Blood Pressure Response During Hyperpnoea Is Lower in Women Compared with Men

Abstract

It has been reported that women exhibit less inspiratory muscle fatigue during exercise. Additionally, a recent study found a lower blood pressure response to resistive inspiratory muscle activity (high-resistance, low-speed inspiratory muscle contractions), indicating that women exhibit an attenuated inspiratory muscle metaboreflex compared to men. Another way to model the respiratory muscle metaboreflex is to measure the cardiovascular response to exercise-mimicking hyperpnoea (low-resistance, high-speed inspiratory and expiratory muscle contractions). It is hypothesized that women will have a lower cardiovascular response to low-resistance, high-speed inspiratory and expiratory muscle contractions. PURPOSE: To test this hypothesis, the cardiovascular response during voluntary normocapnic incremental hyperpnoea was evaluated in young women and age-matched men. METHODS: Healthy young subjects (8 men, 10 women) participated in this study. An incremental respiratory endurance test was performed as follows: target minute ventilation was initially set at 30% of maximal voluntary ventilation (MVV12) and was increased by 10% MVV12 every 3 min. The test was terminated when the subject could no longer maintain the target ventilation. Heart rate and arterial blood pressure (BP) were continuously measured. RESULTS: There was no significant difference in respiratory endurance time between women (11.6±0.6 min) and men (12.3±0.5 min). The change in mean arterial BP (MBP) during the incremental respiratory endurance test was significantly lower in women compared to men (women: 105.9±3.2 mmHg, men: 126.0±6.0 mmHg at 9 min). CONCLUSIONS: The data from the present study suggests that the respiratory muscle-induced metaboreflex is blunted in women compared to age-matched men.