The topic of how sex influences athletic ability is twofold: the acute effects of sexual activity immediately before competition and the profound, long-term physiological differences between biological sexes. For decades, speculation and anecdotal evidence have often overshadowed scientific inquiry, particularly concerning pre-event rituals. A thorough understanding requires separating cultural myths from measurable biological realities that dictate variations in strength, speed, endurance, and recovery. Examining the science reveals distinct mechanisms through which physiological factors interact with an athlete’s peak performance capacity.
Acute Effects of Sexual Activity on Performance
The long-standing cultural belief that sexual activity before a major event drains energy or diminishes aggression is largely unsupported by scientific evidence. Studies investigating the immediate physiological effects of sex on athletes have found no significant negative impact on key metrics like aerobic capacity, muscular strength, or power output. This is true when the activity occurs at least 10 to 12 hours before competition. The energy expenditure during typical sexual activity is minimal, often comparable to walking up two flights of stairs, amounting to only about 25 to 50 calories.
A common concern revolves around the idea that ejaculation causes a drop in testosterone levels, thereby reducing strength or competitive drive. Research indicates that any resulting hormonal fluctuations are small and transient. These changes have no measurable effect on the body’s ability to perform. Some studies even suggest that sexual activity can transiently increase testosterone levels, though this change is also too minor to be performance-enhancing.
The primary factor that can negatively affect an athlete is not the sexual activity itself but the potential for sleep deprivation or psychological distraction. If sexual activity occurs too close to the event, such as within two hours, it may elevate resting heart rate, though this effect resolves quickly. Ultimately, the most significant effects appear to be psychological. Some athletes report beneficial relaxation and reduced anxiety, while others may experience distraction or a perceived loss of competitive focus.
Inherent Physiological Differences Between Biological Sexes
The most pronounced differences in athletic performance are rooted in the baseline hormonal and structural distinctions between biological sexes, which become evident after puberty. The significantly higher baseline levels of testosterone in males drive the development of greater lean muscle mass and larger bone density. On average, the absolute whole-body strength of female athletes is approximately 63.5% that of male athletes, with upper body strength differences being even more pronounced.
These hormonal differences also influence cardiorespiratory capacity, a major determinant of endurance. Males generally possess larger hearts relative to body size, greater lung capacity, and a higher oxygen-carrying capacity. This is due to a larger blood volume and red blood cell count. This contributes to a higher maximal oxygen consumption (VO2 max), providing a distinct advantage in aerobic events.
Across all sports, these physiological factors contribute to a performance gap that can range from a 10% difference in distance running to over 30% in strength-based disciplines like weightlifting. Female physiology, however, offers certain metabolic advantages, particularly in ultra-endurance events. Estrogen promotes a metabolic shift that favors the utilization of fat as a primary fuel source during prolonged aerobic exercise. This “fat-sparing” effect can delay glycogen depletion, potentially allowing female athletes to maintain effort for extended periods.
Structural differences also manifest in biomechanics and injury risk. Females typically have wider pelvic structures, which creates a greater Q-angle—the angle formed by the thigh bone and the shin bone at the knee. This altered alignment can affect movement patterns. It is a contributing factor to the higher incidence of certain injuries, such as anterior cruciate ligament (ACL) tears, which are up to six times more frequent in female athletes participating in jumping and cutting sports.
Cyclical Hormonal Fluctuations in Female Athletes
Beyond the inherent baseline differences, performance in female athletes is subject to cyclical fluctuations driven by estrogen and progesterone during the menstrual cycle. The cycle is broadly divided into two main phases: the follicular phase and the luteal phase, each presenting distinct hormonal environments. The follicular phase, running from the start of menstruation to ovulation, is dominated by rising estrogen levels.
During the late follicular phase, coinciding with the peak of estrogen just before ovulation, some studies suggest a slight increase in strength and power output. This phase is also associated with faster reaction times and a perceived boost in energy levels. However, the subsequent ovulatory phase, marked by a sharp hormonal peak, has been linked to temporary increases in ligament laxity. This may increase the risk of soft tissue injury.
The luteal phase, which follows ovulation, is characterized by high levels of both estrogen and progesterone. Progesterone can elevate the athlete’s core body temperature, which may present a challenge for temperature regulation and sustained performance in hot environments. Female athletes frequently report a subjective feeling of worse performance during the late luteal phase, often accompanied by symptoms such as fluid retention and mood changes.
While objective performance tests often show only trivial differences between phases, a personalized approach to training is often recommended. This approach accounts for an individual athlete’s symptomatic response to these hormonal shifts.