Caffeine and sleep: why that cup of coffee can disrupt your night
For many people, the day starts with a cup of coffee. That makes sense. Caffeine helps you feel more alert and stay awake.
What many people don’t realise is that caffeine can still affect your sleep hours later, even if you no longer feel wired or restless in the evening.
Why do you get sleepy at night?
While you’re awake, your body steadily produces a substance called adenosine. Think of it as your body’s natural sleep signal.
The longer you stay awake, the more of this “sleep substance” builds up. That creates growing sleep pressure, the natural need to go to bed.
By the end of the day, sleep pressure is at its highest. Your body is sending a clearer and clearer message that it’s time to sleep.
What does caffeine do?
Caffeine doesn’t remove tiredness. It temporarily hides the signal that you’re tired.
Normally, adenosine tells your brain it’s time to sleep. Caffeine temporarily blocks that signal. You feel more awake and less sleepy, while your body continues to build up fatigue in the background.
Once the caffeine wears off, the sleep signal returns. Because adenosine has been building up the whole time, you can suddenly feel very tired.
Caffeine stays in your body longer than you think
Many people assume a cup of coffee wears off after a few hours. In reality, it takes much longer.
On average, every cup of coffee, cola, or energy drink needs about 5 to 7 hours before half of the caffeine has left your system.
Drink a coffee at 7:30 p.m., for example, and around 12:30 a.m. roughly half of that caffeine can still be active. That can make it harder to fall asleep, or to sleep as deeply.
For some people it takes even longer. That depends on factors like age, genetics, and certain medications.
Tea, chocolate, and decaf contain caffeine too
Caffeine isn’t only in coffee. You’ll also find it in:
• Black tea
• Green tea
• Energy drinks
• Cola
• Dark chocolate
• Some painkillers
• Decaf coffee (still contains a small amount of caffeine)
Several cups of decaf in the evening can still affect your night’s rest.
Tips for better sleep
Better sleep often starts earlier in the day.
- Have your last coffee or cola 6 to 8 hours before bed.
- Later in the day, choose water or herbal tea without caffeine.
- Stick to consistent bedtimes as much as you can.
- Keep your bedroom cool, dark, and quiet.
- Sleep under a clean, fresh duvet.
A fresh sleep environment helps too
What you do during the day affects your sleep. So does the room you sleep in. A clean bed feels better and helps you wind down for the night.
With a washable Plumelle duvet, you don’t only wash the cover, you can wash the entire duvet at home at 60 °C. That means you can sleep under a fresh duvet every night, without the hassle of a separate duvet cover.
Good sleep starts with small habits. Less caffeine in the evening and a fresher sleep environment can already make a big difference together.
