Did you know that caffeine can keep you from sleeping -- and keep you from resting well even if you do fall asleep?
Getting a good night’s sleep is an important part of a balanced and healthy lifestyle. It’s essential because it allows our bodies to recharge. That’s why having a non-restful night or broken sleep can have negative health effects including mood swings, not being alert during the day and weight gain due to the added stress hormones and their effect on insulin.
Caffeine is a stimulant that enters the bloodstream, through the stomach and small intestine, shortly after consumption. The stimulating effect of caffeine can sometimes take no longer than 15 minutes after consumption to set in.
Caffeine's effect on sleep can be seen in the transition through the entire sleep cycle. Basically, some parts of the sleep cycle that are affected are as follows:
1.Increased sleep latency (time it takes to fall asleep)
2.Shorter total sleep time
3.Increase in the “light sleep” total time
4.Decrease in the “deep sleep” total time
5.More frequent awakenings throughout the night
Many studies have demonstrated the effect of caffeine on sleep. Consistently, these studies prove that higher caffeine consumption leads to a decrease in sleep time and overall sleep quality.
Looking at 2 different studies, one from the Institute for Scientific Information on Coffee, and a survey from StatCrunch, we can understand caffeine's effect on sleep, both in the adolescent and adult population.
The first study found that approximately 33% of teenagers have fallen asleep during school. Caffeine consumption of these teenagers was about 76% higher than those who did not fall asleep during school.
The second study, a survey of 108 adults, found that a majority do not have a single night during the week when they get 8 or more hours of sleep. Many of these people had at least one caffeinated beverage throughout their day.
What is caffeine's half life and how does this affect sleep quality?
The half life of caffeine in your body is about six hours. That means that if you consume a big cup of coffee with 200 milligrams of caffeine at 3 p.m., for example, about 100 milligrams is still in your system at 9 p.m. when your body should be powering down for the evening.
How does caffeine interfere with the stages of sleep?
You may experience increased fatigue because you don't reach stage four rapid-eye-movement sleep. Stage four is your deepest level of sleep during which your body repairs and renews itself for the next day. This is also when you processes emotions. You may experience severe physical and emotional symptoms after years or even decades of not getting enough stage four sleep. Some people don’t realize that caffeine’s effect on their sleep is causing many of their medical issues.
Why do I crave caffeine first thing in the morning?
Overnight is the longest a habitual caffeine user goes without caffeine, so it makes sense that you’d want some in the morning. This is why many users feel more of a buzz after their first drink of the day. A study from John Hopkins University found that avoidance of caffeine withdrawal symptoms motivates regular use of caffeine. For example, the study states, the satisfying feelings and perceived benefits that many coffee users get from their morning coffee appears to be a simple reversal of the negative effects of caffeine withdrawal after overnight abstinence.
What is it about caffeine that makes me unable to sleep?
Caffeine releases stress hormones, increases heart rate, raises blood pressure and does many other things to stimulate your system. It also releases adenosine into the brain, blocking the signal that the body sends throughout itself readying you for sleep.
I usually fall asleep just fine, but why do I wake up throughout the night?
There could be many reasons for this, of course, but you should consider elevated stress hormone levels from caffeine as a potential cause. Years of caffeine use can dramatically affect your adrenal glands, the mechanisms responsible for the production of stress hormones. Having abnormal levels of stress hormone levels -- including high levels of adrenaline and cortisol -- can cause a variety of symptoms, including fatigue, lack of motivation and decreased quality of sleep.
How does caffeine’s role in sleep negatively affect natural energy levels?
Caffeine is an artificial stimulant that can dramatically impact sleep quality after both short-term and prolonged use. When you’re not getting enough quality sleep, you feel tired and often reach for even more caffeine, especially in the mornings. This can become a vicious cycle as the effects of caffeine become less and less satisfying over the years. This, in turn, can lead to a downward spiral of symptoms, including a detrimental effect on your natural energy levels.
Is there a name for caffeine's negative effect on sleep?
Yes. Caffeine-induced sleep disorder is a psychiatric disorder that results from over-consumption of the stimulant caffeine. When caffeine is consumed immediately before bedtime or continuously throughout the day, psychiatrists say in their published literature, sleep onset may be delayed, total sleep time reduced, normal stages of sleep altered, and the quality of sleep decreased.
Caffeine and Daytime Sleepiness: The Cycle
Many people ingest caffeine throughout the day in order to alleviate their daytime sleepiness. In fact, approximately 43% of Americans used caffeine to combat daytime sleepiness, according to a Sleep in America poll. This was in 2001. Since then, many more people have fallen into this habit. While these people may believe that this solves their problem, it actually makes it worse.
Once again, caffeine has a half life of 6 hours. This means that it takes 6 full hours for just half of the caffeine consumed to work its way out of the body. Therefore, any amount of caffeine ingested during the day will most likely affect the amount of sleep and sleep quality received during the night.
To summarize, there is a cycle that exists between caffeine and sleep. People ingest caffeine during the day to get rid of daytime sleepiness. However, the daytime sleepiness occurs because not enough sleep, or low quality sleep, happens during the night, due to the caffeine content that still persists in the system.
Therefore, the only way to truly alleviate sleepiness is not by temporary caffeine rushes, but by eliminating caffeine from the diet altogether.
Caffeine and sleep correlate. The less caffeine people consume, the more sleep they will receive.
Caffeine and Sleep. Institute for Scientific Information on Coffee. Retrieved from