Caffeine, a psychomotor stimulant found in many beverages, is present in many pre-workout stimulants. Used on its own, caffeine acts to increase the activity of your central nervous system, and this increase may lead to an increase in performance. Caffeine also possesses slightly addictive properties, and some people experience withdrawal symptoms after stopping prolonged use. Consult a health care professional before using any pre-workout supplement.
Caffeine, most commonly consumed as a product of the coffee plant, can be found in many other types of plants. Caffeine is commonly available in soft drinks, teas and energy drinks. Some products may not list caffeine as an ingredient but list other plants that produce caffeine, such as guarana, which is just as high in caffeine as coffee. Caffeine also is commonly found in pre-workout stimulants, largely for the stimulant effect. Caffeine also can be seen in fat-burning supplements.
Speed and Power
Caffeine's stimulant effects result in it being an effective pre-workout supplement. Short-term endurance and performance can increase following caffeine supplementation. In a study published in the "The Journal of Sports Medicine and Physical Fitness" in December 2010, caffeine supplementation prior to sprinting improved sprint time in all study participants. In a January 2011 study in the "Journal of Strength and Conditioning Research," caffeine supplementation pre-workout improved muscular endurance and the ability to complete repetitions on the bench press.
Caffeine taken before a workout can improve long-term endurance. A review of 21 studies was published in the February 2011 issue of the "International Journal of Sport Nutrition and Exercise Metabolism." Upon review of the studies, researchers concluded that, in all endurance studies, supplementing with caffeine showed a marked improvement. However, not all of the effects of caffeine are positive.
Long-term continued use of caffeine can lead to addiction, and termination of use can present withdrawal symptoms. Because habitual caffeine users quickly develop a tolerance, if you continue to use caffeine as a stimulant, the effectiveness lessens over time. This can lead to dependency and long-term addiction known as caffeinism, which can present as moodiness, anxiety, insomnia and twitching. Withdrawal symptoms include headache, nausea, irritability, drowsiness and possibly joint pain. Symptoms of withdrawal normally peak at 48 hours and taper off.