Accumulated or continuous exercise for glycaemic regulation and control: a systematic review with meta-analysis.

Objective: To compare the effectiveness of accumulating exercise in multiple bouts of at least 10 min throughout a day with exercise completed in a single bout (continuous or interval), or no exercise, on glycaemic control and regulation in inactive people without diagnosed glycaemic dysfunction.

Design: Systematic review and meta-analysis.

Data Sources: Seven electronic databases were searched: CINAHL (EBSCO), Cochrane Library, EMBASE (Ovid), MEDLINE 1948-(Ovid), SCOPUS (Elsevier), SPORTDiscus (EBSCO) and Web of Science (ISI) with no restrictions on date and included all titles indexed up to February 2018.

Eligibility Criteria For Selecting Studies: Articles reporting insufficiently active adults (19 to 64 years) without metabolic dysfunction, measuring glycaemic control or regulation following at least 6 weeks of aerobic exercise.

Results: Only one study compared accumulated exercise to single-bout exercise with no significant effect on fasting glucose (95% CI: -0.04 to 0.24 mmol·L) or fasting insulin (95% CI: -1.79 to 9.85 pmol·L) reported 48 hours after the final bout. No studies compared accumulated exercise with no-exercise. Compared with no-exercise, single-bout exercise reduces insulin resistance (mean difference (MD): -0.53 pmol·L; 95% CI: -0.93 to -0.13). Insulin resistance was clearly reduced with moderate-intensity (-0.68 (-1.28 to -0.09)) but not with high-intensity (-0.38 (-1.20 to 0.44)) exercise. Single-bout exercise was not statistically more beneficial than no-exercise for glycated haemoglobin (HbA) (MD: -0.11 %; 95% CI: -0.24 to 0.02) in metabolically healthy individuals.

Summary/conclusion: The glycaemic response to accumulated exercise or single-bout exercise might not be different, however exercise intensity might influence the mechanisms generating the response.

Prospero Registration Number: CRD42015025042.