Whether black and bitter or creamy and sweet, a cup of coffee is on the morning menu of millions of people every day. America's love of coffee and the global appeal of tea make caffeine the most widely used drug in the world. When you use any substance that causes physical dependence, such as caffeine, it's wise to educate yourself about the ways it affects your body.
Energy Levels
Caffeine has been found to delay fatigue normally experienced during exercise. Dr. J. M. Davis of the Department of Exercise Science at the Universe of South Carolina attributes this to its influence on the central nervous system. Davis' research, published in the February 2003 issue of the American Journal of Physiology, studied caffeine's effects on adenosine receptors in the central nervous system and concluded that caffeine blocks these receptors. Adenosine normally attaches to central nervous system receptors and reduces the activity of brain cells, causing sleepiness. When caffeine takes its place by blocking the adenosine receptors, brain cells remain active and you feel more awake.
Cognitive Performance
A popular advertising campaign in the 1980s urged consumers to become "coffee achievers." Much to the chagrin of purveyors of caffeinated products, caffeine has not demonstrated the ability to improve cognitive performance. Peter Rogers, of the Department of Experimental Psychology at the University of Bristol, studied the effects of caffeine, and withdrawal from it, on the cognitive performances of tea and coffee drinkers. His research, published in the journal Psychopharmacology in June 2005, found that caffeine is only helpful in improving cognition in those who are undergoing caffeine withdrawal. Even sleep-deprived subjects gained no cognitive benefits from caffeine, unless they were also undergoing withdrawal from the drug.
Physical Effects
Caffeine is known to affect your health in both mental and physical ways. According to Drugs.com, adverse reactions of the central nervous system to caffeine include muscle tremors, insomnia, headache, tinnitus and a condition known as scintillating scotoma, which describes the presence of visual disturbances prior to migraine. By blocking adenosine receptors, caffeine also influences the release of adrenaline, a hormone that increases heart rate, blood pressure and blood glucose, according to the Smith College Sophian.
References
- Smith College Sophian: Caffeine: Energy Booster or Addictive Drug?
- PubMed: Effects of Caffeine and Caffeine Withdrawal on Mood and Cognitive Performance Degraded by Sleep Restriction.
- Drugs.com: Caffeine
- KidsHealth: Caffeine
- PubMed: Central Nervous System Effects of Caffeine and Adenosine on Fatigue
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