Millions of us couldn’t survive without our morning cup of coffee, and it is clear that caffeine benefits include improved attentiveness and counteracting the effects of poor sleep. Caffeine is the most commonly used stimulant in the world, but what exactly is it? Moreover, how does it affect our sleep? Caffeine may be familiar, but you may be surprised by what you don’t know about it.
What is Caffeine?
It is estimated that 90 percent of adults in the world consume caffeine in their daily diet. More than 150 million Americans drink coffee on a daily basis. Most drink an average of two cups per day -- the equivalent of about 270 mg of caffeine. In the developing world, tea is the preferred method of caffeine intake. Interestingly, tea is second only to water as the most commonly consumed beverage, and three times as much tea as coffee is drunk in the world.
Caffeine is a stimulant. It works on the nervous system at the site of a neurotransmitter called adenosine. This results in excitation, which can have varied effects on the body.
Commonly Consumed Foods that Contain Caffeine
There are many types of foods and beverages that contain differing amounts of caffeine. Some of the most common, with the amount of caffeine per serving noted parenthetically, include:
- Brewed coffee (135 mg)
- Drip coffee (112 mg)
- Instant coffee (66 mg)
- Espresso (35 mg)
- Latte (35 mg)
- Cappuccino (25-60 mg)
- Starbucks coffee, short (250 mg)
- Tea (35 mg)
- Cocoa (5 mg)
- Chocolate bar (10 mg)
- Dark chocolate bar (31 mg)
- Cola (46 mg)
Benefits of Caffeine
The precise effect of caffeine is dependent on numerous factors, including your own tolerance as well as how much you drink. In general, caffeine increases short-term mental alertness, energy, and the ability to concentrate. It is particularly effective in people who work at night. Athletic performance can also be enhanced by the use of caffeine.
Caffeine and Sleep
Caffeine use may also have adverse effects, and may be disruptive to your sleep. Therefore, guidelines for better sleep recommend that caffeine not be consumed within six hours of going to bed.
Caffeine is the most commonly used stimulant in the world, and as such, it may be helpful to counteract the effects of excessive daytime sleepiness. For millions of us, it serves as a needed boost to get us through the day.
Burke, LM. "Caffeine and sports performance." Appl Physiol Nutr Metab. 2008; 33:1319.
Childs, E et al. "Subjective, behavioral, and physiological effects of acute caffeine in light, nondependent caffeine users." Psychopharmacology. 2006; 185:514.
Fredholm, BB et al. "Actions of caffeine in the brain with special reference to factors that contribute to its widespread use." Pharmacol Rev 1999; 51:83.
Grigg, D. "The worlds of tea and coffee: Patterns of consumption." Geojournal. 2002; 57:283.
Lorist, MM et al. "Influence of caffeine on selective attention in well-rested and fatigue subjects." Psychophysiology. 1994; 31:525.
Smith, A. "Effects of caffeine on human behavior." Food Chem Toxicol. 2002; 40:1243.