The First 90 Minutes of Sleep: The Key to Better Performance

Hello everyone, this is Sho Ito from Wrestling Lab.

Last time, we talked about the stubborn challenge of “sleep debt.”
But let’s be honest — in our busy daily lives, sleeping 14 hours a day just isn’t realistic.

So this time, I’d like to focus on a more practical question:
“How can we improve the quality of our sleep?”

🗝️ The Key to Better Sleep Lies in the First 90 Minutes
🔄 How to Optimize the First 90 Minutes: Activate the “Sleep Switches”
1. 🔥 Sleep Switch #1: Body Temperature
2. 🧠 Sleep Switch #2: The Brain
🧬 Sleep: Your Ultimate Recovery and Performance Tool
📝 Summary
📕 Book Announcement
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🗝️ The Key to Better Sleep Lies in the First 90 Minutes

Let’s get straight to the point:
The key to getting the best sleep lies in the first 90 minutes after falling asleep.

Why?
Because this is when we experience the deepest phase of non-REM sleep, also known as deep sleep.
Our bodies cycle between deep non-REM and lighter REM sleep, but as morning approaches, REM sleep becomes more dominant and we naturally begin to wake up.

By improving the quality of just those 90 minutes, you’ll begin to see amazing benefits:

Improved autonomic nervous system function:
A disrupted autonomic system can lead to a variety of health issues, but deep, high-quality sleep in the first 90 minutes helps restore balance.
Abundant growth hormone release:
While we often associate growth hormone with children, it’s essential for adults too — it promotes cell regeneration and slows aging.
It’s said that around 80% of our daily growth hormone secretion occurs during this first deep-sleep phase.

Even if you sleep for 8 hours, poor quality in the first 90 minutes can drastically reduce the overall quality of your rest.

🔄 How to Optimize the First 90 Minutes: Activate the “Sleep Switches”

So how do we actually improve the quality of that crucial first phase?

It’s all about skillfully activating two key “sleep switches”:

🔥 Sleep Switch #1: Body Temperature

Take a bath 90 minutes before bed 🛀
Raising your core temperature temporarily through a warm bath helps trigger a gradual cool-down — this natural decline in body temperature makes it easier to fall asleep.
(Hot springs are even more effective!)
Control your bedroom temperature ❄️
In Japan, many people rely on fans in summer and thick blankets in winter to regulate temperature.
However, consistent ambient room temperature is far better for sleep quality.
Use your air conditioner’s sleep mode to keep your room comfortable, especially in summer — overheating and excessive sweating can lead to overcooling and even colds.

🧠 Sleep Switch #2: The Brain

Leverage the “Monotonous Rule”
“Monotonous” simply means boring or repetitive — the kind of mental state that helps ease your brain into sleep.
A bedtime routine can reinforce this:
- Go to bed at the same time
- Sleep in the same bed
- Wear the same pajamas
- Use the same lighting and room conditions
- Listen to the same soft, repetitive music if needed
Avoid stimulating your nervous system before bed 📵
Many of us scroll through social media before sleeping. But smartphone use right before bed activates the sympathetic nervous system and makes it harder to fall asleep.
To protect your “golden 90 minutes,” put your phone away before bedtime!

🧬 Sleep: Your Ultimate Recovery and Performance Tool

Why is sleep so important in the first place?

Research from Stanford University showed that athletes who extended their sleep time saw dramatic performance improvements — not due to supplements or more training, but purely from adequate sleep.

Once they returned to normal sleep schedules, their performance dropped again — proof that sleep alone was the game-changer.

“Practice makes perfect” is true, but high-quality practice requires high-quality recovery.
Good sleep improves not only muscle recovery but also brain functions like learning, memory, and decision-making — ultimately speeding up skill acquisition.

So yes — “Sleep helps you grow” is true for all generations, not just for kids.

📝 Summary

What did you think?

Today we explored how to improve sleep quality — especially the critical first 90 minutes after falling asleep.
Start applying these “sleep switches” tonight and see how your body and mind respond!

This post concludes my four-part series on sleep and performance.

If you want to dive deeper into the science behind sleep, I highly recommend the book:
📘 The Stanford Method for Ultimate Sleep by Seiji Nishino (Sunmark Publishing, Japanese)