Objectively Measured Light-Intensity Physical Activity Is Independently Associated With 2-h Plasma Glucose

Abstract

OBJECTIVE -We examined the associations of objectively measured sedentary time, lightintensity physical activity, and moderate-to vigorous-intensity activity with fasting and 2-h postchallenge plasma glucose in Australian adults.RESEARCH DESIGN AND METHODS -A total of 67 men and 106 women (mean age Ϯ SD 53.3 Ϯ 11.9 years) without diagnosed diabetes were recruited from the 2004 -2005 Australian Diabetes, Obesity, and Lifestyle (AusDiab) study. Physical activity was measured by Actigraph accelerometers worn during waking hours for 7 consecutive days and summarized as sedentary time (accelerometer counts/min Ͻ100; average hours/day), light-intensity (counts/ min 100-1951), and moderate-to vigorous-intensity (counts/min Ն1,952). An oral glucose tolerance test was used to ascertain 2-h plasma glucose and fasting plasma glucose.RESULTS -After adjustment for confounders (including waist circumference), sedentary time was positively associated with 2-h plasma glucose (b ϭ 0.29, 95% CI 0.11-0.48, P ϭ 0.002); light-intensity activity time (b ϭ Ϫ0.25, Ϫ0.45 to Ϫ0.06, P ϭ 0.012) and moderate-to vigorous-intensity activity time (b ϭ Ϫ1.07, Ϫ1.77 to Ϫ0.37, P ϭ 0.003) were negatively associated. Light-intensity activity remained significantly associated with 2-h plasma glucose following further adjustment for moderate-to vigorous-intensity activity (b ϭ Ϫ0.22, Ϫ0.42 to Ϫ0.03, P ϭ 0.023). Associations of all activity measures with fasting plasma glucose were nonsignificant (P Ͼ 0.05).CONCLUSIONS -These data provide the first objective evidence that light-intensity physical activity is beneficially associated with blood glucose and that sedentary time is unfavorably associated with blood glucose. These objective data support previous findings from studies using self-report measures, and suggest that substituting light-intensity activity for television viewing or other sedentary time may be a practical and achievable preventive strategy to reduce the risk of type 2 diabetes and cardiovascular disease. Diabetes Care 30:1384-1389, 2007C hronic high blood glucose concentrations (hyperglycemia) are both a characteristic and a precursor of type 2 diabetes (1). Hyperglycemia is also associated with an increased risk of cardiovascular disease and premature mortality, and this association persists below the categorical cutoffs for diabetes and impaired glucose tolerance (2-5). Understanding the association of modifiable type 2 diabetes risk factors with blood glucose across the glucose range can inform the development of population strategies for reducing the risk of diabetes and other cardiovascular diseases.Physical activity is one of the key modifiable risk factors for hyperglycemia. Evidence from population-based crosssectional studies indicates that both physical activity and sedentary behavior (particularly television viewing time) are independently associated with blood glucose in adults without known diabetes (6 -8). However, the physical activity and sedentary time variables in these studies have typically been derived from se...

Longer Time Spent in Light Physical Activity Is Associated With Reduced Arterial Stiffness in Older Adults

“…Several recent studies indicated that objective measured light-intensity PA is beneficially associated with blood glucose and other metabolic risk factors. 18,[25][26][27] Taken together, these findings suggested that the favorable effect of light PA on arterial stiffness is mediated by metabolic profile improvement. Other mechanisms by which daily light PA may influence arterial stiffness in older people are still speculative and include the effects of PA on the bioavailability of NO, vascular smooth muscle tone, connective tissue cross-linking, and gene expression.…”

“…15,16 Objective evidence has been reported indicating that light PA has a relatively high energy cost during daily living 13,17 and is beneficially associated with traditional risk factors. 18 Therefore, we hypothesized that the longer time spent in light PA assessed by triaxial accelerometry may be associated with reduced arterial stiffening. Moreover, it is also unclear whether the effects of light PA are the same in fit and unfit individuals.…”

Sedentary time, breaks in sedentary time and metabolic variables in people with newly diagnosed type 2 diabetes

“…Few other studies have looked at insulin levels to help clarify these observations. An association between sedentary time and 2 h plasma glucose has been reported [28], but in contrast to results from healthy adults, no association was found between sedentary time and insulin resistance in adults with a family history of diabetes [22].…”

Prevalence and Correlates of Exergaming in Youth

“…16,17 Because exergames can be played in a variety of settings including unsafe neighborhoods, 18 they can increase opportunities for youth to engage in PA 11,12,16,19,20 and decrease sedentary behavior. 18,19,[21][22][23][24][25] Exergaming may have added value in youth compared with adults because young people are generally more physically active (ie, move more) while exergaming, 26 and game exertion (effort) is not a deterrent to exergaming. 27 Exergaming may be more enjoyable than sedentary video games and treadmill workouts, 28 and they provide youth with opportunities to try a range of sports (eg, boxing, kung fu), which may in turn increase motivation to become involved in these activities at school or local sports centers.…”