Sleep and Caffeine
Of the multitude of factors that affect the quantity and quality of sleep, caffeine intake is one that merits serious discussion. The effects of caffeine on sleep have been well studied and we also know many of the underlying mechanisms behind caffeine’s biological effects. While caffeine has been hailed as an effective “pick me up” that helps to provide a sudden surge of mental vigor and alertness, it has also been called as an addictive drug by many. This colorless, flavorless chemical substance is present in a variety of natural and artificial foods and food products. Coffee beans, teal leaves and cocoa nuts constitute some natural sources of caffeine. Caffeine is also found in most cola brands.
Coffee, a typical cup of which contains around 75mg of caffeine, is the drink that has been used traditionally by those who want to stay awake during the night. The effects are attributed mainly to caffeine.
Scientific studies have pointed out that caffeine intake is associated with sleep disturbances and sleep deprivation. In short, caffeine can cause insomnia, leading to delay in falling asleep and considerable shortening of the sleeping time. However, the influence of caffeine on sleep depends on the amount of caffeine consumed. Moderate consumption of caffeine, (around or less than 250 milligrams daily) does not, in most people, cause any significant sleep problems. Consumption levels of more than 300mg per day points to caffeine addiction and such “caffeine addicts” may develop sleep problems that can even become chronic in nature.
At least some of the mechanisms underlying caffeine’s sleep delaying activity have been illustrated.
Caffeine is known to cause constriction of blood vessels supplying blood to the brain. The reduced blood supply to the brain does not allow either the brain or the body to reach a sleep state. Caffeine also triggers the release of a hormone called adrenaline that has the property of imparting a heightened wakefulness (or alertness) to the person. Also, caffeine has a mild stimulatory effect on the heart and therefore serves to increase the heart rate. Increased heart rate is not helpful to attaining sleepiness.
There is yet another mechanism that is believed to contribute to insomnia caused by caffeine. Caffeine, by increasing blood flow through the kidneys, acts as a diuretic. If a person takes caffeine rich drink such as coffee prior to going to bed, then his sleep can be disturbed in the night by a full bladder and the urgency to urinate.
Lastly, the time of intake of the caffeinated drink plays an important role in determining its effects on sleep. Caffeine, following ingestion, crosses over into the blood stream and reaches peak blood levels after approximately an hour. Therefore, for those who are coffee addicts, and who simply cannot do away with caffeine, care should be taken to stop coffee consumption at least a couple of hours before the intended bedtime.
Although coffee (and in essence, caffeine) is generally associated with causing insomnia, in a minority of people, especially in coffee addicts, having a cup of coffee a couple of hours before going to bed can actually work to induce sleep. This is attributed to some of the delayed-relaxing effects of caffeine.
If caffeine consumers want to make sure that their coffee doesn’t make them lose their sleep, then it is advisable to make sure that they limit their caffeine intake and to have last cup of coffee at least a couple of hours before bedtime!
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