Research reveals that men are affected by daily hormonal cycles

Most people know that women deal with the effects of their hormones throughout their lives, and even throughout a single day. But now a study has shown that men are also affected by hormonal changes.

The research tracked the brain of a 26-year-old man for a month and showed something impressive: that its size decreases throughout each day and then returns to its initial state the next day.

Hormones in a man’s brain

The study involved scanning the brain of a 26-year-old man 40 times over the course of 30 days. This is done through an MRI that is performed, in most cases, twice a day, at 7 a.m. or 8 p.m. The reason for this time is that these are the times when steroid hormones (testosterone, cortisol, and estradiol) are at their highest or lowest levels.

The group’s analysis suggests that the daily flow of hormones in the male body plays a role in brain shrinkage over the course of a day. In other words, after losing volume between morning and evening, the brain “reboots” itself at night, starting the hormonal cycle again.

According to Laura Pritchett, a postdoctoral fellow in psychiatry at the Perelman School of Medicine at the University of Pennsylvania, the degree of change changes with age, but it never stops happening. “Men show a 70% morning-to-night drop in steroid hormones,” he told Live Science.

She also compared the results to what was observed in women, which involves a daily flow of hormones that is not as pronounced as in men. “You can think of it as a pulsating rhythm from morning to night,” he added.

Why is this happening?

The new study revealed that over the course of the day, the total volume of the brain decreased, as well as the thickness of the cortex, which is the outer layer of the brain. But the part he chose most were two specific areas, known as the occipital and parietal cortex.

Other changes were noted in brain structures, which include the cerebellum, brainstem, and parts of the hippocampus. These are areas involved in coordinating movement, transmitting information between the brain and body, and storing memories.

What the researchers ultimately found is that the decrease in brain size goes hand in hand with the daily decrease in hormones. However, it is still unclear whether hormones caused this effect.

“This is still an open question, but it is another example that debunks the myth that hormones are only relevant to women,” said Elle Murata, a doctoral candidate in psychology and brain sciences at the University of California, Santa Barbara.

She points to the fact that previous research has shown that steroid hormones, which are molecules that are transported to organs and other tissues to regulate physiological processes, make up the brain. In other words, the hormones associated with the menstrual cycle are not the only ones capable of affecting the brain, and perhaps even mood.