Consumers can find caffeine in coffee, tea, colas and chocolate as well as over-the-counter diet pills and stimulants. This mild stimulant can be found naturally in more than 60 plants. The effects of caffeine are dependent on body weight, metabolism and tolerance. People who ingest caffeine regularly develop a tolerance that requires them to consume more overtime to achieve the same results.
Physiological Response
Caffeine affects the central nervous system. According to the National Cancer Institute, it can increase your heart rate, respiratory rate, blood pressure, blood flow, dopamine levels and glucose released by the liver. Additionally, people may experience narrowing of blood vessels as well as a decrease in heart rate and blood flow to the muscles.
Blood Pressure
By drinking two or three cups of coffee, you can ingest enough caffeine to elevate your systolic pressure up to 14mm of mercury (mm Hg) and your diastolic pressure up to 13mm Hg, according to Sheldon G Sheps, M.D. a staff member at the Mayo Clinic. Systolic pressure is the top number and diastolic pressure is the bottom number of your blood pressure reading. People who regularly drink coffee and other caffeinated beverages, however, can develop a tolerance to it.
Patients can check how their consumption of caffeinated beverages affects their blood pressure by taking a reading within 30 minutes of consumption. Those with sensitivity will show a blood pressure increase of five to 10 points.
Performance Enhancer
Caffeine is a natural ergogenic. An ergogenic is a dietary supplement that enhances an athlete’s performance. According to Iowa State University Extension, ingesting caffeine an hour prior to exercising may increase endurance.
Breast Milk
The consumption of caffeine by nursing mothers can have an effect on their babies. The American Academy of Pediatrics says babies do not excrete caffeine easily and therefore it accumulates in their systems. Babies who drink breast milk from mothers that drink more than one cup of coffee per day may experience poor sleeping patterns, irritability and a decreased appetite.
Overdose
People can overdose on caffeine by drinking excessive amounts of caffeinated beverages and taking too many caffeine pills. According to Sidney Kaye, Ph.D. of the Institute of Legal Medicine, University of Puerto Rico School of Medicine, an excessive amount of coffee is more than five cups. The NIH states that symptoms of caffeine overdose include, but are not limited to, confusion, fever, diarrhea, hallucinations, muscle twitching and dizziness.
About this Author
Victoria Weinblatt graduated from Michigan State University with a B.S. in environmental and natural resource policy and is completing her master’s in TESOL at Shenandoah University. Weinblatt worked for five years as a nationally certified massage therapist in Seattle and Philadelphia. She earned her hatha yoga teacher certification from the Vijnana Kala Vedi Cultural Centre.
