Physical activity, sedentary behaviour and sleep: associations with cardiometabolic risk in abdominally obese men and women
McGuire, Karen Ashlee
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Current guidelines suggest that physical activity must be performed at a moderate-to-vigorous intensity (MVPA) and accumulated in bouts of at least 10 consecutive minutes to elicit improvement in cardiorespiratory fitness (CRF). In the first study we sought to determine whether the duration and intensity of objectively measured incidental physical activity (IPA; activity performed below the designated threshold) was associated with CRF in abdominally obese, inactive men (n=43) and women (n=92). Secondary analyses examined the associations between light physical activity (LPA), sporadic moderate physical activity (MPA; accumulated in <10 minute bouts), and CRF. Both duration and intensity of IPA were positively associated with CRF among inactive, abdominally obese adults. Sporadic MPA, but not LPA, was an independent predictor of CRF. Whereas some observations suggest that sedentary behaviour (SED) is negatively associated with health outcomes, other evidence fails to support this notion. The primary aim of the second study was to clarify the relationships between SED, LPA, and MVPA with 2-hour glucose and insulin resistance in inactive adults (43 men, 92 women) with abdominal obesity. Secondary analyses examined the association between SED, LPA, MVPA and other common cardiometabolic risk factors. Neither SED nor the physical activity variables were associated with 2-hour glucose or insulin resistance. SED was not associated with any cardiometabolic risk factor; with the exception of blood pressure, LPA was not associated with any cardiometabolic risk factor; and MVPA was independently associated with total cholesterol and triglycerides. Whether IPA is associated with abdominal obesity is unknown. The purpose of study three was to determine the association between IPA and abdominal adipose tissue depots (visceral adipose tissue and subcutaneous adipose tissue) in inactive men (n=42) and women (n=84). Secondary analyses examined the associations between SED, sleep duration, and caloric intake with abdominal obesity. IPA was not associated with any measure of abdominal obesity, nor was LPA. After control for age and sex, MPA was negatively associated with visceral adipose tissue. SED and sleep duration were not associated with abdominal obesity. Caloric intake was not associated with abdominal obesity after control for age and sex.