For many of us, a cup of coffee feels like a necessary part of our morning routines. The caffeine, found naturally in a wide range of plants like the coffee plant and tea plant, can help us wake up, give us an extra boost of energy in the middle of the day and even help improve our mood. But this isn’t without potential side effects, including less good-quality sleep.

How does caffeine work?

As a stimulant, caffeine increases the circulation of chemicals like cortisol and adrenaline throughout your body and increases activity in your brain and nervous system. Within 5 to 30 minutes, it can increase your energy, mental alertness, heart rate and breathing. Depending on the person and amount taken, these effects can last up to 12 hours, but it can also cause a wide range of side effects like anxiety, headaches and sleeplessness.

The effects of caffeine on sleep

Most often, we drink coffee (or consume caffeine in other ways) because we’re tired. But in doing so we could actually be making the issue worse. This is because caffeine can negatively impact our sleep in a variety of ways.

Not only can it make you fall asleep later, but it can also reduce the quality and length of sleep, leaving you feeling less refreshed the next day. These effects can still occur even if it’s consumed long before bedtime. One study found that having caffeine as early as 6 hours before bed could reduce total sleep time by 41 minutes, but the most consistent effects were noticed when it was consumed 3 hours before sleep.

So, if caffeine is part of the reason we feel tired, but it helps us feel more awake the next day, it’s no surprise that it can be a difficult cycle to break.

How much caffeine is okay?

The knowledge that caffeine might be negatively impacting our sleep and health in other ways isn’t necessarily going to stop us from consuming it. So, how much caffeine is actually okay to have? This depends on the individual person, but dangerous side effects are generally not associated with 400 milligrams (roughly four or five cups of coffee) or less a day.

However, some people are more sensitive to caffeine and if you notice side effects like anxiousness, jitters, or an upset stomach, even before you’ve had the recommended maximum amount, it’s best to stop. Children and adolescents should be discouraged from caffeine consumption, and if you’re pregnant, breastfeeding or have any health conditions that are of concern, you should also get advice from your doctor.

To reduce its impact on your quality of sleep, you should also stop consuming caffeine at least eight hours before bed, as it can take some time for the effects to wear off.

Other factors that impact sleep