What Happens While You Sleep?

Sleep is not downtime — it is one of the most metabolically active periods of your day. During deep sleep, the brain's glymphatic system flushes out waste products including amyloid plaques linked to Alzheimer's. The pituitary gland releases growth hormone for tissue repair. Memory consolidation occurs during REM sleep. The immune system synthesises cytokines to fight infection.

How Much Sleep Do Adults Actually Need?

The National Sleep Foundation recommends 7–9 hours for adults. Research consistently shows that people who sleep fewer than 6 hours per night perform as poorly on cognitive tests as those who have been awake for 24 hours — and most don't notice the impairment.

What Chronic Sleep Deprivation Does to the Body

  • Metabolic disruption — just one week of poor sleep alters insulin sensitivity, raising diabetes risk
  • Weight gain — sleep deprivation elevates ghrelin (hunger hormone) and suppresses leptin (satiety hormone)
  • Cardiovascular strain — sleeping under 6 hours is associated with a 20% higher risk of heart attack
  • Immune suppression — people who sleep less than 7 hours are nearly 3× more likely to develop a cold when exposed to the virus
  • Mental health — insomnia is both a symptom and a driver of anxiety and depression

Practical Steps to Improve Sleep Quality

Keep a Consistent Schedule

Going to bed and waking at the same time every day — including weekends — is the single most powerful way to strengthen your circadian rhythm.

Protect the Last Hour Before Bed

Blue light from screens suppresses melatonin production. Dim lights, switch devices to night mode, or use blue-light blocking glasses after sunset.

Keep the Bedroom Cool and Dark

Core body temperature needs to drop by 1–2°C to initiate sleep. A room temperature of 18–20°C is optimal for most people. Blackout curtains or a sleep mask improve sleep depth.

Limit Caffeine After 2 pm

Caffeine has a half-life of 5–6 hours. A coffee at 3 pm still has 50% of its stimulant effect at 8 pm.

Wind Down With a Relaxing Routine

Reading, light stretching, or a warm shower signals to the brain that sleep is approaching. Avoid stressful conversations or work in the 30 minutes before bed.

When to See a Doctor

If you regularly take more than 30 minutes to fall asleep, wake frequently through the night, or feel unrefreshed despite 8 hours in bed, speak to a doctor. Conditions like sleep apnoea or restless leg syndrome are treatable and often overlooked.