response to exercise

• All organisms respire in order to release energy to fuel their living processes.
• The respiration can be aerobic, which uses glucose and oxygen, or anaerobic which uses only glucose.
• While exercising, the muscles need additional energy as the breathing rate and volume of each breath increases to bring more oxygen into the body and remove the carbon dioxide produced.
• The heart rate increases, to supply the muscles with extra oxygen and remove the carbon dioxide produced.
• If insufficient oxygen is available to the muscles, for instance the exercise is vigorous and/or prolonged, the heart and lungs are unable to supply sufficient oxygen.
• Muscles begin to respire anaerobically.
• Lactic acid is produced from glucose, instead of carbon dioxide and water.
• Muscles continue to contract, but less efficiently.
• During long periods of vigorous activity, lactic acid levels build up.
• Glycogen stores in the muscles become low as more glucose is used for respiration, and additional glucose is transported from the liver.
• This build-up of lactic acid produces an oxygen debt.
• The amount of extra oxygen required by the body for recovery after vigorous exercise is known as the oxygen debt.
• As body stores of glycogen become low, the person suffers from muscle fatigue.