In recent decades, there has been a greater focus on the cardiovascular benefits of regular exercise. One such benefit is improved cardiorespiratory fitness. A review published in the British Journal of Sports Medicine examined the question of whether sex differences exist in cardiorespiratory fitness and all-cause mortality.
This article reads like a research paper, structured around summarizing findings and implications; it will not be an accessible or engaging read for blog audiences. Given our audience’s interest in topics related to gender and psychology, we recommend approaching this topic with more opinionated writing that prompts readers to think critically about their own beliefs.
Why do males tend to have better cardiorespiratory fitness than females? Many theories exist, but differences in circulating hormones have been ruled out as a cause. The question then becomes what accounts for this difference in fitness between males and females? Genetics is likely to play a role; it has been found that most of the sex difference in cardiorespiratory fitness is genetic rather than environmental. This means that it will be difficult to change the sex difference in cardiorespiratory fitness through environmentally-based interventions, even if such interventions were effective with children or adults.
Sex Differences in Cardiorespiratory Fitness and All-Cause Mortality :
1. Sex Differences in Cardiorespiratory Fitness
Studies have found that males have better cardiorespiratory fitness than females. This means that males tend to be able to run longer distances at a given speed and/or consume more oxygen during exercise than females. Children who did not experience either of these symptoms continued until the end of the treadmill.
The results showed that girls quit running sooner than boys on average. Although there was no sex difference in the rate of heart rate or oxygen consumption during walking, there was a significant difference between boys and girls as to how many miles (or kilometers) each child was able to run before reaching their limit.
2. Sex Differences in All-Cause Mortality
In addition to differences in cardiorespiratory fitness, studies have found that males tend to have lower all-cause mortality than females. A study by Ewen et al. aimed to examine the correlation between sex differences in all-cause mortality and cardiorespiratory fitness. Participants in this study were 16,550 male and female British civilians aged between 40 and 79 years.
A systematic review of the literature was performed on all-cause mortality rates according to fitness levels, with a focus on sex differences. All-cause mortality rates for males and females with low cardiorespiratory fitness (< 8 METs) were compared with all-cause mortality rates for males and females with high cardiorespiratory fitness (> 8 METs). When the difference in absolute risk (death rate) between the two groups was greatest, there was also a greater difference in mortality rate.
3. Sex Differences in Cardiorespiratory Fitness and All-Cause Mortality:
Explanations: Genetic and environmental factors may explain the sex difference in cardiorespiratory fitness. Hormones may play a part. The researchers of this review mention that because the majority of sex differences in cardiorespiratory fitness are genetic rather than environmental, it will be difficult to change them through environmentally-based interventions, even if these interventions are effective with children or adults. However, it is possible that hormones can have an effect on cardiorespiratory fitness even after puberty as data shows some male-female differences continue into adulthood .
Implications:
The results of the review mean that gender differences in cardiorespiratory fitness exist early on, even among children who are relatively fit. Given the fact that differences in fitness lead to differences in all-cause mortality, it is important to consider these findings when planning exercise programs.
For example, if possible it may be more beneficial to include more moderate exercises in an exercise program geared towards females, as they may have difficulty completing high intensity exercises. The authors also suggest that future research should focus on providing additional details about the relationship between sex and cardiorespiratory fitness levels and all-cause mortality at different ages.
It is important to consider genetic as well as environmental factors in fitness and all-cause mortality, because this information could help with future policies that focus on preventing disease. This review has helped to provide more evidence in support of the theory that sex differences in cardiorespiratory fitness are different because of genetics; it also highlights the importance of providing programs tailored to children’s needs and abilities.
Impact on Policy Making:
Researchers have found that many populations, such as adolescents, adults, and the elderly, do not consume enough calories. Because of this dietary deficiency, they are at risk of cardiovascular illness; this is why it would be beneficial to provide more exercise to give these people this exercise requirement that is needed for cardiorespiratory fitness.
This is one way that policies can indirectly affect population health. For example, programs or initiatives should be created that encourage people to exercise more frequently or at a moderate intensity level. This may increase heart activity during activity and therefore lead to better cardiorespiratory fitness levels.
