The effect of breaking up sedentary time on cardiometabolic disease risk markers in South Asian adults
AuthorsDey, Kamalesh Chandra
metabolic load index
Subject Categories::C600 Sports Science
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AbstractSouth Asians are at higher risk of developing cardiometabolic disease, including cardiovascular diseases (CVD) and Type 2 diabetes than any other ethnicities (e.g., Caucasians) in the UK. Engaging with a high sedentary behaviour could contribute to these diseases as sedentary behaviour is associated with developing CVD and Type 2 diabetes. The primary aim of this thesis was to investigate the effects of breaking up sedentary time on cardiometabolic disease risk markers and metabolic health in South Asians. This thesis presents four novel inter-related studies, included a systematic review and three acute experimental studies in controlled laboratory and free-living settings. In study one (chapter 4), a systematic review reported total sedentary time in South Asians. The key finding is that South Asians engage in a mean daily sedentary time of approximately 7 h (424 ± 8 min). Daily sedentary time appears to be higher by 111 min when measured using objective methods (527 ± 11 min) than self-report methods (416 ± 19 min). Study two (chapter 5) and three (chapter 6) employed a two-condition randomised cross-over design and identical methods in normal-weight and overweight/obese South Asians, respectively. In the normal-weight South Asians (study two), breaking up sedentary time with 5 min bouts of self-perceived light-intensity walking (LPA) every 30 min following a high glycaemic index (GI) breakfast and lunch only improved postprandial triglyceride (TAG) concentrations over 5 h when compared with prolonged sitting, whereas the overweight/obese South Asians (study three) benefited from attenuated postprandial glucose, TAG, and metabolic load index (MLI) over 5 h (but not the area under the curve (AUC)), and increased postprandial resting energy expenditure (REE), and overall fat and carbohydrate (CHO) oxidation. No effects were observed for plasma insulin, mean arterial pressure (MAP), and heart rate in either group. Data from studies two and three suggest that the cardiometabolic health benefit of breaking up sedentary time with LPA can be generalised to a wider range of cardiometabolic variables (e.g., postprandial glucose) in overweight/obese versus normal-weight South Asians, possibly due to having a higher percentage of body fat composition than normal-weight South Asians. Study four (chapter 7) findings revealed that it was possible to manipulate overweight/obese South Asian adults’ sedentary time and physical activity (PA) levels in free-living conditions over 4 days, but continuously measured glucose responses were unaffected by such manipulations. To summarise, South Asians appear to engage in a high volume of sedentary time habitually, which could compromise their cardiometabolic health. Breaking up sedentary time with 5 min bouts of LPA every 30 min can acutely improve some cardiometabolic risk markers in normal-weight and overweight/obese South Asians in a controlled laboratory setting. In free-living settings, reducing and breaking up sedentary time does not appear to affect continuously measured glucose responses in overweight/obese South Asians. The studies within this thesis were novel due to the population; thus, this is the first time these findings have been reported. Reducing and breaking up sedentary time could play a crucial role in improving cardiometabolic health in this under-researched population in the short term. Further research should investigate the effectiveness of reducing and breaking up sedentary time in long-term interventions for improving cardiometabolic health in the South Asian population.
CitationDey, K.C.(2022) The Effect of Breaking up Sedentary Time on Cardiometabolic Disease Risk Markers in South Asian Adults. PhD thesis. University of Bedfordshire.
PublisherUniversity of Bedfordshire
TypeThesis or dissertation
DescriptionA thesis submitted to the University of Bedfordshire, in partial fulfilment of the requirements for the degree of Doctor of Philosophy.
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