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-1) or fasting insulin (95% CI: −1.79 to 9.85 pmol·L-1) 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-1; 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 (HbA1c) (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.
- exercise intensity
- physical activity
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Contributors PS, MIK, NT, BAG: contributed to the development of the research questions, study design and literature search strategy. PS: conducted the literature search. PS, MIK, NT, BAG: reviewed articles and performed study selection. PS, BG: performed methodological quality assessment and data extraction. PS, MIK, NT, BAG: contributed to data interpretation. PS: drafted the manuscript. MIK, NT, BAG: provided critical review. All authors read and approved the final manuscript.
Funding PS was supported by an Australian Government Research Training Program Scholarship. The authors have not declared any other grant from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent Not required.
Provenance and peer review Not commissioned; internally peer reviewed.