A recent study published in the journal Brain suggests that the daily brain temperature cycles are strongly correlated with survival. In healthy men and women, the oral temperature is less than 37°C whereas the average brain temperature is 38.5°C, with deeper brain regions often exceeding 40°C, particularly in women during the daytime.

The new study conducted at the Medical Research Council (MRC) Laboratory in the UK has developed the first-ever 4D map of healthy human brain temperature. This map has enabled the researchers to study the variation in brain temperature by brain region, age, sex, and time of the day. The study included 40 volunteers between the ages of 20-40 years. The subjects were given a wrist-worn activity monitor to monitor the genetic and lifestyle differences based on the timing of each persons body clock, or circadian rhythm. The participants were segregated into both night owls and morning larks, to record the brain temperature at different time-of-day to allow the differences between each volunteers body clock to be factored into the analysis.

In healthy participants, the brain temperature was 38.5°C with a variation based on time of day, brain region, sex and menstrual cycle, and age. The deeper regions of the brain were found to have a higher temperature of 40°C, with the highest temperature recorded as 40.9°C. The brain showed a variation of 1°C on average throughout the day, with the highest temperature observed in the afternoon. Meanwhile, the brain temperature of the female population was found to be 0.4°C higher than the male counterpart. The researchers attributed this variation to the menstrual cycle. Also, the females in the pre-ovulation stage showed a cooler brain temperature of 0.4°C in comparison to ladies in the post-ovulation stage. Similarly, the temperature in the younger participants (20-30 years) in comparison to older cohorts was found to be lower by 0.6°C on average.

Hence, it was concluded that an increased age may deteriorate the brain’s cooling capacity which can be associated with the development of age-related brain disorders.

(Source: https://www.hindustantimes.com/lifestyle/health/study-normal-human-brain-temperature-varies-much-more-than-previously-thought-101655266067413.html )