The impact of exercise on the female cardiovascular system, in general terms, is identical in many respects to the relationship between male physical activity and cardiovascular health. It is when the specifics of various training aspects are considered in relation to the female structure that gender distinctions arise. Men and woman have identical heart, lung, and circulatory structures in terms of how the organs and blood system function in relation to one another and to the related human systems; male and female bodies respond similarly to the stresses of athletic activity upon crucial processes such as the central nervous system and the musculoskeletal system. Male and female athletes exhibit similar responses to the different types of energy requirements imposed on the body by various sports; the thresholds for the
Cardiovascular health is as important a consideration for women of every age as it is for men. Cardiovascular disease kills more women yearly in North America than all forms of cancer combined. Further, there is now considerable research data to confirm that women may have a slightly higher risk of myocardial infraction (heart attack) after menopause than men in the same age group (over 50 years of age) due to generally lower levels of the female hormone estrogen being present in the body. A similar examination of female exercise patterns in the postmenopausal population suggests that increased exercise for these persons will lead to a lessened risk of heart attack, arteriosclerosis (the thickening of the arteries), and a generally improved blood flow.
The specific considerations of postmenopausal females aside, the physical gender differences between the relative exercise performance capabilities of men and women are ones of scale, not type. It is important to note that there is no overlying social consideration or sexism in the assessment of the training capacities of women versus men; these factors are physiological, rooted in the genetic development of the male and female bodies. These physical differences undoubtedly impact how women should train their cardiovascular capability.
It is the relative size of the female heart, lungs, and available blood volume that govern the function and the maximum limits of both the cardiovascular and cardiorespiratory systems. Organ size is roughly proportionate to overall body size. For this reason, men will generally possess a larger heart, lungs, and greater blood volume than women. The heart muscle in a male will be larger and stronger, with a greater ability to propel blood more quickly and efficiently, than the female organ. A greater blood volume will result in a larger oxygen transport capacity, and a resulting superior energy burning with which to fuel muscular activity. In general terms, these larger organs and supporting systems create in a male of similar general fitness to that of a female a greater ability to consume and process oxygen, known as the VO2max. The VO2max is essential to extending the limit of an athlete's physical best performance; it will tend to be a capacity that is approximately 10% greater for the male than the female athlete, a statistic supported through observations across a broad spectrum of sports, including cross-country skiing, cycling, marathon running, and rowing. The 10% difference is borne out in the comparison of the best times for men and women in sports as varied as the marathon and the 100-m sprint.
Independent of blood volume, in females, the red blood cells (erythrocytes) have 10% less hemoglobin in the red blood cell composition than that of men. Hemoglobin is the substance within the cell that physically carries available oxygen to the muscle destination where energy is being created and consumed.
The musculoskeletal structures of women and men are identical in terms of the composition of the muscle fibers and the relative proportion of fast-twitch to slow-twitch fibers. Circumstances such as lactate accumulation in the blood, as a byproduct of strenuous exercise, occur in the same fashion in athletes of both sexes. Women engaged in training activities to build their cardiovascular capacity can train using the same principles and approaches as male athletes; it is the maximum training volume that will be of particular concern. In general terms, an elite female athlete should train to 85-90% of the volume of a similar male athlete. Training programs that exceed this limit and in essence emulate a male training regime, particularly in endurance sports, will risk the occurrence of both physical injury and over-training-induced burnout on the part of the female athlete.
The pelvis of a female athlete is proportionately wider than that of a male due to the natural ability of women to become pregnant and to give birth. The width of the female pelvis is a contributing factor to the far greater incidence of the tear of the anterior cruciate ligament (ACL) in the knee.
The physiological differences that are at the root of the comparative abilities of male and female athletes in disciplines where cardiovascular strength is paramount are distinct from the numerous social barriers that inhibited female athletic performance until recent times. Women were not permitted to compete in an Olympic marathon until 1984. But this was due to the attitudes present in the governance of international athletics, not as a result of cardiovascular weakness.