Fez – For generations, doctors and medical textbooks cited 36.6°C as the benchmark for “normal” body temperature. Modern studies now show that healthy individuals often register closer to 36.4°C — and in some populations, even lower.
The shift has been documented by a research team led by Professor Michael Gurven at the University of California, Santa Barbara. Their findings indicate that this cooling trend is not random, but a physiological response to improved living conditions.
Access to cleaner environments, better nutrition, fewer infections, and advances in healthcare have reduced the body’s need to sustain higher temperatures. Historically, a warmer body helped fight infections. Today, widespread vaccination, antibiotics, safe drinking water, and modern sanitation have lessened that need.
Temperature-controlled living spaces are another factor. With heating and air conditioning now common in much of the world, our bodies expend less energy regulating temperature. Even in countries with extreme seasonal changes, climate-managed homes have reduced the strain on our internal systems.
The trend is not limited to high-tech societies. Among the Tsimane, an Indigenous group in Bolivia with minimal exposure to modern amenities, average body temperature has dropped by 0.05°C per year, now averaging 36.5°C. Researchers attribute this to gradual changes in healthcare access, nutrition, and social conditions.
A cooler baseline temperature does not indicate declining health. Instead, it reflects the body’s adaptation to a world with fewer disease threats and more stable living conditions.
The long-held belief in a single “normal” body temperature is giving way to a more flexible understanding. Factors such as age, location, time of day, and lifestyle can all influence readings.
Temperature is no longer a one-size-fits-all number — and that is a sign of how human health has evolved.
