Answer:
Person starts to exercise.
Skeletal muscle oxygen demand increase  
Skeletal muscle metabolism increases
.Blood delivery to the skeletal muscle increases is order to provide more oxygen  
Oxygen sensors cause local blood cell vessels to dilate
.
This steps briefly describe the physiology of exercise. 
At the onset of exercise,  skeletal muscles cells were sustained with  available oxygen from the Myoglobin. Myoglobin is  oxygen binding and storage  protein found in cardiac and skeletal muscles cells.  it has high storing capacity for oxygen.
However as the exercise becomes intense ATPs supply drops, oxygen  demand increases,cellular metabolisms demand also increase to supply glucose and ATP to the cells. 
 The liver mediates Gluconeogenesis.  Fatty acid is broken down to glucose for cellular respiration  with' ketone bodies  build up..Exercise also stimulates the breakdown of muscle glycogen to glucose,  Therefore, cellular respiration takes place to break down the glucose to  C02, H20  and energy with rise in temperature.
However, oxygen concentration is  low, therefore muscles cells undergo anaerobic respiration with lactic acid pathway. Lactic  acid  build up in muscles cells.The muscles cells under go oxygen debt to break down  lactic acid  to glucose in muscle.
Therefore to adjust the mechanism oxygen homeostatic sensors increases hyperventilation to increase  oxygen intake through the lungs, and vasodilation. so that maximum volume of blood containing oxygen is transported to muscles cells; to sustain the intense activity
  
  
Explanation: