Caffeine is a naturally occurring stimulant that belongs to a class of compounds known as xanthines. It can be found in a number of natural products, but also produced synthetically.

Caffeine works by blocking the action of a neurotransmitter called adenosine, which is responsible for promoting sleep and suppressing arousal. By blocking the action of adenosine, caffeine can increase alertness, reduce fatigue, and improve cognitive performance.

Caffeine is classified as a psychoactive drug because it affects the central nervous system, and it has both positive and negative effects on the body depending on the dose and individual tolerance. At low to moderate doses, caffeine can have beneficial effects such as improved cognitive function, increased endurance, and enhanced mood. However, at high doses, caffeine can cause negative side effects such as anxiety and insomnia.

Caffeine is widely consumed and has a number of performance benefits.

1. Spare muscle glycogen. Caffeine helps the body utilise fat as a fuel source instead of relying on glycogen stores. Caffeine increases fat oxidation and decreases muscle glycogen breakdown by increasing the breakdown of fatty acids, which are then used as a fuel source during exercise. This leads to reduced reliance on glycogen stores, sparing them for later use. In addition, caffeine Improves insulin sensitivity which can help the body use glucose more efficiently and spare muscle glycogen. Overall, through sparing muscle glycogen, caffeine can be particularly beneficial for endurance athletes who need to maintain their glycogen stores over long periods of exercise.

2. Increase muscle activation. Caffeine has been shown to increase muscle activation during exercise, particularly in high-intensity and strength training activities. This effect occurs as an effect of caffeine whereby it…

• Increases central nervous system stimulation resulting in an increase in muscle activation and improved performance.
• Decreases perceived exertion allowing individuals to push harder and activate their muscles to a greater degree.
• Enhances motor unit recruitment leading to more muscle fibers being activated during exercise.
• Improves muscle contractility causing muscles to contract more efficiently and with greater force.

3. Increase alertness and improve decision making. Caffeine has a number of beneficial cognitive functions which may have a positive impact on performance.

• Blocks adenosine receptors: Adenosine is a chemical in the brain that is associated with sleep and relaxation. Caffeine blocks adenosine receptors, which can increase alertness and reduce feelings of fatigue.
• Increases dopamine levels: Dopamine is a neurotransmitter that is associated with feelings of pleasure and reward, and it can improve motivation and decision making.
• Improves cognitive function; including attention, reaction time, and memory.
• Enhances mood: Increasing levels of neurotransmitters such as dopamine, serotonin, and norepinephrine can help individuals feel more positive and motivated.

4. Improve endurance. The impact of caffeine on endurance is significant and has been identified through the following mechanisms…

• Increases fat oxidation
• Reduces perceived exertion
• Enhances muscle activation
• Improves respiratory function
• Increases pain threshold

5. Reduce the rating of perceived exertion (RPE). This means that individuals feel like they are exerting less effort even when they are performing at the same intensity. Rate of perceived exertion is a subjective measure of how hard someone feels like they are working during exercise or physical activity. RPE is typically measured on a scale of 0 to 10, with 0 indicating no effort at all and 10 indicating maximum effort. Caffeine reduces RPE as it blocks adenosine receptors, enhances pain tolerance and enhances motor unit recruitment. The overall effect is an athlete may be able to push harder for a longer period of time within training and competition.

Overall, there are a huge number of benefits from the consumption of caffeine in order to enhance performance. However, it's worth noting that the effects of caffeine can vary depending on the individual and the amount consumed. Excessive consumption of caffeine can also have negative effects, such as insomnia, and increased heart rate. It's important to consume caffeine in moderation and to be aware of your individual tolerance levels. The recommended dose varies by body weight, but it’s typically about 200–400 mg, taken 30–60 minutes before a workout.