Blood Pressure Response during Combined Inspiratory Loading and Subsytolic Circulatory Occlusion during Exercise: Effects of Sex and Menstrual Cycle

Abstract

Locomotor and respiratory muscle feedback via group III/IV afferents influences the blood pressure response during exercise. Specifically, stimulation of the inspiratory and locomotor muscle afferents (via inspiratory loading (IL) and subsystolic circulatory occlusion (CUFF), respectively) increases the blood pressure response during exercise with combined IL and CUFF (IL+CUFF) further augmenting the blood pressure response. Sex differences in blood pressure have been observed in both IL and CUFF when investigated individually, while the influence of sex hormones is unclear. It is unknown if sex and menstrual cycle phase influences the blood pressure response to IL+CUFF during exercise.PurposeTo determine if sex and menstrual cycle phase influence the blood pressure response during IL+CUFF in men and premenopausal women. We hypothesized that women will exhibit attenuated increases in blood pressure compared to age‐matched men during IL, CUFF, and IL+CUFF, while no differences would be present across the menstrual cycle.MethodsTo date, 13 adults (7M/6W; M: 28±6 vs. W: 29±4 yrs, p=0.30; M: 27±5 vs. W: 25±2 kg/m2, p=0.85) have participated in this study. Participants performed four 10 min exercise bouts at 40% of their peak oxygen uptake. The participants performed spontaneously breathing (SB) during the first 5 minutes and voluntary hyperventilation (i.e. breathing frequency of 40 breaths/min with 50% duty cycle) during the last 5 minutes. During this last 5 min, IL (30% maximal inspiratory pressure), CUFF (80 mmHg), IL + CUFF, or no intervention (CTL) occurred in a randomized order. Women completed the study protocol twice, once during midluteal (ML) phase and once during early follicular (EF) phase. Blood pressure was measured using manual sphygmomanometry. Changes in systolic blood pressure (ΔSBP), diastolic blood pressure (ΔDBP), and mean arterial pressure (ΔMAP) were determined by subtracting values obtained during IL, CUFF, IL+CUFF, or CTL from SB.ResultsThere were no significant differences in ΔMAP across groups during CTL (M: 5±5; ML 2±2; EF: 2±2 mmHg, all p>0.24), IL (M: 11±4; ML 10±2; EF 12±5 mmHg, all p>0.60), CUFF (M: 19±6; ML 16±4; EF 20±2 mmHg, all p>0.20), or IL + CUFF (M: 24±5; ML 23±6; EF 23±3 mmHg, all p>0.82). There were no significant differences in ΔSBP across groups during CTL (M: 5±4; ML 5±4; EF: 8±13 mmHg, all p>0.49), IL (M: 17±6; ML 17±5; EF 19±8 mmHg, all p>0.63), CUFF (M: 24±12; ML 23±7; EF 28±5 mmHg, all p>0.31), or IL + CUFF (M: 34±8; ML 33±11; EF 33±8 mmHg, all p>0.94). There were no significant differences in ΔDBP across group during CTL (M: 5±8; ML 0±1; EF: −1±4 mmHg, all p>0.05), IL (M: 8±3; ML 7±2; EF 9±4 mmHg, all p>0.71), CUFF (M: 16±4; ML 13±4; EF 16±2 mmHg, all p>0.20), or IL + CUFF (M: 19±6; ML 18±6; EF 18±3 mmHg, all p>0.75).ConclusionWith this limited sample size, our data suggest that neither sex nor menstrual cycle phase influences the blood pressure response with IL, CUFF or IL+CUFF.Support or Funding InformationNIH HL126638AHA 18POST3990251This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.