Sex differences in the physiological response to a demanding military field exercise

Abstract

Purpose To investigate sex differences in the effect of a military field exercise on physical performance, body composition, and blood biomarkers. Methods Measurements were done in 23 male and 12 female conscripts before, and 0, 1, 3, 7, and 14 days after a 6‐day military field exercise. Results During the field exercise, body mass decreased more in men (−6.5 ± 1.1 kg) than in women (−2.7 ± 0.7 kg), and muscle mass decreased only in men (−2.7 ± 1.0 kg). Body composition recovered within one week. Performance decreased, with no differences between men and women for countermovement jump (CMJ,‐19 ± 8 vs. −18 ± 11%), medicine ball throw (MBT, −11 ± 7 vs. −11 ± 7%), and an anaerobic performance test (EVAC, −55 ± 22 vs. −47 ± 31%, men and women, respectively). MBT and EVAC performance recovered within two weeks, whereas CMJ performance was still reduced in men (−17 ± 6%) and women (−9 ± 8%) after two weeks recovery, with a larger reduction in men. Both men and women decreased [IGF‐1] (−28 ± 9 vs. −41 ± 8%) and increased [cortisol] (26 ± 26 vs. 66 ± 93%, men and women, respectively) during the exercise. Most biomarkers returned to baseline values within one week. Conclusions Men lost more body mass and muscle mass than women during a field exercise, but these differences did not lead to sex differences in changes in explosive strength and anaerobic performance. However, women recovered explosive strength in the legs faster than men.

Factors Influencing the Executive Functions of Male and Female Cadets

“…In contrast, in a study by Vikmoen et al carried out during initial fitness measurements before demanding selection exercises, as in our study, women had a significantly lower weight and muscle mass compared to men, while men were characterized by lower levels of fat tissue compared to women. In the above studies, men also performed significantly better in tests such as the countermovement jump, evacuation test, and medicine ball throw [ 24 ]. It should be noted that these were different tests than those used in our study, but they certainly provide great comparative value.…”

“…In regard to these increasing expectations, research is continuing on gender differences among soldiers across different levels. Research has highlighted differences in endurance, efficiency, and muscular fitness between male and female soldiers [ 23 ]; as a result of which, women are exposed to greater physiological stress during similar military activities [ 24 ]. Differences in PF between men and women are the subject of research among both cadets [ 25 ] and operational troops [ 23 ], and research has also focused on gender-specific adaptation to military training [ 26 ].…”

Feeding female soldiers: Consideration of sex-specific nutrition recommendations to optimise the health and performance of military personnel

“…High total daily energy expenditures (TDEE) and / or energy deficits are commonly reported during military training courses. [1][2][3][4][5][6] Energy deficit is associated with negative whole-body protein balance, 7,8 decreased lean body mass 3,9 and muscle performance, 3,[9][10][11][12][13] impaired endocrine function, 3,4,9,14 uncoupled bone turnover 15,16 and a loss of bone mass. 4,16 Appropriate nutritional strategies are important for military personnel to prevent maladaptive effects of high TDEE on health and performance, and to promote muscle, bone and physical performance adaptations to high volumes of exercise.…”

“…17,18 Although men and women must complete identical military tasks in the UK and US Armed Forces, women have lower TDEE but higher physiological strain, 20,21 and a twoto three-fold higher risk of musculoskeletal injury [22][23][24] and stress fracture, 25 compared with men in military training. Women may also be more susceptible to the maladaptive effects of military training in energy deficit on endocrine 12 and reproductive function. 26 Lower TDEE in women may, however, confer an advantage by attenuating energy deficits and lean mass losses compared with men.…”

“…26 Lower TDEE in women may, however, confer an advantage by attenuating energy deficits and lean mass losses compared with men. 12,27 Women across many nations are now allowed to operate in arduous ground close combat roles, which demand high levels of physical fitness to meet the physical employment standards for their role.…”