Your morning cup of coffee is a great way to wake up and face the day. When you start to fade in the afternoon a cup of coffee keeps you going. And, if you need to drive though the night, repeated cups of coffee keep you going. But how does coffee keep you awake? And what do you do if you want to sleep and too much coffee is not letting you rest so that you need more and more coffee to stay awake during the day? It is the caffeine in coffee that does this.
How Does Caffeine Work?
The caffeine in your coffee absorbs into your body very quickly after you drink your coffee. And it goes everywhere in your system including your brain. In your brain is where caffeine blocks adenosine receptors. These chemical receptors are what promote sleep when we are tired at the end of a long day or any time. It turns out that caffeine is chemically configured much like the adenosine molecule, so it easily latches on to the sleep-promoting receptors and work at cross purposes with adenosine.
What Does Adenosine Do?
The adenosine molecule helps regulate your circadian cycle, the waking, sleeping cycle. When it binds to the adenosine receptors in the brain it triggers various nerve pathways that increase the feeling of sleepiness and slows neural activity. Normally, adenosine levels are low in the morning when we are waking up and increase gradually during the day. After several hours adenosine begins the process of making you feel sleepy. You go to bed and to sleep and the process begins again the next day.
How Caffeine Confuses the Adenosine Sleep Cycle
Although caffeine binds to adenosine receptors it only blocks them and does not trigger all the natural processes that adenosine does. Luckily for your ability to sleep, caffeine does not bind to adenosine receptors permanently. As the level of caffeine in your body diminishes so does its level of attachment to adenosine receptors in the brain. The half-life of caffeine after you drink it is somewhere between four and six hours. That is, every four to six hours the level of caffeine in your body drops by half. That is why when you have a strong cup of espresso with supper you may be awake after midnight. As a rule, do not drink any coffee or other drinks with caffeine after two or three in the afternoon and you will not have enough on board to interfere with adenosine attachment to brain receptors and your sleep at night.
How Much Coffee Interferes with Sleep?
The odds are that your morning cup of coffee will not interfere with your sleep at night. But, if you drink up to six cups of coffee a day, which level of consumption comes with several useful benefits like reducing your risk of type II diabetes, it might be a different matter. In addition, it is important how late in the day you drink your last cup of Java. If you don’t drink coffee after noon, you will have a fourth as much caffeine or even an eighth as much in your system by the time you want to sleep. Even though you may not be aware of it, too much coffee on board can affect how well you sleep, and the level of caffeine needed to interfere with sleep varies from person to person. So, drink coffee if you need to stay awake but be aware that consuming too much caffeine too late in the day keeps you awake at night and makes you tired the next day.