The impact of exercise intensity on whole body and adipose tissue metabolism during energy restriction in sedentary overweight men and postmenopausal women

Abstract

This study aimed to establish whether vigorous-intensity exercise offers additional adipose-related health benefits and metabolic improvements compared to energy-matched moderate-intensity exercise. Thirty-eight sedentary overweight men (n = 24) and postmenopausal women (n = 14) aged 52 ± 5 years (mean ± standard deviations [SD]) were prescribed a 3-week energy deficit (29302 kJ∙week-1) achieved by increased isocaloric moderate or vigorous-intensity exercise (+8372 kJ∙week-1) and simultaneous restricted energy intake (-20930 kJ∙week-1). Participants were randomly assigned to either an energy-matched vigorous (VIG; n = 18) or moderate (MOD; n = 20) intensity exercise group (five times per week at 70% or 50% maximal oxygen uptake, respectively). At baseline and follow-up, fasted blood samples and abdominal subcutaneous adipose tissue biopsies were obtained and oral glucose tolerance tests conducted. Body mass was reduced similarly in both groups (∆ 2.4 ± 1.1 kg and ∆ 2.4 ± 1.4 kg, respectively, P < 0.05). Insulinemic responses to a standard glucose load decreased similarly at follow-up relative to baseline in VIG (∆ 8.6 ± 15.4 nmol.120 min.l-1) and MOD (∆ 5.4 ± 8.5 nmol.120 min.l-1; P < 0.05). Expression of SREBP-1c and FAS in adipose tissue was significantly down-regulated, whereas expression of PDK4 and hormone-sensitive lipase (HSL) was significantly up-regulated in both groups (P < 0.05). Thus, when energy expenditure and energy deficit are matched, vigorous or moderate-intensity exercise combined with energy restriction provide broadly similar (positive) changes in metabolic control and adipose tissue gene expression.

Keywords: Adipose tissue; energy restriction; exercise intensity; gene expression; metabolism.

© 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Figures

Figure 1

Serum insulin 2 h iAUC (A) for the MOD group (n = 15) and the VIG group (n = 14), plasma glucose 2 h iAUC (B; means ± CI) for the MOD group (n = 16) and the VIG group (n = 12) before and after 3 weeks of energy restriction with moderate‐intensity or vigorous‐intensity physical exercise. There were technical problems with the cannula on a few occasions and this explains the reduced sample size for some outcomes. † denotes a main effect of day (P = 0.005) * denotes a dayxgroup interaction (P = 0.04). The dotted line denotes the individual data points from women while the continuous line denotes the individual data points from men.

Figure 2

Relative gene expression of several key genes measured in adipose tissue at baseline and follow‐up for the MOD group (n = 12) and the VIG group (n = 12). Dashed line represents no change. Data normalized to PPIA, baseline, and internal calibrator. Any change score (normalized follow‐up data vs. normalized baseline data) that was over 3 SD from the mean (11 data points out of 360) were excluded from the presentation shown in this Figure, but were included in the statistical analysis which used the logged values. Samples outside the detectable limit (Ct>35; n = 8) were excluded from the analysis. FAS (MOD, n = 11), IL18 (MOD, n = 8), IL6 (MOD, n = 9; VIG, n = 11). Values are means ± SEM. † main effect of day (i.e., Day 1 vs. Day 21 both groups; P ≤ 0.05).