The Impact of Removal of Exercise for 3 Days on Glycemic Control in Older Active Adults

Abstract

Postprandial glycemia (PPG) predicts cardiovascular disease, and 3 days of physical inactivity impairs PPG in young, active adults. Whether this occurs in older, active adults who may be more prone to bouts of inactivity is unknown. This study determined if PPG was impaired in active older adults (old) following a 3 day removal of exercise compared to active young adults. In this randomized, crossover study, 10 older (73.0 ± 1.9 yrs) and 9 young (32.8 ± 1.8 yrs) habitually active (≥90 min/week of exercise) adults completed a 3 day period of exercise removal (NOEX) and a 3 day period of normal exercise maintenance (EX), separated by ≥ 1 week. Diet was standardized across phases. Glycemic control (GC) (2 hour PPG, peak glucose values, and standard deviation (STDEV) of blood glucose values) was assessed via continuous glucose monitoring (IPro2, Enlite Sensors, Medtronic Inc., Northridge, CA) during both phases. No differences in body mass index (Old: 26.5 ± 1.3, Young: 24.8 ± 1.0 kg/m2, p>0.05) existed between groups. Both groups had a similar reduction in activity during NOEX (Old: ‐64.6% ± 6.2, Young: ‐55.7% ± 4.9, p>0.05). There were significant main effects (p<0.05) in PPG of age (Old: 116±1.2 mg/dL, Young: 106 ± 1.3 mg/dL), phase (Inactive: 113 ± 1.3 mg/dL, Active: 109 ± 1.2 mg/dL), and time (0 min: 99 ± 2.0, 30 min: 118 ± 2.0, 60 min: 117 ± 2.0, 90 min: 112 ± 2.0, 120 min: 108 ± 2.0 mg/dL), but no interaction (p>0.05). Further, a trend (p=0.06) for significant main effect of age (Old: 149±5.6, Young: 133±5.9 mg/dL) and phase (p<0.05; Inactive: 145±4.4, Active: 136±4.4 mg/dL) were found for peak glucose values. Significant main effects (p<0.05) exist for age (Old: 15.3±1.2, Young: 11.3±1.2) and phase (Inactive: 14.4±0.97, Active: 12.2±0.97) for blood glucose STDEV. These results indicate that older adults have impaired GC compared to young adults and that removal of exercise impairs GC. Yet, the impairment in GC with exercise removal is not different between old and young adults when the decrease in daily physical activity is similar.