Why Sleep Matters for Your Health
Sleep affects every part of your physical, mental, and emotional health. While you sleep, your body repairs cells, builds new connections, and restores energy. Your brain also clears out toxins that build up during the day. This reset helps you wake up focused and ready.
When you don’t get enough sleep, your body misses this reset. Fatigue sets in. Your immune system weakens. Your mind feels foggy, and your emotions become harder to manage.
The four stages of sleep
Understanding the stages of sleep and deep sleep helps you see why quality sleep matters. Sleep has four stages: three stages of non‑REM sleep and one stage of REM sleep. Your brain activity changes in each stage.
Non-REM Sleep
Stage 1: Light Transition
You move from wakefulness into sleep. This stage lasts only a few minutes.
Stage 2: Light Sleep
Your body relaxes. Your temperature drops. Your heart rate and breathing slow down.
Stage 3: Deep Sleep
Stage 3 is slow‑wave sleep, also called deep sleep. Your breathing and pulse slow even more. Deep sleep restores your body, strengthens your immune system, and supports memory and creativity. This is the most restorative stage of sleep.
REM Sleep
REM sleep activates your brain. Your eyes move quickly, and your muscles relax to prevent you from acting out dreams. Your body struggles to regulate temperature during REM, which is why you may feel cold if you wake early in the morning. Your heart rate increases, and your breathing becomes irregular.
Read also: The connection between endorphins, sleep and memory
how long you spend in each stage
Your body cycles through all four stages in about 90 minutes. Most people complete four to six cycles each night.
You get more deep sleep in the first half of the night. Deep sleep supports immune function and creative problem‑solving. As the night continues, deep sleep decreases and REM sleep increases.
By early morning, REM sleep dominates. This shift explains why dreams feel more vivid when you wake up. REM sleep helps you process emotions and move memories from short‑term to long‑term storage.
On average, you spend about half the night in light sleep and about 20–25% in both deep sleep and REM sleep.
signs you’re not getting enough deep sleep
If you wake up tired, you may not be getting enough deep sleep. Even with a solid bedtime routine, you can try a few strategies to increase restorative sleep.
Read also: How much sleep do I need?
If you have a solid bedtime routine, you might try incorporating one of the following tips to try to increase the amount of deep sleep you get each night.
1. Take a Hot Shower
A hot shower warms your body. When you step into cooler air, your core temperature drops quickly. This drop helps your body enter deep sleep faster.
2. Turn Off Screens
Blue light from screens can suppress melatonin. Put away devices 1–3 hours before bed.
3. Dim the Lights
Bright lights can delay melatonin production. Use softer lighting as bedtime approaches.
4. Adjust Your Bedroom Temperature
Keep your room around 65°F (18°C). A warm room can reduce deep sleep.
5. Exercise Earlier in the Day
If evening workouts disrupt your sleep, try exercising in the morning. This gives your body time to recover before bedtime.
improving sleep takes time
Sleep is complex, and many factors influence it. Consistency matters more than perfection. When you prioritize sleep, you support your health, mood, and daily performance. New habits may feel challenging at first, but the benefits build quickly once you commit to them.