Welcome to part 3 of our Better Sleep series. We’ve already covered the importance of sticking to a daily sleep schedule and finding the right time to exercise to optimize your sleep. Now we’re talking about stimulants, specifically caffeine and nicotine.

Caffeine and nicotine are both stimulants, so it’s no surprise they can affect your sleep. But how much do they actually disturb your nighttime sleep? Surely a cup of coffee in the morning can’t alter your sleep cycle, right? And cigarettes help you relax, so how would that damage sleep?

Those are both valid questions … with complicated answers. So, let’s dive in and start with everyone’s favorite psychoactive stimulant: caffeine.

How Caffeine Works

Yep, that’s right. Caffeine is not a dietary supplement; It is the most used psychoactive stimulant in the world. I know that sounds a little harsh, but I’m just calling it what it is. And that doesn’t make me love Dr. Pepper any less.

As a psychoactive stimulant, caffeine doesn’t make you more awake and alert; it tricks your brain into thinking it’s more awake and alert. And it all starts with adenosine.

Adenosine is a chemical that’s present in all human cells. According to News Medical, “In the brain, adenosine is an inhibitory neurotransmitter. This means, adenosine can act as a central nervous system depressant. In normal conditions, it promotes sleep and suppresses arousal. When awake the levels of adenosine in the brain rise each hour.”

Did that explanation put everyone to sleep? Yeah, that’s what I thought.

So, here’s the translation: Adenosine is a chemical naturally occurring in your body that makes you tired. Throughout the day, your adenosine levels rise, which makes your body ready for sleep at bedtime.

Here’s where caffeine comes in. Caffeine fights with adenosine and actually blocks the adenosine receptors in the brain, acting as a masking agent. So, instead of getting sleepy, your brain thinks it’s ready to party.

Thirty minutes after taking caffeine, you hit your peak alertness. But caffeine stays in your system much longer than that.

Half-Life

When I hear the term “half-life,” I usually think about fossils and carbon dating. But all elements have a half-life, including caffeine. So, what is half-life?

Half-life is the amount of time it takes for half of the quantity of a substance to be reduced to 50% of the original amount. While carbon’s half-life is thousands of years (5,730 years, to be exact), caffeine’s half-life is 5-7 hours.

If you’re thinking in carbon terms, a half-life of 5-7 hours seems really short. But to your body, 5-7 hours can be a long time.

For example, if you have coffee after dinner at 9 pm, the caffeine is still active in your body and circulating in your brain tissue at 1 am. So, even though the initial effects of the caffeine have worn off by 1 am, 50% of that caffeine is still in your system, keeping you from sleep. And it will take another 5-7 hours for the original caffeine to reduce to 25%.

Caffeine and Sleep

While that cup of coffee after dinner is enticing, it will prevent you from falling asleep easily and having a sound sleep. Even if you are able to fall asleep, your body will still be fighting against the caffeine, making for a rough night’s sleep.

If you happen to stay awake through the effects of the caffeine, you’re likely to experience the “caffeine crash.” This happens when the caffeine wears off and you suddenly have a huge to sleep.

Here’s why that happens: While caffeine is blocking the adenosine receptors in your brain, adenosine is still building up. So, when your liver rids your body of the caffeine, all the adenosine rushes in, causing you to be more tired than you were before.

Some people choose to fight the caffeine crash with more caffeine, and the cycle starts all over again.

Excessive caffeine consumption (more than 500 mg a day) is not healthy and can come with some serious health consequences, including insomnia. But we also know that caffeine is sometimes necessary. So, if you don’t want caffeine to ruin your sleep, don’t exceed 500 mg a day and avoid having your cup of coffee or Coke later in the day.

How Nicotine Works

We can all agree that nicotine is bad for you, right? That smoking, specifically, is the leading cause of preventable disease in the US and increases the risk of heart attack, stroke, and cancer? Ok, good. Now we can move on.

The interesting thing about nicotine is that it can have almost the opposite effect on your mind and body depending on why you’re taking it.

“Nicotine has a stimulating effect, but it also has an overall mood-modulating effect,” says Amanda Holm, M.P.H., tobacco treatment manager at Henry Ford Health System. “If you’re bored, sleepy or tired, nicotine will act as a stimulant to help you feel more alert and awake. But, if you’re feeling anxious, it will smooth out your anxieties. If smoking helps keep you on an even keel throughout the day, that can become a problem after you quit.”

So, whether you need a little pick me up or something to calm you down, nicotine can help with both.

Nicotine and Sleep

Studies have shown that people who consume nicotine are more likely to suffer from insomnia. That includes increased sleep latency (it takes you longer to fall asleep), sleep fragmentation (interrupted sleep), and decreased slow-wave sleep (less restorative sleep). All of this, of course, leads to daytime sleepiness, which then makes you want to have another cigarette. It’s a vicious cycle.

Smokers also have an increased risk of sleep-related respiratory disorders. As you can imagine, that also worsens sleep quality and increases daytime sleepiness.

And let’s not forget about nicotine withdrawals. For regular smokers, their body craves nicotine even when they’re asleep. Which means the nicotine will cause them to wake up early in the morning to get their nicotine fix, causing them to get even less sleep.

The bottom line: nicotine is a bad deal. If you’re a smoker and have considered quitting, today might just be the day. Your body and brain will thank you.

Caffeine has become a staple in our culture; it gets us up in the morning and keeps us going throughout the day. But even if you have caffeine every day, it doesn’t mean you have to have terrible sleep. It just means you have to be aware of when and how much caffeine you consume. For our nicotine users, the best way to improve your sleep is to stop using nicotine. Sorry.

Want more tips on how to improve your sleep? First, get yourself an awesome pillow, then check out our other posts about sleep schedules (include link to post) and how exercise affects your sleep (include link to post). Next time we’ll be talking about alcohol. Stay tuned!