Effects of Hypoxic Compound Exercise to Promote HIF-1α Expression on Cardiac Pumping Function, Sleep Activity Behavior, and Exercise Capacity in Drosophila

Alteration of HIF-1 alpha expression levels under hypoxic conditions affects the sequence of its downstream target genes thereby producing different effects. In order to investigate whether the effect of hypoxic compound exercise (HE) on HIF-1 alpha expression alters cardiac pumping function, myocardial structure, and exercise capacity, we developed a suitable model of hypoxic exercise using Drosophila, a model organism, and additionally investigated the effect of hypoxic compound exercise on nocturnal sleep and activity behavior. The results showed that hypoxic compound exercise at 6% oxygen concentration for five consecutive days, lasting 1 h per day, significantly improved the cardiac stress resistance of Drosophila. The hypoxic complex exercise promoted the whole-body HIF-1 alpha expression in Drosophila, and improved the jumping ability, climbing ability, moving speed, and moving distance. The expression of HIF-1 alpha in the heart was increased after hypoxic exercise, which made a closer arrangement of myofilaments, an increase in the diameter of cardiac tubules, and an increase in the pumping function of the heart. The hypoxic compound exercise improved the sleep quality of Drosophila by increasing its nocturnal sleep time, the number of deep sleeps, and decreasing its nocturnal awakenings and activities. Therefore, we conclude that hypoxic compound exercise promoted the expression of HIF-1 alpha to enhance the exercise capacity and heart pumping function of Drosophila, and improved the quality of sleep.