Caffeine, considered a Nootropic, comes naturally from coffee beans and tea leaves and can also be made synthetically in a lab. Nootropics are compounds that enhance cognitive potential and a person’s overall state of well-being (including other supplements such as fish oil, creatine, vitamin b12, etc.). Caffeine works by antagonizing adenosine receptors in the brain that cause sedation. By inhibiting this action, alertness and wakefulness is experienced, and dopamine, serotonin, and adrenaline are all influenced. These characteristics are what make caffeine a strong stimulant.
Caffeine is used to improve physical strength and endurance through mental stimulation (reference 9). In fact, studies have shown that there appears to be a reliable and significant increase in power output for both weight lifting and cycling in trained and sedentary people (references 5, 6, 7, 8). It is also used as a fat burner and appears to provide a notable benefit to anaerobic cardiovascular exercise (references 1, 2, 3, 4). Ongoing use of caffeine has been associated with a reduced risk of Alzheimer’s, cirrhosis, and liver cancer. However, tolerance starts to build with habitual use until the only benefit is the sleep-inhibiting characteristic. Tolerance to caffeine can be reduced by ceasing use for a month. Caffeine has also been proven to reduce headaches, improve asthma, and reduce the risk of diabetes.
Caution should be exercised if individuals are either not used to caffeine ingestion or currently have high blood pressure (reference 11, 12). Furthermore, due to its stimulatory nature, the use of caffeine close to periods of sleep may hinder the quality and effectiveness of sleep. In addition to insomnia, caffeine may cause nervousness and restlessness, stomach irritation, nausea and vomiting, increased heart rate and respiration, and other side effects.
Caffeine should not be mixed with stimulatory drugs, especially ephedrine (reference 10). Overstimulation can lead to serious side effects and heart problems.
Caffeine dosages vary based on an individuals tolerance. A 100mg dose is typically the starting point for people unfamiliar with stimulants. 200mg of caffeine is commonly used for fat-burning supplementation, while acute strength increases occur at higher doses of 500mg and above. The National Collegiate Athletic Association (NCAA) has limitations on the amount of caffeine athletes can consume. Amounts of caffeine greater than 15 mcg/mL of urine are prohibited. That amount is equivalent to approximately 8 cups of coffee (each cup containing 100 mg of caffeine), or 800 mg.
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