Hemodynamic Responses and the Sustainability of Force during Submaximal Isometric Handgrip Exercise: Are There Sex Differences?

Abstract

Background: Sex related differences in the control of blood pressure at resting conditions have been previously reported. Studies in rodents have also shown that during exercise, female animals have an enhanced capacity to inhibit sympathetic vasoconstriction than male animals. Aims: To examine whether sex differences exist in (i) systolic/diastolic blood pressure (SBP/DBP) and systemic vascular resistance (SVR) responses during handgrip exercise, (ii) the ability to sustain a predetermined target force during isometric handgrip, in young, healthy, lean adults. Study Design / Methodology: Fourty-six adults (19 men and 27 women), aged 20-27 years, underwent a protocol that included a seated rest (baseline), a 3-min handgrip at 30% of maximal voluntary contraction (MVC), and recovery. Continuous, beat-to-beat SBP/DBP and heart rate were recorded (Finapres). Handgrip force was monitored (Biopac). Results: Men had higher MVC than women (P < 0.001), however, both sexes exhibited similar handgrip steadiness. Men rated the exercise session as fatiguing as their female counterparts. During baseline, no differences were found between groups in SBP, DBP, and heart rate; however, during exercise and recovery, men exhibited a higher DBP response than females (P < 0.05). SVR remained relatively stable during handgrip in men, whereas, a decline in SVR during exercise and recovery was observed in women (P < 0.05). Conclusion: Differential hemodynamic responses during isometric exercise and recovery were revealed between young, healthy, and lean men and women. However, the steadiness and ability to sustain force during isometric exercise were not significantly different between men and women.