Sleep and Caffeine: How to Optimize Caffeine Intake for Better Sleep

man sleeping on bed with white t shirt


Many of us love caffeine. So much so that we can’t really function well without it. It’s actually less common today to find someone who doesn’t have caffeine as a part of their daily routine.

Caffeine itself is not necessarily a bad thing. The strong jolt and increased focus from a cup of coffee can help you get more done, or help you wake up and get going early in the morning. But there are some downsides. Most notably, it can affect your sleep, which goes on to have a whole range of negative health effects.

Chances are you don’t want to give up caffeine altogether, but the last sentence may have set off a lightbulb in your head if you’re someone who struggles to get high-quality sleep. 

If that’s you, keep reading. We’ll share some tips on how to enjoy your caffeine habit without it ruining your chance of a good night’s sleep.


How Much Caffeine Each Day is Too Much?

For most people, caffeine is safe if taken in moderation. It’s when you take too much that it starts to become a problem.

The FDA recommends an upper limit of 400 milligrams per day for healthy adults. For reference, a regular cup of coffee generally contains around 80-100 mg of caffeine. So the recommended limit would be equal to 4 or 5 cups of coffee in a day.

Above this amount, you’re likely to start experiencing negative side effects and potential negative health consequences. However, that 400 mg mark will differ from person to person. Some are more sensitive to caffeine than others, and therefore may feel side effects from just 200 mg, for example.

The toxic limit is much more - around 1200 mg of caffeine, consumed in a short space of time. But realistically, you shouldn’t be going anywhere near the level for caffeine to become toxic to your health.

Benefits of Caffeine

rich espresso pouring into 2 glass cups

Coffee does offer some health and performance benefits, as long as you don’t overdo it. Here’s a quick summary:

  • Caffeine boosts energy, decreasing fatigue and making you feel more alert.
  • Caffeine may also boost athletic performance (especially when combined with creatine), particularly in terms of endurance.
  • Coffee consumption appears to be linked to a lower risk of liver disease.
  • Moderate caffeine consumption may lower the risk of heart disease and stroke.
  • Caffeine can act as an appetite suppressant and help with weight loss.

Downsides of Caffeine

Caffeine also comes with downsides, like potential negative reactions or side effects, including the following:

  • Anxiety.
  • Jitters.
  • Elevated heart rate.
  • Insomnia.
  • Digestive problems or diarrhea.
  • Energy crashes when the effects of caffeine wear off.
  • Dependence and addiction (leading to withdrawal symptoms).

Not everyone will feel the same negative effects from caffeine. It depends on your personal tolerance for caffeine, as well as your intake. In moderation, it’s generally fine, but higher levels make it more likely to experience side effects.

How Does Too Much Caffeine Affect Sleep?

Where caffeine starts to affect your sleep is in its relationship with adenosine.

Adenosine is a chemical that’s naturally produced in the body. In the brain, it inhibits the central nervous system, and promotes a feeling of calm and relaxation.

There’s a very strong link between adenosine levels and sleep cycles. When adenosine is high, we feel sleepy. When it’s low, we are more energized and alert - a drop in adenosine levels is usually what causes us to wake up in the morning.

Caffeine blocks the adenosine receptors in the brain, which is part of why it makes us feel more awake - it’s blocking the brain from picking up on the chemical that makes us feel sleepy.

That’s great if it’s early in the morning, and you’re trying to shake off sleep and get to work. But if caffeine is still active in the body later in the day, it becomes a problem, blocking the body’s natural sleep cycle from kicking in.

So instead of feeling sleepy and nodding off, you lie in bed feeling wired and alert, wondering why you can’t just fall asleep.

You could have taken too much caffeine, which your body can’t process and expel from your system in time for sleep; or you may have taken caffeine too late, in which case it’s still active at this time. Either way, it is proven to have negative effects on sleep quality.

young woman sleeping with eye mask on


When to Consume Caffeine

You can avoid caffeine from interfering with your sleep by limiting your caffeine consumption later in the day.

Caffeine has a half life of approximately 5 hours, which means the average time that most of the caffeine you take remains active in your system.

With this information in mind, you want to avoid taking caffeine within 5-6 hours before you intend to go to sleep, to avoid any interference.

Realistically, some people process caffeine at a slower rate than this, so it’s best to leave even more time for it to leave your system. A safer rule is to avoid caffeine within 10 hours of sleep. Assuming you go to sleep somewhere between 10pm and 12am, that would mean essentially staying away from caffeine from the afternoon onwards.

How to Limit Caffeine Later in the Day

tub of Naked Nutrition Stim Free Naked Energy


The simplest solution to avoid caffeine interfering with your sleep is just to stop all caffeine intake after 12 pm. Unless you seriously overdo it with your morning coffee(s), that should give the body time to process it before it begins to mess with adenosine later at night.

Understand, however, that coffee is not the only beverage to look out for. There’s often caffeine in things like teas, smoothies, soft drinks, sports drinks, and pre workout supplements. These are all likely to affect your sleep too.

Check the label of whatever you take and avoid any caffeinated beverages later in the day. If you work out in the evenings and don’t want to do without your pre-workout, try a product like our stim free pre workout, which is made without caffeine and you get a boost from functional ingredients like beta-alanine, nitrosigine, and more.