Acute Exercise and Appetite-Regulating Hormones in Overweight and Obese Individuals: A Meta-Analysis

Abstract

In lean individuals, acute aerobic exercise is reported to transiently suppress sensations of appetite, suppress blood concentrations of acylated ghrelin (AG), and increase glucagon-like peptide-1 (GLP-1) and peptide-YY (PYY). Findings in overweight/obese individuals have yet to be synthesised. In this systematic review and meta-analysis, we quantified the effects that acute exercise has on AG and total PYY and GLP-1 in overweight/obese individuals. The potential for body mass index (BMI) to act as a moderator for AG was also explored. Six published studies (73 participants, 78% male, mean BMI: 30.6 kg·m^-2) met the inclusion criteria. Standardised mean differences (SMDs) and standard errors were extracted for AG and total PYY and GLP-1 concentrations in control and exercise trials and synthesised using a random effects meta-analysis model. BMI was the predictor in metaregression for AG. Exercise moderately suppressed AG area-under-the-curve concentrations (pooled SMD: -0.34, 95% CI: -0.53 to -0.15). The magnitude of this reduction was greater for higher mean BMIs (pooled metaregression slope: -0.04 SMD/kg·m^-2 (95% CI: -0.07 to 0.00)). Trivial SMDs were obtained for total PYY (0.10, 95% CI: -0.13 to 0.31) and GLP-1 (-0.03, 95% CI: -0.18 to 0.13). This indicates that exercise in overweight/obese individuals moderately alters AG in a direction that could be associated with decreased hunger and energy intake. This trial is registered with PROSPERO: CRD42014006265.

Figure 1

Flowchart of study selection.

Figure 2

Forest plot of effect sizes (means ± 95% confidence intervals [CIs]) for studies evaluating the influence of acute exercise on acylated ghrelin AUC values in overweight and obese individuals.

Figure 3

Univariable metaregression for study mean BMI versus the acylated ghrelin AUC values in response to exercise in overweight and obese individuals SMD for acylated ghrelin. Data shown is pooled from the current review and from a previous review [15]. A negative correlation was observed which persisted even when baseline (control) mean ghrelin concentration was added as a covariate.

Figure 4

Funnel plot of standard error by standard difference in means for studies evaluating the influence of acute exercise on acylated ghrelin AUC values in overweight/obese individuals.

Figure 5

Forest plot of effect sizes (means ± 95% confidence intervals [CIs]) for studies evaluating the influence of acute exercise on total PYY AUC values in overweight and obese individuals.

Figure 6

Forest plot of effect sizes (means ± 95% confidence intervals [CIs]) for studies evaluating the influence of acute exercise on total GLP-1 AUC values in overweight and obese individuals.