The stimulant chemical caffeine in a morning cup of a coffee is the world's most popular drug, according to the Centre for Addiction and Mental Health in Ontario. Caffeine can temporarily increase the sensation of alertness, but once it wears off, drowsiness may ensue. After the caffeine from a morning cup of coffee is metabolized by midafternoon, you may feel more tired than you would have if you had skipped the coffee.
Caffeine
Chemically, caffeine is a purine alkaloid that is absorbed rapidly into the stomach and small intestine after consumption. It takes effect within five minutes and reaches its peak impact about 30 minutes after consumption. Caffeine raises pulse rate and blood pressure, and it breaks down fat stores in the body for use as fuel, according to Dr. Mark Jenkins of Rice University. After four hours, about half the caffeine from your morning cup of coffee has been metabolized.
Adenosine
Caffeine works by attaching to adenosine receptors in brain cells. Adenosine is a neurotransmitter that signals the brain and neurological system to slow down. By blocking adenosine, caffeine creates a stimulant effect. By raising the body's level of stimulation, however, caffeine also triggers the production of more adenosine as well as cell adaptions that produce more adenosine receptors. The increase in adenosine can make you sleepy unless you consume another cup of coffee to start the cycle once again.
Withdrawal
Caffeine withdrawal symptoms can occur 18 hours after you have consumed the last cup of coffee, so a 6 a.m. cup of coffee can lead to withdrawal symptoms by midnight. Caffeine withdrawal can include headache, fatigue and drowsiness, according to the Linus Pauling Institute, so that morning cup of coffee may well lead to tiredness at night if you do not consume any additional caffeine through the day. Coffee will also not make up for lost sleep, so if caffeine keeps you awake all night, a morning cup may increase temporary feelings of alertness but will not prevent exhaustion from lack of sleep once that dose of caffeine wears off.
Alternatives
Alternatives to coffee can wake you up without leading to excessive tiredness later in the day. Turning on bright lights in your bedroom or morning work space helps your body to feel more alert naturally, according to the Nursing Online Education Database. Eating an apple provides a quick, easily digestible morning pick-me-up. Protein, especially at breakfast, can help provide energy throughout the day. Skipping meals, particularly breakfast, can deplete energy later in the day.
References
- Rice University: SportsMed Web; Caffeine and the Athlete; Mark A. Jenkins, M.D., et al.; November 1995
- Centre for Addiction and Mental Health; Do You Know...Caffeine; 2003
- University of Illinois McKinley Health Center; Caffeine; May 2010
- Nursing Online Education Database; 50 Ways to Boost Your Energy Without Caffeine; July 2008
- "Chicago Reader"; Health: Does Coffee Make You Sleepy?; Roger Downey; May 1990
- Oregon State University Linus Pauling Institute; Coffee; Jane Higdon, Ph.D.; August 2005
Member Comments