Muscle blood flow and oxygen uptake in recovery from exercise.

The metabolic and muscle blood flow response in recovery from exercise is dependent on the type and the duration of the exercise. Immediately after both intense static and dynamical exercise blood flow to the exercised muscles increases suggesting that blood flow is mechanically hindered by muscle contraction. After the initial rise (seconds) muscle blood flow decreases at a moderate rate and the time to reach resting flow levels varies from seconds to more than 30 min. It is unclear as to what causes the elevated blood flow during recovery. A mismatch between the time course of changes in blood flow and oxygen uptake suggests that the blood flow is not directly regulated by the need of oxygen in the exercised muscles. The hyperaemic response may be linked to locally released factors, such as ions and metabolites. However, the signal by which the blood flow is elevated remains unknown. After exercise both pulmonary and muscle oxygen uptake decrease rapidly, but can remain above resting levels for several hours. Resynthesis of substrates such as CP, ATP and glycogen cannot account for the entire excessive post-exercise oxygen uptake (EPOC) in the exercised muscles and the cause of the elevated muscle oxygen uptake in recovery from exercise remains to be assessed.