Rasvapõletustsoon (pulsivahemik)

Although the lipolytic rate remains relatively high with increasing exercise intensity, the release of fatty acids into the circulation declines

(measured as the rate of appearance of fatty acids in plasma). This might seem counterproductive, reducing the availability of an energy-rich source of fuel at a time when energy demands are reaching their maximum but, during high-intensity exercise, muscles rely predominantly on intramuscular stores of carbohydrate and fat. In fact, even when lipids were infused intravenously during high-intensity exercise to increase plasma fatty

acid concentrations to very high levels (1–2 mM), the rate of fat oxidation was still less than that seen at lower exercise intensities [5]. The mechanism responsible for this reduction in fatty acid mobilization is not known. However, because plasma fatty acid concentrations increase dramatically immediately after intense exercise, it has been hypothesized that the reduction in fatty acid release into the circulation might result from a restriction in adipose tissue blood flow, mediated by catecholamine-stimulated vasoconstriction in adipose tissue blood vessels.