Purpose: This study aimed to investigate the effects of a single session of sprint interval training (SIT) and a single extended sprint (ES), matched for total work, on metabolic health biomarkers.
Methods: Ten overweight/obese men aged 26.9±6.2years participated. Following a pre-trial incremental exercise test and SIT familiarization, each participant undertook three 2-day trials in randomized order. On Day 1 participants either undertook no exercise (CON), four maximal 30-s sprints, with 4.5min recovery between each (SIT), or a single maximal extended sprint (ES) matched with SIT for work done. On Day 2, participants had a fasting blood sample taken, undertook an oral glucose tolerance test to determine insulin sensitivity index (ISI), and had blood pressure measured.
Results: Total work done during exercise did not differ between SIT and ES (61.7±2.9 vs. 61.3±2.8kJ; p=0.741). Mean power was higher in SIT than ES (518±21 vs. 306±16W, p<0.0005), resulting in a shorter high-intensity exercise duration in SIT (120±0 vs. 198±10s, p<0.0005). ISI was 44.6% higher following ES than CON (9.4±2.1 vs. 6.5±1.3; p=0.022), but did not differ significantly between SIT and CON (6.6±0.9 vs. 6.5±1.3; p=0.208). However, on the day following exercise fat oxidation in the fasted state was increased by 63% and 38%, compared to CON, in SIT and ES, respectively (p<0.05 for both), with a concomitant reduction in carbohydrate oxidation (p<0.05).
Conclusion: A single ES, which may represent a more time-efficient alternative to SIT, can increase insulin sensitivity and increase fat oxidation in overweight overweight/obese sedentary men.
Copyright © 2013 Elsevier Inc. All rights reserved.