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

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 3 hours per day in LPA, further increase their LPA, they could see benefit to glucose control.