Systematic review of gender differences in the epidemiology and risk factors of exertional heat illness and heat tolerance in the armed forces

BMJ Open. 2020 Apr 6;10(4):e031825. doi: 10.1136/bmjopen-2019-031825.


Objectives: This review aimed to describe the epidemiology of all heat-related illnesses in women compared with men in the armed forces and to identify gender-specific risk factors and differences in heat tolerance.

Design: A systematic review of multiple databases (MEDLINE, Emcare, CINAHL, PsycINFO, Informit and Scopus) was conducted from the inception of the databases to 1 April 2019 using the preferred reporting items for systematic review and meta-analysis guidelines.

Eligibility criteria: All relevant studies investigating and comparing heat illness and heat tolerance in women and men in the armed forces were included in the review.

Results: Twenty-four studies were included in the systematic review. The incidence of heat stroke in women ranged from 0.10 to 0.26 per 1000 person-years, while the incidence of heat stroke ranged from 0.22 to 0.48 per 1000 person-years in men. The incidence of other heat illnesses in women compared with men ranged from 1.30 to 2.89 per 1000 person-years versus 0.98 to 1.98 per 1000 person-years. The limited evidence suggests that women had a greater risk of exertional heat illness compared with men. Other gender-specific risk factors were slower run times and body mass index. Although there was a higher proportion of women who were heat intolerant compared with men, this finding needs to be interpreted with caution due to the limited evidence.

Conclusion: The findings of this review suggest that men experienced a slightly higher incidence of heat stroke than women in the armed forces. In addition, the limited available evidence suggests that a higher proportion of women were heat intolerant and being a female was associated with a greater risk of exertional heat illnesses. Given the limited evidence available, further research is required to investigate the influence of gender differences on heat intolerance and heat illness.

Keywords: accident & emergency medicine; armed forces; heat stroke; occupational & industrial medicine; women.

Publication types

  • Research Support, Non-U.S. Gov't
  • Systematic Review

MeSH terms

  • Female
  • Heat Stress Disorders / epidemiology
  • Heat Stroke / epidemiology*
  • Heat Stroke / etiology
  • Heat Stroke / physiopathology
  • Humans
  • Incidence
  • Male
  • Military Personnel / statistics & numerical data*
  • Risk Factors
  • Sex Distribution
  • Sex Factors*
  • Thermotolerance / physiology*