Sprint interval training protocol
muscle mass, nausea, 75‐gram glucose
HEART
Participants completed in random order, 5 days apart, no exercise (control, resting group) or SIT performed on a cycle ergometer (Monark 894 E, Monark, Varberg, Sweden). After a baseline measure, 12 min (4 min for SIT and 8 min for recovery interval) of exercise was performed 90‐min after an oral 75‐gram glucose load. Sessions consisted of eight‐repeated 30‐s “all‐out” efforts on a manual braked cycle ergometer against a resistance equivalent to 0.075 kg/kg muscle mass (i.e., a Wingate test). Participants were instructed to begin pedaling as fast as possible against the ergometer's inertial resistance, ∼2 s before the appropriate load was applied, and were verbally encouraged to continue pedaling as fast as possible throughout the 30‐s test. During the 1‐min recovery period between tests, they remained seated on the ergometer and either rested or were permitted to cycle at a low cadence (50 to 60 revolutions/rotations per minute) against a light resistance (~50 W) to reduce venous pooling in the lower extremities and minimize feelings of light‐headedness or nausea.Prior to test, the maximal heart rate was calculated as 220 minus age. The target exercise intensity for each individual was 90%–95% of the estimated maximal heart rate. Heart rate was monitored continuously during cycling using a wireless chest‐strap monitor (Polar A300, Polar, Denmark). Each interval and resistance was varied as needed to maintain the heart rate within a range of ±5 beats/min of the target heart rate. As shown in Figure 