It’s widely known that consuming caffeine before bed can interfere with sleep. Despite this, many of us find ourselves sneaking in that extra coffee to get us through the final hours of a long work day — only to end up unable to fall asleep later when we finally get home.

If you’re struggling with fatigue during the day, a quick caffeine boost can seem like the perfect solution: and sometimes it is! We often hear about the negative side effects of caffeine, but caffeine can actually offer various health benefits when consumed in moderation. Here, we’ll discuss that and explore the effects caffeine can have on your sleep.

What is caffeine?

Caffeine is a natural stimulant that is found in coffee beans, cacao beans, tea leaves, and various other plant species. It is often added to energy drinks and other soft drinks.

Humans have been consuming caffeine for thousands of years, but it wasn’t until 1819 that the first ever isolation of caffeine occurred. That was thanks to German scientist, Friedlieb Ferdinand Runge, who was able to isolate the stimulant from coffee beans during an experiment.

Today, caffeine is one of the most widely consumed active food ingredients in the world. In fact, a 2020 survey from the Coffee Association of Canada found that 71% of Canadians had consumed coffee — one of the most popular sources of caffeine — in the day prior to being surveyed.

What does caffeine do to your body?

Scientists continue to study caffeine to learn more about its effects on us, both positive and negative. Current research has given us a better understanding of this natural stimulant and how it interacts with our bodies.

When you consume caffeine, your gut absorbs it very quickly and it enters your bloodstream. It then travels to your liver, where it’s broken down into compounds. Although caffeine can impact the function of various organs, its main effects are felt by the brain.

Adenosine is a neurotransmitter that relaxes your brain and makes you feel tired. Your brain naturally produces adenosine and normally, levels build throughout the day, preparing you for sleep. When you consume caffeine, its compounds connect to adenosine receptors in your brain without activating them — this blocks the effects of adenosine, which leads to reduced tiredness.

Research suggests that consuming caffeine may also elevate adrenaline levels and increase brain activity of dopamine (a chemical which plays a role in how we feel pleasure) and norepinephrine (which increases your heart rate and makes your heart pump blood at a higher rate). These effects combined stimulate your brain, encouraging alertness and heightening focus.

Does caffeine have health benefits?

In addition to raising your energy levels, research has shown that caffeine may improve cognitive function when consumed in low to moderate doses. Caffeine can improve your physical performance in the short-term and because it has been shown to raise resting metabolic rates, it can also help your body burn fat — that’s why you often see caffeine as an ingredient in dietary supplements.

In the long-term, caffeine is believed to reduce your risk of type 2 diabetes and studies have indicated a link between drinking coffee and a lowered risk of Parkinson’s disease. Some research suggests that drinking coffee can also protect against cirrhosis (scarring of the liver) and that it may even reduce the risk of liver cancer.

If you get your caffeine fix from coffee, you’re not only getting the benefits of caffeine — coffee is rich in antioxidants, which can neutralize harmful free radicals and protect against aging.

While caffeine can offer many health benefits, it’s important to keep an eye on your consumption. The FDA states that healthy adults should be able to consume up to 400mg of caffeine per day without experiencing negative side effects (for reference, one cup of homebrewed coffee contains 95mg of caffeine on average). However, it’s important to note that everyone reacts to caffeine differently. Those who are pregnant or have underlying health conditions should speak with their healthcare provider to determine how much caffeine they can safely consume.

How does caffeine affect sleep?

Because of caffeine’s stimulatory effects on the brain, consuming it too close to bedtime can interfere with your sleep schedule and decrease the quality of your sleep.

In a study which examined the effects of caffeine on sleep, participants were administered a 200mg dose of caffeine three hours prior to bedtime. This was found to reduce sleep efficiency (the ratio of total sleep time to time in bed), decrease overall sleep time, and increase the amount of time it took for participants to fall asleep.

Another 2013 study found that even when consumed six hours before bed, caffeine more than doubled the time it took for subjects to drift off. The same study noted that caffeine can also affect sleep architecture, lowering the time people spent in Stage 1 and Stage 2 sleep.

It’s clear that there are long-term benefits to moderate caffeine consumption in addition to the temporary energy boost this natural stimulant can provide. However, consuming too much caffeine (or consuming caffeine late in the day) can wreak havoc with your sleep schedule and lead to unpleasant and potentially harmful side effects.

If you feel your caffeine intake is causing problems with your sleep, it’s worth considering cutting back or saving caffeinated beverages and foods for earlier in the day. If you do decide to reduce your caffeine consumption, do so gradually to avoid withdrawal symptoms like irritability and headaches.

By itself, caffeine has no taste and no nutritional value: but it’s present in many food products, drinks, and even medications. Be mindful of this if you’re monitoring your caffeine intake: always check ingredients labels for the presence of caffeine or opt for caffeine-free alternatives if you’re unsure whether a product contains caffeine.