Heart Rate Responses During Bodyweight Exercise And Walking In Women With Or At-risk For Diabetes

Previous studies have used high-intensity interval exercise as a strategy to improve metabolic health. However, most studies have taken place in the lab and the feasibility of home-based unsupervised intervals is not widely characterized. PURPOSE: To characterize the self-selected exercise intensity of walking compared to low-volume bodyweight interval exercise (BWI) using heart rate responses under free-living conditions in women aged 50+ with or at risk for type 2 diabetes. METHODS: 52 women (age: 60 ± 6 yr, BMI: 31 ± 7 kg/m2) with (pre)diabetes or a moderate to high Canadian Diabetes Risk score (≥21 points) participated remotely across Ontario, Canada. In a randomized and counterbalanced order, participants performed a video-based 8 x 1-min BWI protocol (1-min rest, 15 min total) or a 30-min walk (WALK) 30 min following dinner on two separate days. Both exercise sessions were completed under free-living conditions without supervision. Participants were instructed to walk at a moderate pace for WALK and complete as many repetitions as possible during the BWI exercise intervals. A wrist worn physical activity monitor was used to measure HR during exercise. Exercise intensity in each session was characterized by percentage of heart rate reserve (%HRR). Mean and peak %HRR were calculated for BWI and WALK. Participants were stratified into two groups based on whether a higher mean %HRR was achieved in BWI or WALK. Between group differences in medical diagnoses that may present as a barrier to performing exercise (arthritis, osteoporosis, joint replacement, metabolic disease status) were examined. RESULTS: All sessions were completed without adverse events. Mean %HRR (59 ± 13 vs. 54 ± 11, p = 0.017) and peak %HRR (88 ± 14 vs. 75 ± 16, p = <0.0001) were higher in BWI vs. WALK. Participants whose self-selected intensity was lower in BWI vs WALK (n = 16, 30.8%) had a higher combined prevalence of arthritis, osteoporosis or joint replacement compared to participants who performed BWI at a higher exercise intensity (62.5% vs 30.4%, p = 0.005). CONCLUSIONS: Women with or at risk for diabetes can safely and effectively complete BWI at home. Arthritis, osteoporosis, and joint replacement may present a barrier to achieving a higher intensity with BWI.Supported by CCS and CIHR