Oxygen consumption, substrate oxidation, and blood pressure following sprint interval exercise

This study examined the acute effect of sprint interval exercise (SIE) on postexercise oxygen consumption, substrate oxidation, and blood pressure. The participants were 10 healthy males aged 21-27 years. Following overnight fasts, each participant undertook 2 trials in a random balanced order: (i) four 30-s bouts of SIE on a cycle ergometer, separated by 4.5 min of recovery, and (ii) resting (control) in the laboratory for an equivalent period. Time-matched measurements of oxygen consumption, respiratory exchange ratio, and blood pressure were made for 2 h into recovery. Total 2-h oxygen consumption was significantly higher in the SIE than in the control trial (mean +/- SD: Control: 31.9 +/- 6.7 L vs Exercise: 45.5 +/- 6.8 L, p < 0.001). The rate of fat oxidation was 75% higher 2 h after the exercise trial compared with the control trial (Control: 0.08 +/- 0.05 g.min(-1) vs Exercise: 0.14 +/- 0.06 g.min(-1), p = 0.035). Systolic blood pressure (Control: 117 +/- 8 mmHg vs Exercise: 109 +/- 8 mmHg, p < 0.05) and diastolic blood pressure (Control: 84 +/- 6 mm Hg vs Exercise: 77 +/- 5 mm Hg, p < 0.05) were significantly lower 2 h after the exercise trial compared with the control trial. These data showed a 42% increase in oxygen consumption (similar to 13.6 L) over 2 h after a single bout of SIE. Moreover, the rate of fat oxidation increased by 75%, whereas blood pressure was reduced by similar to 8 mm Hg 2 h after SIE. Whether these acute benefits of SIE can translate into long-term changes in body composition and an improvement in vascular health needs investigation.