6LETTERS

In fact, the important thing is knowing 'my hormone rhythm'.

by Senior's Know-how l  May 21, 2026

These days, 

people classify others quite easily.

“Are you totally a lose-in-the-day, win-at-night' style?”

“He seems like a lose-at-night, win-in-the-day.”

“No, that person is a win-at-night, win-in-the-day.”

At first, I thought it was just an internet meme. 

But looking at it, quite an interesting question arose.

Does the time when “vitality rises” really differ for each person?

And could that difference be not simple personality, 

but a difference in hormones and biological rhythms?

Thinking about it, science is providing quite a serious answer to this.

Humans Do Not All Move according to the Same Timetable

Someone opens their eyes at 6 AM and is ready to conquer the world.

On the other hand, 

someone else's concentration suddenly explodes starting from 11 PM.

What's interesting is that this difference is not a simple habit, 

but is related to a biological characteristic called Chronotype.

Simply put:

• Morning person

• Evening person

• Intermediate person

It is the same concept.

And this difference is not a simple matter of mood, 

but is actually connected to rhythms of hormones 

such as sleep, body temperature, cortisol, melatonin, and testosterone.

The Problem is That Hormones Keep Changing All Day Long

In particular, testosterone moves very significantly within a day.

According to research:

• Normal men's testosterone starts rising after the onset of sleep,

• Reaches its peak during the first REM sleep period,

• And can fluctuate close to 30–50% during the day.

•  

In other words, 

the hormone level measured at 3 PM and 

the level measured at 7 AM can have completely different meanings.

What's more interesting is that the "shape of this curve" itself varies 

from person to person.

So in Fact, There Are Far More Than Four Types of People

The internet always wants to divide people into two.

However, reality is much more complex.

For example:

Mild during the day, but confidence rises at night 

->  Lose in the day, win at the night

• Full of energy during the day, but gets completely discharged at night

• ->  Lose at the night, win in the day

•  

• Sleepy during the day, and sleepy at night 

• ->  Lose in the day, lose at the night

• 
  

• Alive during the day, and doesn't die at night  

• ->  Win at night, win in the day

• 
  

However, physiologically speaking, these differences make sense more than you think.

Because for each person, the following are different:

• Melatonin secretion timing

• Cortisol arousal point

• Sleep pattern

• Testosterone rhythm

• Autonomic nerve activity

Even the Time You Fall Asleep Has an Effect

 

 

What's interesting is that 

research shows the increase in testosterone is not simply "because it's morning," 

but is deeply connected to "sleep itself."

In particular, if sleep duration is insufficient or sleep structure is broken, 

there are results showing that testosterone levels the next day can decrease significantly.

In other words:

• A person sleeping at 2 AM

• A person sleeping at 10 PM

• A night-shift worker

• A person whose sleep pattern collapses every weekend

•  

This means that even if they are the same human, they can live on completely different hormone rhythms.

So the Important Thing is Not the “Correct Answer Time”

 

 

We always try to find the correct answer.

“Morning exercise is the best.” 

“Waking up at dawn is the secret to success.” 

“Productivity drops at night.”

But is that really true for everyone?

Recent studies say that maintaining a lifestyle pattern that
fits one's chronotype may rather be more important 

for sleep, metabolic health, cardiovascular health, and exercise efficiency.

In other words, what matters is:

It might not be the "good time" set by others, 

but finding the time when my body actually moves best.

In the End, What's Important is

 

 

“When am I most like myself?”

Some people recover at dawn, 

and some people's creativity comes alive at night.

For someone, morning exercise fits their body, 

and for someone, night exercise is far more efficient.

And behind that difference, sleep, stress, autonomic nerves, hormones, 

and biological clocks are intertwined.

So perhaps health is not living on the same timetable for everyone, 

but a process of gradually understanding my body's rhythm.

Because more important than whether you lose in the day and win at night or lose at night and win in the day,

is ultimately knowing 

“when does my body come alive the most.”