Turnover of free fatty acids during recovery from exercise

The turnover of plasma free fatty acid (FFA) was studied during the recovery from exercise with the aid of a continuous infusion of 14C-labeled oleic acid. Arterial FFA reached a maximum of twice the exercise value after 6 min of recovery and was still 75% above the basal level after 20 min. Within 2 min after exercise, plasma radioactivity had increased and the specific activity of plasma oleic acid had fallen. The rate of uptake of FFA from the plasma pool rsoe by 40% during the first minutes after exercise. The rate of release of FFA to the plasma pool showed a peak 2 min after exercise and was thereafter about 40 mumol/min lower than the rate of uptake. The fractional turnover of FFA decreased to resting levels within 5-10 min after exercise. It is concluded that the postexercise peak in arterial FFA is a consequence of augmented release of FFA into the plasma pool above the level during exercise, possibly related to the release of sympathetic vasoconstrictor tone. As a consequence, the rate of removal of FFA rises at the end of exercise and remains augmented above the basal level for as long as the arterial concentration is increased.