Context/purpose Observational and acute laboratory intervention research has shown that excessive sedentary time is associated adversely with cardiometabolic biomarkers. This systematic review with meta-analyses synthesises results from free living interventions targeting reductions in sedentary behaviour alone or combined with increases in physical activity.
Methods Six electronic databases were searched up to August 2019 for sedentary behaviour interventions in adults lasting for ≥7 days publishing cardiometabolic biomarker outcomes covering body anthropometry, blood pressure, glucose and lipid metabolism, and inflammation (54 studies). The pooled effectiveness of intervention net of control on 15 biomarker outcomes was evaluated using random effects meta-analyses in the studies with control groups not providing other relevant interventions (33 studies; 6–25 interventions analysed).
Results Interventions between 2 weeks and <6 months in non-clinical populations from North America, Europe and Australia comprised much of the evidence base. Pooled effects revealed small, significant (p<0.05) beneficial effects on weight (≈ −0.6 kg), waist circumference (≈ −0.7 cm), percentage body fat (≈ −0.3 %), systolic blood pressure (≈ −1.1 mm Hg), insulin (≈ −1.4 pM) and high-density lipoprotein cholesterol (≈ 0.04 mM). Pooled effects on the other biomarkers (p>0.05) were also small, and beneficial in direction except for fat-free mass (≈ 0.0 kg). Heterogeneity ranged widely (I2=0.0–72.9).
Conclusions Our review of interventions targeting sedentary behaviour reductions alone, or combined with increases in physical activity, found evidence of effectiveness for improving some cardiometabolic risk biomarkers to a small degree. There was insufficient evidence to evaluate inflammation or vascular function. Key limitations to the underlying evidence base include a paucity of high-quality studies, interventions lasting for ≥12 months, sensitive biomarkers and clinical study populations (eg, type 2 diabetes).
PROSPERO trial registration number CRD42016041742
- physical activity
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NTH and EW contributed equally.
Correction notice This article has been corrected since it published Online First. The data and formatting in the tables have been updated.
Contributors All authors reviewed the systematic review strategy. LR executed the searches. PCD, NTH, REC, MSG and EW conducted the review and screened the initial results using standardised rules created a priori. PCD, NTH, REC and EW appraised the studies and extracted data from the primary studies and EW analysed the penultimate results. PCD, NTH and EW drafted the manuscript and all authors contributed to the critical revision of the manuscript and approved the final revised version. PCD is the guarantor.
Funding PCD is supported by a National Health and Medical Research Council (NHMRC) of Australia Fellowship (#1142685) and the UK Medical Research Council [MC_UU_12015/3]. NO, DD and GH are supported by NHMRC of Australia Fellowships (#1003960, #1078360 & #1086029).
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.