EXERCISE

• • During exercise, the body needs a great deal of energy for muscle contraction and the body has to react to this increased demand for energy
  • As the body needs more energy, aerobic respiration increases meaning that the body cells require more oxygen
  • To provide for this extra oxygen, both the breathing rate and breathing volume increases - we breathe more frequently and we take deeper breaths, getting more oxygen into the blood stream
• • To provide for the extra oxygen, the heart rate also increases to pump this oxygenated blood around the body
  • Sometimes, not enough oxygen can be supplied to the muscles, especially if we are exercising hard
  • At this point, anaerobic respiration now takes place in the muscles
• • During anaerobic respiration, the oxidation of glucose is incomplete, this leads up to a build up of the chemical lactic acid
• • During long periods of vigorous activity, lactic acid causes the muscles to become fatigued, causing the muscles to stop contracting efficiently
  • At this point, the body has to remove lactic acid from the muscles creating a condition called the oxygen debt