The human body constantly works to maintain a stable internal temperature, a process known as thermoregulation. This system relies on a balance between the heat the body generates and the heat it loses. The common observation that men often feel warmer than women is rooted in several physiological differences that affect this thermal balance. On average, men operate with a higher baseline heat output and have different mechanisms for heat retention and dissipation.
The Engine: Basal Metabolic Rate and Heat Generation
Heat is an inherent byproduct of converting energy from food into cellular energy. This baseline energy expenditure, known as the Basal Metabolic Rate (BMR) or Resting Metabolic Rate (RMR), is the primary source of the body’s internal heat. Men typically have a BMR significantly higher than women, even accounting for differences in body weight. This higher metabolic rate means men are constantly generating more heat simply to maintain basic life functions while at rest.
The cellular processes that burn calories are not perfectly efficient; a large portion of the energy released is lost as thermal energy. Studies show that men can exhibit a resting energy expenditure hundreds of kilocalories higher per day compared to women, translating directly into a greater volume of metabolic heat production. This higher rate of heat output establishes a consistently warmer core temperature that the body must manage.
Muscle Mass and Insulation: Body Composition Differences
The primary reason for the higher BMR in men lies in body composition, specifically the proportion of muscle to fat tissue. Muscle tissue is metabolically active, requiring and burning energy even when the body is at rest. Muscle cells consume far more energy than adipose (fat) tissue, generating a substantial amount of heat as a result.
Men generally possess greater overall muscle mass and a lower percentage of body fat compared to women. This higher ratio of heat-generating muscle tissue leads to an increased baseline of internal heat production. While fat acts as an insulator, retaining heat, the sheer volume of heat produced by greater muscle mass is the dominant factor in maintaining a higher core temperature.
Hormonal Drivers: How Testosterone Affects Thermoregulation
Sex hormones play a regulatory role in the body’s thermal set point and its mechanisms for cooling. Testosterone, the primary male sex hormone, influences thermoregulation through multiple pathways. It is the driving force behind greater muscle development, linking the hormone to increased heat production from metabolically active tissue.
Testosterone also affects the body’s cooling responses, particularly the sweating mechanism. Higher levels of the hormone increase the activity of sweat glands and influence the brain’s temperature control center, the hypothalamus. While women have more sweat glands, men typically exhibit a higher sweat rate and volume when exposed to heat, initiating the cooling process sooner. The hormonal balance in women causes cyclical fluctuations in core body temperature, whereas men’s testosterone-driven thermal state tends to be more consistently elevated.
Subjective Comfort: Differences in Thermal Perception
The perception of being “hot” is not solely determined by core body temperature; skin temperature and preferred surrounding air temperature also matter. Research indicates a distinct difference in the thermal comfort zone between men and women. Women often prefer ambient temperatures several degrees warmer than those preferred by men.
This difference means that in standard settings, often calibrated to a male thermal preference, women are more likely to feel cold while men feel comfortable or too warm. The skin temperature of the extremities, such as the hands and feet, is also a major factor in subjective comfort. Women often have lower skin temperatures in these areas, contributing to a feeling of being colder even if their core temperature is similar to a man’s. This discrepancy contributes significantly to the common experience of men feeling “always hot.”