Caffeine, the stimulant present in both tea and coffee, features in the daily habits of millions of people. Commonly used as a pick-me-up after a poor night's sleep, caffeine demonstrates psychoactive properties and can provide a boost in energy levels. However, this kick may precede a notable drop in energy.
Caffeine Effects
Found naturally in coffee beans, cocoa beans and tea leaves, caffeine works through its effects on adenosine receptors in the brain. Adenosine, a neurotransmitter, helps balance the brain's function by inducing relaxation and sleepiness. Because of its similar molecular shape, caffeine occupies receptors for this chemical, which results in a feeling of alertness. A secondary effect of this is the activation of the central nervous system and the release of dopamine from the brain and adrenaline from the adrenal glands. This increases alertness, arousal and anxiety, and prepares the body for physical action by dumping sugars into the bloodstream.
After the Buzz
Caffeine demonstrates a reliable and potent effect on alertness levels in the brain. However, like all stimulants, it can cause fatigue when the initial effects have worn off. Sophie Kerszberg, a health writer and a contributor to Smith College's "Sophian" magazine, says that the energy levels of the body increase in line with the increase adrenaline and dopamine release that accompanies the use of caffeine. However, when the effects of the xanthine compound begin to wear off, the reduced levels of these two catecholamines can cause fatigue.
Caffeine Dependency
Regular consumption of coffee and other caffeinated products can have a negative effect on health and result in dependency on stimulants. Paul Chek, a nutritionist and the head of the Chek Institute, estimates the half-life of caffeine as six hours in most people. Several coffees each day can result in a high concentration of caffeine in the bloodstream throughout the day. If the body adjusts to the higher levels of dopamine and adrenaline that the xanthine compound stimulates, then doing without can represent a major challenge. Headaches, poor temper and low energy appear the most common symptoms in people hooked on caffeine.
Expert Insight
Chek believes that caffeine can have a negative effect on health and body composition. He says that caffeine not only masks fatigue during the day, but it can also ruin sleep at night. The effects of the drug on the central nervous system can also disrupt healthy stress responses. Individuals seeking to lose weight may find their efforts hampered if they over-consume caffeine, with the disruptions in blood sugar levels proving an obstacle in doing so.
References
- "How to Eat, Move and Live"; Paul Chek; 2004
- Smith College Sophian: Caffeine
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