Resting Metabolic Rate Does Not Change in Response to Different Types of Training in Subjects with Type 2 Diabetes

Abstract

Background and objectives: Ambiguous results have been reported regarding the effects of training on resting metabolic rate (RMR), and the importance of training type and intensity is unclear. Moreover, studies in subjects with type 2 diabetes (T2D) are sparse. In this study, we evaluated the effects of interval and continuous training on RMR in subjects with T2D. Furthermore, we explored the determinants for training-induced alterations in RMR.

Methods: Data from two studies, both including T2D subjects, were encompassed in this manuscript. Study 1 was a randomized, crossover study where subjects (n = 14) completed three, 2-week interventions [control, continuous walking training (CWT), interval-walking training (IWT)] separated by washout periods. Training included 10 supervised treadmill sessions, 60 min/session. CWT was performed at moderate walking speed [aiming for 73% of walking peak oxygen uptake (VO2peak)], while IWT was performed as alternating 3-min repetitions at slow (54% VO2peak) and fast (89% VO2peak) walking speed. Study 2 was a single-arm training intervention study where subjects (n = 23) were prescribed 12 weeks of free-living IWT (at least 3 sessions/week, 30 min/session). Before and after interventions, RMR, physical fitness, body composition, and glycemic control parameters were assessed.

Results: No overall intervention-induced changes in RMR were seen across the studies, but considerable inter-individual differences in RMR changes were seen in Study 2. At baseline, total body mass (TBM), fat-free mass (FFM), and fat mass were all associated with RMR. Changes in RMR were associated with changes in TBM and fat mass, and subjects who decreased body mass and fat mass also decreased their RMR. No associations were seen between changes in physical fitness, glycemic control, or FFM and changes in RMR.

Conclusion: Neither short-term continuous or interval-type training, nor longer term interval training affects RMR in subjects with T2D when no overall changes in body composition are seen. If training occurs concomitant with a reduction in fat mass, however, RMR is decreased.

Clinical trials registration wwwclinicaltrialsgov: NCT02320526 and NCT02089477.

Keywords: body composition; diabetes type 2; exercise interventions; exercise training; glycemic control; physical fitness; resting metabolic rate.

Figures

Figure 1

The effect of training interventions on resting metabolic rate (RMR). Subjects with type 2 diabetes underwent three 2-week interventions (A–C); no training [control (CON)], continuous walking training (CWT), interval-walking training [IWT or 12 weeks of IWT training (D–F)]. RMR was measured before and after interventions and is reported as total RMR (A,D), RMR relative to total body mass [TBM (B,E)] and RMR relative to fat-free mass [FFM (C,F)]. Data are shown as mean ± SEM (A–C) and mean + individual data (D–F). Statistical analyses [two-way repeated-measures ANOVA in Panels (A–C)] and Student’s paired t-test (D–F) did not result in any significant changes within interventions (p > 0.05 for all comparisons).

Figure 2

Baseline associations between resting metabolic rate (RMR) and potential determinants of RMR. Simple regression analyses were performed between baseline values of potential determinants of RMR (x-axis) and baseline RMR (y-axis). The potential determinants were VO2max [absolute, relative to total body mass (TBM), and relative to fat-free mass (FFM) (A–C)], body composition [body mass, FFM, and fat mass (D–F)] and glycemic control [fasting glucose, mean oral glucose tolerance test (OGTT) glucose, and 2 h OGTT glucose (G–I)]. Data from both Study 1 (open circles) and Study 2 (black circles) were included in the regression analyses and results (β-coefficients, r2-, and p-values) are given in each panel.

Figure 3

Associations between delta (post minus pre intervention) values of resting metabolic rate (RMR) and delta values of potential determinants of RMR. Simple regression analyses were performed between delta values of potential determinants of RMR (x-axis) and delta values of RMR (y-axis). The potential determinants were VO2max [absolute, relative to total body mass (TBM) and relative to fat-free mass (FFM) (A–C)], body composition [body mass, FFM and fat mass (D–F)] and glycemic control [fasting glucose, mean oral glucose tolerance test (OGTT) glucose, and 2 h OGTT glucose (G–I)]. Data from Study 2 were included in the regression analyses and results (β-coefficients, r2-, and p-values) are given in each panel.

Figure 4

Stratified analyses of potential determinants for resting metabolic rate (RMR). Subjects included in Study 2 were stratified according to their change in RMR as increased RMR (≥10%, n = 7), unchanged RMR (n = 9), or decreased RMR (≥10%, n = 7). Delta (post minus pre intervention) values ± SEM of potential determinants for RMR {VO2max [absolute, relative to total body mass (TBM), and relative to fat free mass (FFM); panel (A–C)], body composition [body mass, fat free mass, and fat mass; panel (D–F)], and glycemic control [fasting glucose, mean OGTT glucose, and 2 h OGTT glucose; panel (G–I)]} are shown for the different strata. Within-strata changes in potential determinants of RMR were analyzed by two-way (strata × time) repeated-measures (RM) ANOVA (significant changes indicated by an asterisk above the bar) and between-strata differences were analyzed by one-way RM ANOVA of the delta values (significant changes indicated by a connecting line and an asterisk).