Cardiorespiratory responses of load carriage in female and male soldiers

Purpose: To investigate the effect of sex and load carriage on cardiorespiratory responses to high intensity exercise in male and female soldiers.& nbsp;Methods: Soldiers (9 women, 9 men) performed a graded treadmill test until exhaustion with no load (NL) and combat-gear with body armor (CG). Cohen's d effect sizes, paired t-tests and ANOVA were used to study differences between conditions. A mixed linear regression model analyzed the relationship between heart rate (HR) and oxygen uptake (VO2) with load and between sexes.& nbsp;Results: Wearing CG resulted in, for both sexes, a decreased time to exhaustion (-11 min), lower VO2peak (L/min) ES = 0.56; VO2peak (mL//kg/min) ES = 2.44, both p < 0.001, a net decrease in minute ventilation (ES = 3.53) and no change in HRmax. No sex-difference were present except for absolute VO2peak. The VO2 and HR relationship showed a cardiorespiratory reduction wearing CG vs. NL. Added load was equal between sexes, although female soldiers' CG relative to body mass was higher (25%) than male soldiers' (20%), p < 0.01.& nbsp;Conclusion: Wearing CG reduces soldiers' cardiorespiratory capacity and exercise performance level, although the reduction cannot be explained solely based on the added load of CG, instead CG seems to restrict the capacity to fully ventilate. No sex differences were found in relative cardiorespiratory responses to wearing CG compared to NL.

Automated summary

This study aimed to investigate the effects of sex and load carriage on cardiorespiratory responses to high intensity exercise in male and female soldiers. The results showed that wearing combat-gear with body armor reduced soldiers' cardiorespiratory capacity and exercise performance level, with no differences between sexes. The added load was similar between sexes, but female soldiers had a higher load relative to body mass. Therefore, wearing combat-gear with body armor seems to restrict the soldiers' ability to fully ventilate.