Relationship between Ambulatory Activity and Insulin Sensitivity in Older Adults

Abstract

PURPOSE: To investigate the relationships between accumulated physical activity (PA), estimated insulin sensitivity (IS), total body fat percentage (BF), and waist circumference (WC) in an older adult population. METHODS: Thirty four older adults (9 males, 25 females; 65.6 ± 6.8 y; BF 40.5 ± 8.5 %; WC 95.4 ± 10.3 cm) participated in this cross-sectional study. Height, body mass, and WC were measured. BF was assessed via dual energy x-ray absorptiometry. Fasting venous glucose and insulin were measured. IS was calculated according to the Quantitative Insulin Sensitivity Check Index (QUICKI) method. Participants wore a pedometer (Yamax SW-200) for seven consecutive days during all waking hours. Average steps/d were calculated. Correlation analyses were performed to examine relationships between QUICKI scores, steps/d, BF, and WC. Participants were dichotomized into low or high activity groups based on median steps/d (<4917steps/d, ≥4918 steps/d). Independent samples t-tests were performed to examine differences in IS, BF, and WC across the low and high activity groups. RESULTS: Mean IS for the group was 0.3725 ± 0.0316. Average steps/d were 5251 ± 2000. IS was positively correlated with BF (r= .425, p=.014) and WC (r=.392, p=.022), however, there was no significant relationship between IS and steps/d (r= .031, p=.861). Despite significant differences in step/d between the low and high activity groups (3689 ± 214 vs. 6813 ± 367 steps/d, respectively; p=.042), no significant differences were noted in QUICKI (p=.778), BF (p=.866), or WC (p=.081) between these groups. CONCLUSIONS: The current study indicates that IS is related to estimates of obesity, but not PA, in this older adult population. This suggests that level of adiposity may be more important to IS than accumulated PA in this group of older adults. Future research exploring the relationship between intensity of PA and IS in older adults is warranted.