Caffeine as an Ergogenic Aid for Sports Performance and Weight Loss

Caffeine is the most commonly used drug in the world with about 90% of people worldwide consuming it in regular everyday items such as tea, coffee, chocolate, energy drinks, and other foods. The effect of caffeine for reducing fatigue and increasing alertness has been recognised for centuries. In fact, it was only removed from the WADA (World Anti Doping Agency) banned substance list in 2004, and is currently on the monitored substance list. Although widely considered to provide energy enhancing benefits, caffeine provides no nutritional value, and its effects are mediated through its stimulant effect on the central nervous system (CNS) which are similar to, yet weaker than, those associated with amphetamines.

Performance Benefits

There is evidence supporting the benefits of caffeine across a range of sports, from endurance events lasting several hours like marathon or triathlon, to high intensity intermittent sports such as soccer and rugby, and sustained high intensity events from 1-60 minutes in duration like middle-distance running. 

Caffeine has been shown to produce a small but worthwhile effect on endurance performance. It has been reported to alter the functioning of receptors in the brain that regulate fatigue, influence ratings of perceived exertion (how hard the exercise feels), and lowers pain perception, all of which can improve performance. 

• In endurance events, caffeine has been shown to increase work (power) output and time to exhaustion. Caffeine mobilizes free fatty acids from the bodys adipose (fat) or intramuscular fat stores. This results in a greater use of fat for energy which slows the depletion of glycogen (carbs are broken down to glycogen in the body) and delays fatigue. As with all research on sports nutrition the improvements vary depending on the testing protocol used and benefits ranging from 0.7%-17% have been reported with improvements in the range of 4%-6% most common.
• During high-intensity exercise, the primary benefit of caffeine is evident in enhanced speed, strength and power production. Enhanced neuromuscular functioning has been reported by several researchers, resulting in greater muscular force production and decreased reaction time. 
• Caffeine also has benefits for cognitive tasks, improved short-term memory, motor learning, and an ability to sustain concentration have been reported.

How Much and When?

Research has shown that the beneficial effects of caffeine occurs when caffeine is consumed in anhydrous (tablet) form rather than in coffee or other food sources.  So how much caffeine is too much, and when should you take it?

• Caffeine has been shown to be most effective at relatively low doses with 2-3 mg/kg deemed optimal (e.g a 70kg person should consume 140-210 mg of caffeine for optimal results).There is no further dose-response benefit when consumed at higher doses.
• When taken in tablet form, caffeine reaches peak levels in the bloodstream after 20-75 minutes. It has been shown to improve performance for up to 6 hours after ingestion, and the majority of research recommends ingestion 60 minutes prior to performance for optimal absorption.

Weight Loss

As has been already noted, caffeine helps to increase endurance performance by mobilizing fatty acids which can then be burned as fuel. The best effect for fat metabolism is seen when exercising at low intensities and with relatively low doses of caffeine (2-3 mg/kg). When using caffeine to aid weight loss, it is important not to eat anything beforehand as this will cause the hormone insulin to be released and carbohydrate metabolism will begin. So the best time for fat loss will be in the morning, after an overnight fast, and with caffeine supplementation. But remember, the best way to increase fat oxidation is through regular exercise training, fat burning sessions can have a place in your training schedule but try to mix up your training by incorporating different intensities for the best response.

Adverse Effects

A common misconception is that caffeine induces dehydration during exercise.This is not supported by the literature, and several studies have failed to show any changes in sweat rate or fluid loss as a result of caffeine consumption. Several side effects are associated with caffeine consumption including gastrointestinal discomfort, increased anxiety, insomnia, heart palpitations, and tremors. It is also important to remember that caffeine is a drug and is physically addicting, discontinuation can cause some withdrawal symptoms. Typically, intakes greater than 9 mg/kg increases the risks of side effects.

Conclusion

So to conclude, caffeine has a performance enhancing effect across a broad range of sports independent of the duration. 2-3 mg/kg consumed in tablet form is optimal, taken approximately 60 minutes before you exercise.It can aid in weight loss provided it is taken under the right conditions. Finally,in order to limit your chances of side effects, keep your intake levels below 9 mg/kg.