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How Does Caffeine Affect Sleep? Facts & Expert Tips

sleepless woman in bed

After a sleepless night, it is normal to reach for a hot cup of coffee to help you wake up and face your day. Throughout that day, when the coffee seems to be wearing off a bit, having another cup, grabbing a cold soda, or downing an energy drink can keep us going even when we feel tired. The pep we feel in our steps after having one of these beverages is thanks to the caffeine found inside. But, did you know those same drinks, and the caffeine we depend on, could be the reason for your sleepless night in the first place?

Caffeine is a stimulant that affects our central nervous system. It also makes us feel more alert, enhances our mood, and fights the sleep-promoting chemical adenosine. Since this is the job of caffeine, and the reason many people choose caffeinated beverages to get through their day, simply avoiding caffeine before bedtime should do the trick and fend off sleepless nights, right? Wrong. Unfortunately, caffeine has more of an effect on your sleep patterns than you realize. We’re going to take a look at how caffeine affects sleep so you can better understand the relationship and change your habits for a better night’s sleep.

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Caffeine and Falling Asleep

As we mentioned above, caffeine blocks adenosine. While we are awake, and going through our day, our brains naturally produce adenosine. The longer we are awake, the more adenosine we produce. This chemical is what makes us feel tired and sleepy. When we consume caffeine, in any form, that tired feeling fades thanks to the stimulant’s effects on our brains and how it binds to adenosine receptors. But that’s not the only thing caffeine affects when it comes to sleep.

Have you ever talked about your internal sleep clock? For most of us, it’s how we describe our body’s ability to fall asleep at certain times and even wake up without the use of an alarm clock. The technical term is circadian melatonin rhythms. According to certain studies, having caffeine before bed can interrupt your internal sleep clock and keep you from falling asleep when your cycle calls for it. You’ll also find that the same studies believe your morning cup of coffee or dose of caffeine can restart your clock for your new day ahead.

a hand of a woman holding a cup of coffee
Image Credit: Engin_Akyurt, Pixabay

Caffeine and a Restful Night’s Sleep

Naturally, if caffeine can keep you awake, it can affect how restful your sleep is. Slow-wave sleep is the refreshing, deep sleep our bodies need to wake feeling rested. With lots of caffeine in your system, this wave of sleep can be impacted and pushed back. If you enjoy an energy drink on the way home from work at 6 p.m. you may find yourself unable to fall into a restful sleep until midnight or later.

These effects are often attributed to caffeine’s half-life or the amount of time it takes your body to metabolize half the caffeine you’ve consumed. According to The National Library of Medicine, caffeine’s half-life is 5 hours. This means when you enjoy a caffeinated beverage later in the afternoon, you’ll still be feeling some of the stimulation from your drink 5 hours later hence the possibility of sleep disruptions.

Other Factors to Consider

As you can see, there’s no doubt that caffeine intake may affect your sleep cycle, but why doesn’t it happen to everyone? Do you know someone who can sit and drink a soda before falling asleep? This is due to everyone’s bodies being different. While caffeine may hype you up and give you the jitters, your best friend may have a higher tolerance and enjoys their caffeine later into the evening hours without issues.

Caffeine sensitivity or tolerance, age, weight, and genetics all come into play when determining how caffeine will affect your body. The most important thing to remember is to pay attention to what your body is telling you. If you drink caffeine late in the day and find it hard to fall asleep at night, cut the caffeine out of your afternoons. This may help you fall asleep earlier and sleep better.

woman drinking coffee
Image Credit: Chait Goli, Pexels

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Final Thoughts

Caffeine may be our go-to for staying alert and navigating through our day, but it’s not the friend you want around when the evening hours approach. If you want to get a good night’s sleep you should avoid excessive caffeine later in the day. Your body will thank you for the rest. Besides, your coffee will be waiting for you when you wake up refreshed the next morning.

Featured Image Credit: Kinga Cichewicz, Unsplash


Melissa Gunter

Melissa has been a fan of coffee since the first sip she stole from her Granny's cup when she was just a girl. Now, she spends each morning writing with a hot cup of coffee at her side. With a love of sweet and creamy bliss, Melissa and her daughter, Amber, stop by and try out every local coffee shop they see. Neither are afraid to try something new and have a long list of favorite coffee beverages they simply can't do without. When she's not freelance writing about her 2 passions, coffee, and pets, Melissa spends her time with her husband, 2 kids, and 5 fur babies. She also loves diving into the fiction world under her pen name, Rena Marin. If she isn't at the laptop or with the family, Melissa is out enjoying the mountains of East Tennessee she calls home.

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