Introduction: Supplements for Endurance and Muscle Building
Countless supplements for endurance and muscle building are now available everywhere with labels and advertisements boasting to provided athletic performance enhancement. Most are not backed by evidence-based research and are advertised through the media while promoting false benefits. The majority are not regulated by the FDA, are not clear on a standardized content of ingredients, and may not contain what the label states. The following information on supplements for endurance and muscle building is a collection of various studies showing some degree of efficacy seen in quality designed research. Some of the supplements for endurance and muscle building backed by evidence based research for improvement of athletic performance include caffeine, nitrates, creatine, and protein sources.
General Concerns of Supplements:
Caution is advised when taking supplements for endurance and muscle building to boost athletic performance. The best approach is to obtain approval from a physician prior to starting any substance. Many supplements for endurance and muscle building have been associated with severe adverse reactions. An example includes a case of a bodybuilder who appeared to be in good health with no prior tobacco use or history of major medical problems suffered from an ischemic stroke (occurs when an artery to the brain is blocked). Prior to the stoke, the bodybuilder took one supplement (dose 2 capsules) containing MaHuang extract (20 mg ephedra alkaloids), 200 mg caffeine, 100 mgL-carnitine, and 200 mcg chromium. A second supplement contained 6000mg creatine monohydrate, 1000 mg taurine,100 mg inosine, and 5 mg coenzyme Q10 per scoop. Additionally, 40–60 mg ephedra alkaloids, 400–600 mg caffeine, and 6000 mgcreatine monohydrate were taken daily for 6 weeks prior to having the stroke. (1)
Caffeine for Endurance Training:
Caffeine is a supplement used for endurance and prolonged time to exhaustion in cycling which may work by conserving potassium. Researchers examined the effects of caffeine on athletic performance, including oxygen uptake, also known as VO2 max; oxygen deficit; and certain substances that are by-products of exercise. The researchers evaluated six trained cyclists who exercised to a level beyond aerobic capacity—the ability of the body to utilize oxygen—following consumption of 5 mg per kilogram of body weight of caffeine. There was a significant increase in exercise endurance of 14.8% and the ability of the athletes to exceed aerobic capacity by 6.5%; however, no change was observed for maximum oxygen uptake. Blood potassium levels were tested as a measure of metabolic efficiency and found to be decreased after caffeine consumption and prior to exercise by 13.4%, leading the researchers to suggest the possibility that caffeine had a conserving effect on potassium, thereby prolonging time to fatigue. (2)
