Effects of high-intensity interval training and moderate-intensity continuous training on endothelial function and cardiometabolic risk markers in obese adults

Abstract

We hypothesized that high-intensity interval training (HIIT) would be more effective than moderate-intensity continuous training (MICT) at improving endothelial function and maximum oxygen uptake (V̇o2 max) in obese adults. Eighteen participants [35.1 ± 8.1 (SD) yr; body mass index = 36.0 ± 5.0 kg/m(2)] were randomized to 8 wk (3 sessions/wk) of either HIIT [10 × 1 min, 90-95% maximum heart rate (HRmax), 1-min active recovery] or MICT (30 min, 70-75% HRmax). Brachial artery flow-mediated dilation (FMD) increased after HIIT (5.13 ± 2.80% vs. 8.98 ± 2.86%, P = 0.02) but not after MICT (5.23 ± 2.82% vs. 3.05 ± 2.76%, P = 0.16). Resting artery diameter increased after MICT (3.68 ± 0.58 mm vs. 3.86 ± 0.58 mm, P = 0.02) but not after HIIT (4.04 ± 0.70 mm vs. 4.09 ± 0.70 mm; P = 0.63). There was a significant (P = 0.02) group × time interaction in low flow-mediated constriction (L-FMC) between MICT (0.63 ± 2.00% vs. -2.79 ± 3.20%; P = 0.03) and HIIT (-1.04 ± 4.09% vs. 1.74 ± 3.46%; P = 0.29). V̇o2 max increased (P < 0.01) similarly after HIIT (2.19 ± 0.65 l/min vs. 2.64 ± 0.88 l/min) and MICT (2.24 ± 0.48 l/min vs. 2.55 ± 0.61 l/min). Biomarkers of cardiovascular risk and endothelial function were unchanged. HIIT and MICT produced different vascular adaptations in obese adults, with HIIT improving FMD and MICT increasing resting artery diameter and enhancing L-FMC. HIIT required 27.5% less total exercise time and ∼25% less energy expenditure than MICT.

The influence of high‐intensity interval training on anthropometric variables of adults with overweight or obesity: a systematic review and network meta‐analysis

“…For example, Sawyer et al . observed that MICT sessions resulted in an energy expenditure ~33% higher than that of HIIT; in a study by Kong et al . , the energy expenditure of the MICT sessions was ~102% higher than that of the HIIT sessions.…”

“…In some of these studies, the analyses compared training methods that presented a significant difference in energy expenditure between the sessions (26,27). For example, Sawyer et al (28) observed that MICT sessions resulted in an energy ex-penditure~33% higher than that of HIIT; in a study by Kong et al (29), the energy expenditure of the MICT sessions was~102% higher than that of the HIIT sessions. Thus, review studies must consider analyses that included isocaloric protocols only (30).…”

The effects of high‐intensity interval training vs. moderate‐intensity continuous training on body composition in overweight and obese adults: a systematic review and meta‐analysis

“…Interventions were conducted for 10.4 ± 3.1 weeks (range 5-16 weeks), and the mode of exercise was matched for HIIT and MICT interventions in all studies. Cycle ergometer was the most common modality (seven studies (24,25,27,30,32,34,35)), followed by treadmill running (six studies (23,26,28,29,31,33)).…”

“…All data for whole-body fat levels (N = 11 studies) were drawn from studies applying either DXA (seven studies (24,25,28,31,32,34,35)) or BIA (four studies (23,26,30,33)). Six studies reported whole-body lean mass (four studies using DXA (27,28,34,35) and two studies using BIA (26,30)), four studies reported trunk fat values (three studies using DXA (25,27,35) and one using BIA (30)) and one CT study provided visceral fat as a measure (33).…”

“…Despite clear evidence for the positive adaptations following HIIT compared with MICT with regard to aerobic fitness and vascular function, it is still unclear which form of training is most effective for weight control, overall fat loss or central adiposity. Recent studies have analysed the comparative effectiveness of HIIT and MICT on body fat loss in overweight populations with varying findings (23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35), but a systematic review is yet to be conducted. The aim of this systematic review and meta-analysis was to compare the effectiveness of HIIT and MICT on body weight and body composition outcomes in healthy but overweight or obese adults.…”