Understanding Sleep: A Science-Based Guide

The Hormones That Control Sleep

Sleep is controlled by two key systems:

1. Circadian Rhythm (Your Body Clock)

• It’s a 24-hour cycle that tells your body when to sleep and wake.
  
  
• Light affects it — especially sunlight and blue light from screens.
  
  
• Controlled by a part of your brain called the suprachiasmatic nucleus.
  
  

2. Sleep-Wake Hormones

• Melatonin: Released when it gets dark. Makes you feel sleepy.
  
  
• Cortisol: Wakes you up in the morning and helps you feel alert.
  
  
• Adenosine: Builds up during the day — makes you feel more tired the longer you’re awake.
  
  

Sleep Stages: What Happens While You Snooze?

Your sleep goes in cycles, about 90 minutes each, and includes these stages:

1. Stage 1: Light Sleep
   
   
   
   • Lasts a few minutes, easy to wake up.
     
     
2. Stage 2: Deeper Sleep
   
   
   
   • Heart rate slows, body starts to relax.
     
     
3. Stage 3: Deep Sleep (Slow-Wave Sleep)
   
   
   
   • Body repairs itself, immune system strengthens. Hard to wake up.
     
     
4. REM Sleep (Rapid Eye Movement)
   
   
   
   • Brain is active. You dream. Important for memory and learning.
     
     

💡 Fun Fact: You go through these stages 4–6 times each night!

How Much Sleep Do You Really Need?

‍

Age Group

Hours of Sleep Needed

Kids (6–12 years)

9–12 hours

Teens (13–18 years)

8–10 hours

Adults (18–60+)

7–9 hours

Behavior: How to Sleep Better (Sleep Hygiene Tips)

Your actions during the day and night affect your sleep. Here’s what helps:

‍

Good Habits

• Go to bed and wake up at the same time every day.
  
  
• Get sunlight in the morning to reset your body clock.
  
  
• Keep your room cool, quiet, and dark.
  
  
• Limit screens an hour before bed — they reduce melatonin.
  
  
• Exercise during the day, but not too close to bedtime.
  
  
• Use your bed only for sleep (not homework or scrolling TikTok).
  
  

Avoid These

• Caffeine (soda, coffee, energy drinks) in the afternoon or evening
  
  
• Heavy meals or sugar right before bed
  
  
• Staying up super late on weekends (“social jet lag”)
  
  

What Happens If You Don’t Get Enough Sleep?

• Trouble focusing in school
  
  
• Worse memory
  
  
• Mood swings or anxiety
  
  
• Weakened immune system
  
  
• Slower physical recovery
  
  

Sleep is like charging your phone. Skip it, and your brain battery runs out fast.

Final Thought

Sleep isn’t lazy — it’s smart. It helps you grow, focus, heal, and be your best.

So next time you think about staying up too late, remember:

Great days start with great nights.

‍