Miller, Sophie

Introduction: An elevated blood pressure (mean arterial pressure, MAP) response to exercise is an independent predictor of hypertension (HTN) development. HTN is highly prevalent in postmenopausal females. Postmenopausal, compared to premenopausal, females have a higher MAP at rest and during exercise primarily due to higher systemic vascular resistance (SVR). Studies using small muscle mass exercise have suggested that postmenopausal females have augmented increases in MAP from rest to exercise. However, it is unclear if postmenopausal females have augmented MAP responses from rest to exercise during whole-body exercise. Hypothesis: We hypothesized that postmenopausal females would have greater increases in MAP and smaller decreases in SVR from rest to peak exercise than premenopausal females. Methods: Normotensive premenopausal (n=16; age: 30±7 yrs; BMI: 23±4 kg/m 2 ) and postmenopausal (n=14; age: 57±7 yrs; BMI: 27±4 kg/m 2 ) female participants performed an incremental cycling test until task failure. Blood pressure was measured by manual sphygmomanometry, cardiac output (Q) via open-circuit acetylene wash-in technique, and SVR was calculated. Data are reported at rest and peak oxygen uptake (VO 2 ). Data are also reported as % change from rest to VO 2 peak. Results: Postmenopausal females had higher MAP and SVR at rest and at VO 2 peak than premenopausal females (all, p<0.05). Postmenopausal, compared to premenopausal, females had lower Q at VO 2 peak commensurate with the lower achieved VO 2 peak (p<0.01). Resting MAP was positively related to MAP at VO 2 peak in postmenopausal females (r=0.85, p<0.01), but not premenopausal females (p=0.22). % change in MAP from rest to VO 2 peak was not different between groups (Post: 18±8 vs. Pre: 18±9%) (p=0.94). However, postmenopausal females had smaller % decreases in SVR from rest to VO 2 peak (Post: -44±7 vs. Pre: -54±8%) and smaller % increases in Q compared to premenopausal females (Post: 113±31 vs. Pre: 162±50%) (both, p<0.01). Conclusion: Our findings indicate that postmenopausal and premenopausal females have similar increases in MAP from rest to VO 2 peak; however, the mechanisms contributing to the MAP response differed by menopausal status. Postmenopausal females relied on smaller decreases in SVR, whereas premenopausal females had greater increases in Q. These findings provide important insight into the mechanisms contributing to the clinically relevant higher MAP response during exercise in postmenopausal females.

Background: Cardiac rehabilitation (CR) patients demonstrate a high burden of chronic conditions (CC). Both multimorbidity (MM; ≥2 coexisting CC) and aging negatively impact functional capacity, whereas CR improves performance. Age-related difference in cardiorespiratory fitness (CRF, peak oxygen uptake (VO 2 )) in CR patients with MM has not been studied. Hypothesis: We hypothesized improvement in CRF will be attenuated by MM with increasing age in CR patients. Aims: We aimed to identify age-related differences in CRF improvement in CR patients with MM. Methods: Patients ≥18 yrs old who attended ≥1 CR sessions from 1999-2017 and completed cardiopulmonary exercise stress test before and after CR were included. The prevalence of CC was assessed using Rochester Epidemiology Project records-linkage system. Age categories included: Younger (18-49 yrs), Midlife (50-64 yrs) and Older (≥65 yrs). CRF categories included: <0%, 0-8% and >8%. Analysis included Kruskal-Wallis and Chi-squared. Results: Of 622 patients, 75.4% were male. Mean age: 62.9±11.2 yrs; Younger (n=70) age: 42.7±6.8 yrs, 67.1% male; Midlife (n=283) age: 58.3±4.3 yrs, 78.8% male; Older (n=269) age: 73.0±5.2 yrs, 74.0% male. BMI was 29.9±5.4 kg/m 2 (Younger: 30.0±6.7, Midlife: 30.4±5.6, Older: 29.3±4.7; p<.05). Median (Q1, Q3) no. of CR sessions attended was 33(22, 35), with lower attendance in the Younger group: 25(16,34) vs Midlife: 33(20,35) and Older: 34 (29,35), p<.05. Overall, percent change in peak VO 2 was 11.5±21.6% (Younger: 18.8±22.8%, Midlife: 11.6±19.5%, Older: 9.4±23.1%; p<.01). The median number of CC was 7(5,8) with significant differences across groups: Younger: 5(3,7), Midlife: 6(5,8), Older: 7(6,9), p<.01. Number of CC increased with age across all CRF categories (p<.01, Fig. 1). However, there was no difference in number of CC within age groups across categories of CRF, Table 1. Conclusions: Our results suggest that MM increases with age in patients attending CR; however, within a given age group, improvement in CRF does not appear dependent on MM. The impact of age appears to have a greater impact than MM on CRF improvement. Individualized treatment plans should focus on the impact of age-related disparities on CRF improvement among CR patients with MM.