Aerobic work capacity and plasma FFA turnover

Mongrel dogs with indwelling arterial and venous catheters ran on a treadmill at a speed of 100 m/min and a grade of 15°. Palmitate-i-C14 was infused at a constant rate; the rate of release and the rate of removal of the plasma FFA were calculated. During exercise the O2 uptake was about the same in all animals, but the rate of increase of the blood lactate varied widely according to the physical condition of the animal. ThereΔ was a negative correlation (P <.001) between the changes in the rate of release of FFA (Δ µEq/ kg min) and the rate of increase of lactate. If this latter exceeded 58 mg/100 ml in 30 min, the FFA turnover decreased below the resting level. Since it is known that lactate infusion in itself decreases the release of FFA, it is concluded that the rise of blood lactate during exercise, which reflects the state of aerobic work capacity, is an important factor affecting the participation of the adipose tissue in the exercise metabolism. exercise and FFA; physical fitness and FFA; blood lactate and FFA Submitted on April 27, 1964