Duration-Response of Light-Intensity Physical Activity and Glucose Dynamics in Older Adults.

Abstract

Older adults spend 30% of their day in light-intensity physical activity (LPA). This study was designed to determine if increasing the proportion of time spent in LPA would affect glucose control. Older adults (N = 9) completed four 3-hour treatment conditions consisting of a seated control and 3 randomized conditions: (1)20% time spent in continuous LPA, 80% seated; (2)40% time spent in continuous LPA, 60% seated; and (3)60% time spent in continuous LPA, 40% seated. Energy expenditure was measured continuously, and glucose was measured prior to mixed-meal ingestion and hourly thereafter. Glucose area under the curve was compared between conditions using Friedman test. There was a significant difference in glucose area under the curve by time spent in LPA (P < .001); specifically, between the seated and 60% LPA (mean difference = 35.0 [24.6]mg/dL, P = .01), seated and 40% LPA (mean difference = 25.2 [11.8]mg/dL, P = .03), seated and 20% LPA (mean difference = 17.8 [22.5]mg/dL, P = .03), 20% LPA and 60% LPA (mean difference = 17.2 [22.5]mg/dL, P = .01), and 40% LPA and 60% LPA (mean difference = 9.8 [7.3]mg/dL, P = .01). These results provide experimental evidence to the importance LPA has on metabolic health. If older adults who already spend, on average, about 3hours per day in LPA, further increase their LPA, they could see benefit to glucose control.