Metcalfe · Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme 2016 · uncontrolled before-after intervention study · n=35

Changes in aerobic capacity and glycaemic control in response to reduced-exertion high-intensity interval training (REHIT) are not different between sedentary men and women.

Cited 70 times in the scientific literature.

Level 4 - case-series / case-control

Uncontrolled prospective before-and-after intervention study.

PubMed 27753506 · doi:10.1139/apnm-2016-0253 · record verified 2026-08-30

What was done

Thirty-five sedentary adults (18 women, 17 men; mean age 36 ± 9 and 33 ± 9 years) completed a 6-week reduced-exertion high-intensity interval training (REHIT) programme. The intervention comprised 18 sessions of 10-minute unloaded cycling (3 times per week) containing 1 to 2 all-out 10-20-second sprints against 5% body mass resistance. Maximal aerobic capacity and oral glucose tolerance test-derived insulin sensitivity were measured pre- and post-intervention to assess whether training adaptations differ between sexes.

What was found

Maximal aerobic capacity increased from 2.54 ± 0.65 to 2.78 ± 0.68 L/min (main effect of time: p < 0.01). Plasma insulin area-under-the-curve showed a non-significant reduction trend (6.7 ± 4.8 vs. 6.1 ± 4.0 IU·min⁻¹·mL⁻¹, p = 0.096). There was no significant change in plasma glucose area-under-the-curve or the Cederholm index of insulin sensitivity. High interindividual variability was observed across all measures, but sex differences were not statistically significant.

Why it matters

This study shows that minimal-commitment REHIT improves aerobic fitness in sedentary adults, with response heterogeneity driven by individual variability rather than participant sex.

Limits

The study lacked a non-exercise control group, had a small sample size (n = 35), lasted only 6 weeks, and did not achieve statistically significant improvements in primary glycemic control endpoints.

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