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Caffeine is a widely used stimulatory compound extracted from coffee beans but can also be synthesised in a lab. Habitual caffeine use leads to tolerance, which dulls several of caffeine’s effects. It can be used to improve physical strength and endurance and is classified as a nootropic because it sensitizes neurons and provides mental stimulation. It has also been shown to be an effective ergogenic aid in short-term single and repeated bouts of maximal strength and power, intermittent team sports, and endurance exercise – because of this, it is widely used by athletes across disciplines.

How does it work?

In addition to caffeine’s stimulatory effect on the nervous system, it also blocks adenosine receptors, thus, resulting in mental alertness and other cognitive benefits. Adenosine causes sedation and relaxation when it acts upon its receptors, located in the brain. Caffeine prevents this from happening and causes alertness and wakefulness - a reduction in sedation. This inhibition of adenosine can influence the dopamine, serotonin, acetylcholine, and adrenaline systems too.

Application in sport

Caffeine is associated with a plethora of beneficial effects (Peeling et al., 2018) – hence why it’s so widely consumed in the sport, health and fitness industry in pre workouts and fat burners etc. These benefits include:

  • Increased alertness/wakefulness and suppressed sedation.

  • An increase in fat oxidation

  • An increase in aerobic exercise capacity

  • There’s a reliable and significant increase in power output in both trained and sedentary people with doses of caffeine exceeding 5mg/kg, assuming the subject isn’t caffeine tolerant. Lower doses of caffeine, aren’t as effective in producing these benefits and tolerant individuals will experience less of a benefit, if any.

  • Reduced rates of perceived exertion, lowered pain, raised endorphin release, and improved fatigue resistance.


Caffeine dosages should be tailored to each individual taking it. If you’re new to caffeine, start with a 100mg dose. Typically, 200mg of caffeine is used for fat-burning supplementation and is the general benchmark dose for standard pre-workouts. For reference, a typical Monster Energy drink is 150mg caffeine. Acute strength increases occur at higher doses, typically 500mg and above. Clinical studies tend to use a dosage range of 4-6mg/kg bodyweight.

Performance benefits have been realized during short-duration maximal dynamic resistance training exercise, where measures of muscle torque production were significantly improved after supplementation of 6 mg/kg caffeine in the 60 min prior to exercise (Duncan et al., 2014).

In summary, low to moderate doses of caffeine (∼3–6 mg/kg BM), consumed 60 min pre exercise, appear to have the most consistent positive outcomes on sports performance in research situations.


Regular caffeine use leads to tolerance. This means the effects of caffeine will be diminished, often to the point where the only benefit a user experiences is caffeine’s anti-sleep effect. This is an ‘insurmountable’ tolerance, which means more caffeine will not overcome it. Up to a month-long break from caffeine can be needed to reduce tolerance enough to experience its benefits again.

Many of caffeine’s effects like fat burning and strength benefits are subject to tolerance, and may not be noticeable or present in people used to caffeine, no matter how large the dose is.


Duncan, M.J., Thake, C.D. and Downs, P.J., 2014. Effect of caffeine ingestion on torque and muscle activity during resistance exercise in men. Muscle & nerve, 50(4), pp.523-527.

Grgic, J., Mikulic, P., Schoenfeld, B.J., Bishop, D.J. and Pedisic, Z., 2019. The influence of caffeine supplementation on resistance exercise: a review. Sports Medicine, 49(1), pp.17-30.

Maughan, R.J., Burke, L.M., Dvorak, J., Larson-Meyer, D.E., Peeling, P., Phillips, S.M., Rawson, E.S., Walsh, N.P., Garthe, I., Geyer, H. and Meeusen, R., 2018. IOC consensus statement: dietary supplements and the high-performance athlete. International journal of sport nutrition and exercise metabolism, 28(2), pp.104-125.

Peeling, P., Binnie, M.J., Goods, P.S., Sim, M. and Burke, L.M., 2018. Evidence-based supplements for the enhancement of athletic performance. International journal of sport nutrition and exercise metabolism, 28(2), pp.178-187.

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