Inspiratory Muscle Function Is Linked To Aerobic Capacity And Sedentary Bouts In Late Postmenopausal Women

Aerobic capacity and physical activity are modifiable factors associated with disability risk in late postmenopausal women. However, the interaction between inspiratory muscle function and these parameters remains unclear in this population. PURPOSE: To examine the relationship between indices of inspiratory muscle function, walking economy, estimated V̇O2peak, and free-living physical activity in late postmenopausal women with overweight/obesity. METHODS: Following familiarization, 11 late postmenopausal women (64 ± 8 y; body mass index = 30.8 ± 4.4 kg/m2) completed tests of inspiratory muscle strength and endurance using a flow-resistive inspiratory muscle trainer. Participants performed two walking protocols: 1) a 6-min, fixed-workload (0.89 m/s at 0% grade) treadmill task coupled with indirect calorimetry to measure walking economy (steady-state net V̇O2) and 2) a standardized 6-minute walk test performed on an indoor track to estimate V̇O2peak. Free-living physical activity was measured during waking hours over 7 consecutive days via accelerometry. Pearson correlations coefficients were used to assess relationships of interest. RESULTS: Maximal inspiratory pressure significantly correlated with walking economy (r = 0.760, p = 0.007). Maximal inspiratory muscle power output significantly correlated with estimated V̇O2peak (r = 0.629, p = 0.038). Inspiratory time significantly correlated with age (r = -0.838, p = 0.001) and duration of sedentary bouts (r = -0.881, p < 0.001) but not walking economy (r = -0.527, p = 0.096) or estimated V̇O2peak (r = 0.525, p = 0.097). CONCLUSIONS: Inspiratory muscle function is correlated with walking economy, estimated V̇O2peak, and duration of sedentary bouts in late postmenopausal women with overweight/obesity. Considering the potential impact on mobility independence and disability risk, targeted interventions to augment inspiratory muscle function warrant consideration. Supported by: Supported by the Indiana Clinical and Translational Sciences Institute funded in part by grant number UL1TR002529 from the NIH-NCATS.