The Effects of Caffeine on Sleep

The caffeine in coffee can affect your sleep
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Caffeine is a stimulant most people use to give them energy and to stay alert. A moderate amount of daily caffeine intake is 250 mg which equals approximately 3 cups of coffee. Although it offers no nutritional benefit it is not considered hazardous when consumed moderately. However, caffeine can become a nuisance when you drink too much of it. Since caffeine enters your system through your stomach, you can feel its effects as quickly as 15 minutes after consumption. It stays in your system for many hours and takes approximately six hours for half of the caffeine you consume to be eliminated.

Mild Sleep Disturbance

The major complaint with caffeine is its effects on the sleep cycle. Excessive caffeine consumption can lead to interrupted sleep as can ingesting caffeine too late in the day. Since it takes six hours for caffeine to exit the body, taking more caffeine within that six-hour period extends its stimulatory effects. Mild disruption of sleep can include waking up during the middle of the night with difficulty returning to a restful state.


Sometimes caffeine can have more persistent effects on your sleep cycle. People who consume more than 250 mg of caffeine per day are usually ingesting more than they can excrete. An overly stimulated central nervous system is one that is producing adrenaline which is a wakeful hormone. This excited state can have long-term repercussions on the sleep cycle and chronic insomnia can set in. Chronic insomnia includes being unable to fall asleep, to stay asleep or to have a restful sleep and can cause daytime sleepiness, difficulty concentrating and irritability.


A side effect of caffeine consumption is polyuria, otherwise known as excessive urination. According to the National Institutes of Health, adults who release more than 2.5 liters of urine per day suffer from polyuria. Not only is caffeine a diuretic, its excitatory effect on the central nervous system can also have an effect on the bladder. Frequent urination can also be disruptive to your sleep cycles.