as fast as humans.