The human brain is hotter than previously thought, sometimes more than 42 degrees

A new study links a daily cycle in brain temperature and survival after traumatic brain injury

According to recent studies, the average temperature of the human brain varies much more than previously thought. This can indicate healthy brain activity. The temperature in the mouth is usually less than 37°C in healthy men and women, but the average temperature in the brain is 38.5°C, and deeper parts of the brain often reach 40°C, especially in women during the day.

בעבר חקירת הטמפרטורה של מוח האדם הייתה תלויה בנתונים שנאספו ממטופלים בטיפול נמרץ עם פגיעה מוחית, כשלעיתים קרובות נחוץ ניטור ישיר של המוח. לאחרונה, שיטה לסריקת המוח בשם ספקטרוסקופיית תהודה מגנטית (MRS) איפשרה לחוקרים למדוד את טמפרטורת המוח באנשים בריאים ללא צורך בהליכים פולשניים כלשהם. אבל עד לאחרונה לא השתמשו ב-MRS כדי לחקור איך טמפרטורת המוח משתנית במשך היום ומבלי להביא בחשבון איך "שעון הגוף" של האדם משפיע על כך.

The extreme temperatures of the brain in healthy people: relatively warm temperatures in women after ovulation in the morning compared to the coldest temperatures in men at night. Lighter yellow indicates warmer temperatures.

Credit: Nina Rzechorzek/MRC LMB/Brain

In the new study, they created the first four-dimensional map of brain temperature in healthy people. This map shows the amazing extent to which brain temperature varies by brain region, age, sex, and time of day, disproving many previous opinions. It is important to note that these results also contradict the common assumption that body temperature and brain temperature are the same.

In a study, recently published in the journal Brain, they also examined data from people with traumatic brain injury and found a high correlation between survival and the presence of daily cycles in brain temperature. These discoveries can help in the diagnosis, medical prognosis and treatment of brain injury.

To study the healthy brain, the researchers recruited 40 volunteers, aged 20 to 40, who were scanned in the morning, afternoon and late evening for one day, in Edinburgh.

הם גם נתנו למשתתפים מנטר פעילות על פרק כף היד, כדי שאפשר יהיה להביא בחשבון הבדלים גנטיים ובאורח החיים בעיתוי של שעון הגוף (השעון הביולוגי) של כל אדם. אצל "ציפורי לילה" ומשכימי קום ידיעת השעה הביולוגית ביום שבה נמדדה כל טמפרטורת מוח איפשרה להביא בחשבון בניתוח את ההבדלים בין השעון הביולוגי של כל מתנדב.

In healthy participants, the average brain temperature was 38.5°C, more than two degrees warmer than the temperature measured under the tongue. In the study it was also found that the temperature of the brain changed according to:

• the time of day
• the area of ​​the brain
• Sex and the ovulation cycle
• the age

The cerebral cortex is usually cooler, but deeper brain structures were often warmer than 40°C, and the highest observed brain temperature was 40.9°C. In all individuals, temperature showed a consistent variation of close to 1°C by time of day, with the highest brain temperatures observed in the afternoon and the lowest in the evening.

On average, women's brains were about 0.4°C warmer than men's brains. This difference between the sexes was most likely caused by the ovulatory cycle because most of the women were scanned in the post-ovulatory phase of the cycle, and their brain temperature was around 0.4°C warmer than that of the women scanned in the pre-ovulatory phase.

The results also showed that brain temperature increased with age in the participants' 0.6-year range, most notably in areas deep in the brain, where the average increase was XNUMX°C. The researchers suggest that the brain's cooling capacity may decline with age and more work is needed to investigate whether there is a link to the development of age-related brain diseases.

לThe scientific article

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