June 27, 2018

Let's do a thought experiment. Imagine it's Monday morning. You hear the familiar (and unwelcome!) beeping of your alarm, slowly open your eyes, and lie in bed for a few minutes while you wake up. Finally, you groggily pull yourself up and get dressed while trying to mentally prepare for another start of the workweek. You walk to the kitchen for breakfast. What is the first thing you reach for?

If it's a cup of coffee or tea, you're not alone. In fact, more than 80% of North American adults use caffeine on a regular basis - and Canada is leading the pack! In 2015, a study conducted by Euromonitor found that Canadians have the third-highest coffee consumption per capita in the world (just behind Finland and the Netherlands), with a staggering 152.1 litres per person per year! This should come as no surprise, of course, when you consider that phrases like "making a Tim's run for some double-doubles" are a regular part of our vocabulary! 

But what is all of that caffeine doing to our sleep schedules? Read on to find out what caffeine is, how much is safe to take, how it affects your sleep cycle, and ways to improve the quality of your sleep without having to ditch your daily cup of joe!

What Is Caffeine?

Simply put, caffeine is the most widely used and popular drug in the world. It's a naturally occurring stimulant found in coffee beans, tea leaves, cocoa beans, guarana and yerba maté. Like other stimulants, caffeine makes you feel more alert, increases your heart rate, and can have a positive effect on your mood and mental performance - to a point. If you're getting too much, it can cause sleep issues, anxiety, and heart problems.

Caffeine is a fast-acting stimulant, with its effects being felt within about 5 minutes. It reaches its peak effect in about 30 minutes, but takes 4 or 5 hours to be fully metabolized depending on a variety of factors including your body weight and how much food you've eaten.

How Much Caffeine Is Safe?

Like all stimulants, caffeine use needs to be managed. It is an addictive substance that comes with withdrawal symptoms like headaches, fatigue, or anxiety when we cut back. Too much caffeine is also dangerous and can lead to heart palpitations, anxiety, high blood pressure, and insomnia. We're all familiar with the jitters that happen when we've had too much coffee in a day!

Based on the recommendations from Health Canada, the average adult can consume up to 400mg of caffeine per day (about three 8-ounce cups of brewed coffee) with no ill effects. Unfortunately, nearly 1 in 5 Canadians gets more than the recommended daily maximum! Most of us drink our caffeine, but it is also found in some common foods like ice cream, frozen yogurt, and even some breakfast cereals. To make matters more complicated, there are no regulations in place for Canadians to tell which foods have caffeine in them and which ones don't. If it is naturally-occuring in the ingredients of the product and the caffeine isn't added alone, it doesn't even have to be listed on the label!

To give you an idea of the amount of caffeine you're taking in every day, check out the chart below. How does your consumption stack up to the recommendations?

Product Volume Caffeine Content (approximate in mg)
Coffee (brewed) 8 oz (237ml) 135
Espresso 1 oz (30ml) 55
Black tea 8 oz (237ml) 50
Green tea 8oz (237ml) 30
Cola, regular 12 oz (355ml) or 1 can 41
Cola, diet 12 oz (355ml) or 1 can 45
Energy drink 8 oz (237ml) 27-164 or more (see label)
Energy shot 1 oz (30ml) 40-100 or more (see label)
Baking chocolate (unsweetened) 1 oz (28g) 25-58
Milk chocolate candy bar 1 oz (28g) 7
Chocolate cake 2.8 oz (80g) 36

It's important to remember that many energy drinks get extra caffeine from ingredients like guarana and yerba maté. Because the caffeine is naturally found in those ingredients, it doesn't need to be listed separately on the label according to regulations. If your energy drink has either of those ingredients, it's safe to assume that it contains even more caffeine than is listed on the label! Drink them at your own risk!

How Does Caffeine Affect Your Sleep?

Anyone who drinks coffee knows that it can help you wake up or keep you alert during a tiring day. This is great first thing in the morning when you need a boost to get going, but not so great as the day wears on and your body starts preparing for sleep. Too much caffeine during the day can make you take longer to fall asleep, reduce the quality of your sleep, and increase the sleepiness you feel the next day. There are a couple of reasons for this:

  • Caffeine blocks adenosine. Adenosine is a neurotransmitter that builds up in your body during the day, making you feel less alert and more sleepy as time goes on. Caffeine looks just like adenosine to your brain, but acts in essentially the opposite way. As a result, it tricks your brain into thinking it's already used the adenosine to make you sleepy and makes it harder for you to fall asleep at night.
  • Caffeine inhibits melatonin production. You might be surprised to learn that caffeine has an even greater effect on your circadian rhythm than bright light! When you drink coffee, the caffeine counteracts the effects of melatonin on your alertness levels and makes you feel awake long past when your body should be winding down.

In 2013, researchers published a study in the Journal of Clinical Sleep Medicine that examined the effects of a 400mg dose of caffeine taken at different times of the day. They found that caffeine taken even 6 hours before bedtime still had a significant effect on the subjects' sleep duration and sleep quality - way past the time when the participants felt the effects of the caffeine!In fact, they found that participants who took caffeine 6 hours before bedtime slept on average a full hour less than people who had no caffeine. As a result, the researchers suggest stopping your caffeine intake long before it's time for sleep - 6 hours at an absolute minimum.

How To Drink Coffee And Sleep At Night

Don't worry. You don't have to say goodbye to your prized morning coffee if you still want to sleep at night - in fact, caffeine in reasonable doses can lead to big benefits in your alertness, mood, and mental performance! The trick is to enjoy your caffeine in moderation, and at the right time of day. Here are a few simple guidelines to follow to keep your sleep schedule in check:

  • Don't exceed 400mg of caffeine per day. Anything beyond that can lead to problems. In fact, some studies have linked overconsumption of caffeine to higher mortality rates in both men and women. Just don't do it!
  • Ditch the monster-sized drinks. Many coffee chains offer drinks in 12, 16, or even 24 ounce sizes! While it's tempting to go for the larger option, it's better to regulate your caffeine intake by drinking out of smaller cups. With 135mg of caffeine in 8 ounces of coffee, even two 16-ounce cups in a day will exceed the recommended daily dose of caffeine. 
  • Taper your caffeine consumption during the day. Most of us need a bit of a boost in the mornings, and crave our daily caffeine boost. That's totally fine! As the day progresses, you should need less and less caffeine to stay alert. Try swapping out your coffee at lunch with tea or hot chocolate instead, and gradually taper your intake down as the day goes on.
  • Set a cut-off time and stick to it. We recommend stopping all caffeine intake at about 2pm. That way, you'll have at least 6 hours for the caffeine to leave your system before it's time to get ready for bed, plus a couple of extra hours for your body to make you sleepy.