Muscle fatigue

Muscles become fatigued (tired) during long periods of vigorous activity. This means that they stop contracting efficiently. One cause of this is the build-up of lactic acid in the muscles from anaerobic respiration. The lactic acid is removed from the muscles by blood flowing through them.

Fitness versus health

Fit people are able to carry out physical activities more effectively than unfit people. Their pulse rate is likely to return to normal more quickly after exercise.

But being fit is not the same as being healthy. Healthy people are free from disease and infection - they may or may not be fit as well. It is possible to be fit but unhealthy, or healthy but unfit.

	Created by lmg719 over 11 years ago

Biology (Aerobic and Anaerobic Respiration) Note on Respiration, created by lmg719 on 29/04/2013.