Lesson 4 · The Science of Sleep

Sleep Like a Junior,
Not to Age Like a Senior

Your brain washes itself at night, your hormones reset, and your body repairs. Sleep is not rest — it’s the most productive thing you do all day.

0a

Warm-up Video

Watch the video and get ready to discuss.

drive.google.com → Sleep warm-up
0b

Guessing

What do you think are the best times for these activities?

0c

Read These Facts About Sleep

Read and react. Which fact surprises you most?

🧠 Your brain does NOT rest while you sleep. It works 10 times harder than during the day, literally washing away toxins. Without this clean-up, within 2 weeks you’d develop dementia.

💤 People who sleep less than 6 hours live 15 years shorter. Immunity drops by 70%, cancer risk doubles, the heart wears out.

🛌 Sleeping in on the weekend is a dangerous illusion. Each night the brain needs 4–6 full sleep cycles. One sleepless night kills as many brain cells as you can’t recover in a month.

🍷 Alcohol does NOT help you sleep. Alcohol blocks REM sleep — the phase that restores memory and emotions. You slept 8 hours, but your brain didn’t recover.

🌡 Bedroom temperature matters more than hours of sleep. Above 20°C (68°F), your body can’t reach deep sleep. The sweet spot: 16–18°C (60–64°F). At this temperature, 6 hours restore you better than 9 hours in the heat.

🌕 Streetlight through your curtains cuts growth hormone by 50%. Even dim light blocks melatonin. The perfect bedroom: pitch-dark, silent, cool.

🐦 Early birds live longer than night owls — not because they wake up earlier, but because they sleep at the right time. Melatonin starts at 9 PM and peaks at 3 AM. Night owls who go to bed after midnight miss half of their recovery.

I

Vocabulary

Study the words. Click 🔊 to hear pronunciation.

II

Match the Words with Their Definitions

Click a word, then its definition. Either side first.

Word
Definition
All matched correctly!
III

Fill in the Blanks

Choose a word from the bank and click the blank to fill it.

IV

Questions

Answer in English. Use the vocabulary from Tab I.

V

Circadian Rhythms: Your Body’s 24-Hour Clock

Read carefully. Pay attention to the body clock table.

What are circadian rhythms?

They are your body’s internal 24-hour clock. This clock tells you when to wake up, feel sleepy, eat, and be active. The master clock lives in your brain (in the hypothalamus) and is controlled mainly by light.

Circadian rhythms control:

  • Sleep and wakefulness
  • Hormones (melatonin, cortisol, growth hormone)
  • Body temperature
  • Energy levels and focus
  • Digestion and appetite

What happens if you break your rhythms?

  • Poor sleep quality
  • Trouble concentrating
  • Weaker immune system
  • Faster aging and higher risk of diseases (heart problems, diabetes, depression)

To boil it down

Your circadian rhythms are like a built-in clock. If you respect it, you’ll sleep better, have more energy, and stay healthier.

🕒 Your Daily Body Clock

TimeWhat HappensKey HormonesPro Tips
VI

True or False?

Click True or False. Your answer checks immediately.

VIII

Put in the Correct Order & Add Times

Drag and drop the activities into your ideal order, then add your preferred time in the field next to each one.

IX

Discussion Questions

Answer in English. Use the vocabulary. No right or wrong answers.

Xa

Blue Zones — Flip Cards

Click a card to flip it.

Click a card to reveal the translation and example

Xb

Blue Zones — Complete the Sentences

Finish each sentence in a way that makes sense.

Xc

Biohacking — Explain in Your Own Words

Write a sentence for each concept.

Xd

Food — Vocabulary Flip Cards

Click a card to reveal the translation and example.

Click a card to flip it

Xe

Food — Fill in the Gaps

Choose words from the bank and fill the blanks.

Xf

Food — Match the Questions to Answers

Click a question, then its answer. Either side first.

Question
Doctor’s Answer
All matched!
Xg

Food — Match the Words with Definitions

Click a word, then its definition. Either side first.

Word
Definition
All matched!
Grow stronger in English and sharper in thinking — every word counts, every idea matters.