Activity Energy Expenditure, Sedentary Time, And Cardiometabolic Responses To An Exercise Intervention: The PAACE Study

Abstract

Sedentary time (ST) and physical activity energy expenditure (PAEE) are associated with obesity and related comorbidities, especially among older men and women. Older African Americans (AA) may have lower PAEE, higher ST, and greater cardiometabolic health disparities than other racial/ethnic groups. Thus assessing effects of physical activity interventions that improve PAEE and ST on cardiometabolic risk factors (CMRF) within this group is important. PURPOSE: To evaluate the association between physical activity intervention associated PAEE and ST changes and CMRF responses to the intervention among older AA. METHODS: Fifty-six sedentary older (mean ± SD, 69.2 ± 3.4 years) AA were randomized to a physical activity group (PAG, n = 28) or successful aging group (SAG, n = 28) for 12 weeks. PAG participants attended twice-weekly physical activity group sessions at a local YMCA. In addition, the PAG participants exercised 2-3 days per week at home for a total of 150 minutes of MVPA per week. The SAG participants attended weekly educational sessions on general aging topics not related to physical activity. Accelerometers worn on the waist before and during the last week of intervention were used to calculate PAEE and ST using 60-second epoch. Body mass index, fasted glucose (GLU), high density lipoprotein (HDL), low density lipoprotein (LDL), triglycerides, and blood pressure were collected before and after the intervention to assess cardiometabolic risk. Linear regression was used to test the association between PAEE and ST changes and CMRF. RESULTS: PAEE and ST change were not different between PAG and SAG participants (PAEE: 45.5 ± 149.1 vs. 10.9 ± 79.5 kcal/d resp., p = 0.298; ST: 41.6 ± 149.6 vs. -10.6 ± 122.9 min/d resp., p = 0.169). Baseline CMRF were not different between PAG and SAG participants (all p > 0.05). Change in PAEE was not associated with change in any CMRF within PAG participants (all p > 0.161). A decrease in ST was associated with an increase in HDL (F[1, 26] = 7.380, p = 0.012, R2 = 0.221) and a marginally significant decrease in GLU (F[1, 26] = 3.162, p = 0.087, R2 = 0.108) within PAG participants. CMRF changes were not related to PAEE change (all p > 0.159) or ST change (all p > 0.123) for SAG. CONCLUSIONS: The PAG may not have received sufficient stimulus to improve PAEE and ST, thus preventing more robust changes in CMRF.