Date Published: June 13, 2019
Publisher: Public Library of Science
Author(s): Paul Mackie, Ishanka Weerasekara, Gary Crowfoot, Heidi Janssen, Elizabeth Holliday, David Dunstan, Coralie English, Deirdre Dawson.
The objective of this review was to ascertain the scope of the available literature on the effects of interrupting prolonged sitting time with frequent bouts of physical activity or standing on stroke and recurrent stroke risk factors. Databases Medline, Embase, AMED, CINAHL and Cochrane library were comprehensively searched from inception until 21st February 2018. Experimental trials which interrupted sitting time with frequent bouts of physical activity or standing in adults (≥ 18 years) were included. Comparison to a bout of prolonged sitting and a measure of at least one first or recurrent stroke risk factor was required to be included. Overall, 30 trials (35 articles) were identified to meet the inclusion criteria. Fifteen trials were completed in participants at an increased risk of having a first stroke and one trial in participants at risk of a recurrent stroke. Outcomes of hypertension and dysglycemia were found to be more favourable following predominately light- to moderate-intensity bouts of physical activity or standing compared to sitting in the majority of trials in participants at risk of having a first stroke. In the one trial of stroke survivors, only outcomes of hypertension were significantly improved. These findings are of significant importance taking into consideration hypertension is the leading risk factor for first and recurrent stroke. However, trials primarily focused on measuring outcomes of dysglycemia and without assessing a dose-response effect. Additional research is required on the dose-response effect of interrupting sitting with frequent bouts of physical activity or standing on first and recurrent stroke risk factors, in those high risk population groups.
Engaging in high levels of sitting is associated with detrimental risks of all-cause mortality, cardiovascular disease and diabetes [1–3]. Spending > 8 hours/day in sitting and engaging in < 2.5 metabolic equivalents (MET—defined by Jette et al.  as “the amount of oxygen consumed while sitting at rest and is equal to 3.5 ml O2/kg/min”) hours/week of physical activity accounts for a 59% increase in all-cause mortality relative to individuals who sit < 4 hours/day and engage in > 35.5 MET hours/week .
The methodological framework by Arksey and O’Malley  and further recommendations from Levac et al.  were utilised in this scoping review. The stages underpinning the review were: (I) identifying the research question, (II) identifying relevant studies, (III) study selection, (IV) charting the data, and (V) collating, summarising, and reporting the results. The quality of studies was not assessed in this review as per recommendations by Arksey and O’Malley .
A total of 29 trials (33 articles) were identified in our search as meeting all inclusion criteria (Fig 1). One (two articles [20, 30]) additional trial was included on the 13th June 2018. Therefore, a total of 30 trials (35 articles) were included in this review, of which 53% were not registered with a trial registry.
This review has synthesised available evidence regarding the effect of interrupting prolonged sitting with frequent bouts of physical activity or standing on risk factors for first or recurrent stroke. A total of 15 trials recruited participants at risk of first stroke (overweight/obese, type 2 diabetes, postmenopausal women/older adults) and one trial in participants at risk of recurrent stroke (one trial; stroke survivors). Four key first or recurrent stroke risk factors (hypertension, hypercholesterolaemia, dysglycemia and weight loss) were measured. In populations identified at high risk of first or recurrent stroke, interrupting prolonged sitting with frequent bouts of physical activity or standing tended to show beneficial effects on outcomes associated with hypertension and dysglycemia, but not on hypercholesterolaemia and weight loss.