Effects of Caffeine on Health & Your Physical Performance

Caffeine and Performance

Following on from the previous article – 12 Benefits of Coffee to Your Health, caffeine was mentioned as being an effective substance for dramatically improving your physical and mental performance during exercise.

This article will delve into the finer detail of how caffeine provides you with improved performance.

Caffeine is the most common psychoactive drug in the world (1) with 90% of the US population consuming it on a regular basis (2). It can increase your energy levels significantly with just a single dose, as well as increasing your performance, focus, and even helping you to burn more fat (3, 4, 5, 6).

So How Does Caffeine Improve Your Physical Performance?

When you take caffeine, it is quickly absorbed into the bloodstream, with caffeine levels peaking in your blood between 90-100 minutes. These levels remain high for approximately 3-4 hours, after which they begin to drop (7). An interesting point to note about caffeine and its effects on your body is that unlike most other supplements, it can actually affect the cells throughout your body, including your brain and muscle cells (7).

Caffeine affects your body in 7 ways:

  1. Your hormones – Adrenaline levels in your body increase when you take caffeine (8, 9) which can significantly increase your physical performance by triggering your ‘fight or flight’ response (5).
  2. Your rate of fat burning – caffeine increases your metabolism as well as specifically helping your body to burn fat through a process called ‘lipolysis’ (breakdown of fat in fat cells) (5). Studies show it can increase the rate of fat burning by up to 29% in lean body types, and 10% in obese people (10).
  3. Your body temperature – ‘Thermogenesis’ (a fancy word for heat production in your body) is increased when you take caffeine, helping you to burn more calories as a result (11).
  4. Your glycogen levels – Normally your body stores extra carbs in the form of glycogen, which your body then uses as energy during exercise. Caffeine provides your body with an alternative energy source, which allows your body to save this glycogen for later use during exercise - improving your overall endurance levels (12).
  5. Your body’s nervous system – Both your focus and energy levels can increase significantly as caffeine activates areas of your brain and nervous system (7, 13).
  6. Your endorphin levels – You can experience an increase in your general sense of wellbeing by taking caffeine. This is due to an increase in your endorphin levels (known as the ‘runner’s high’ during/after a workout) (14, 15).
  7. Your muscles – The part of your brain known as the ‘motor cortex’ (the part of the brain that signals muscle activation) is stimulated by caffeine (16).

Caffeine’s Effects on Your Strength Exercise Performance

Similar to high-intensity exercise, the results of caffeine and strength performance are mixed. One study found caffeine to have a significant benefit on bench-press performance, but no benefits on cycling sprint performance or lower body strength training (17, 18). A meta-analysis of 27 studies found that leg muscle power can be increased by up to 7% with caffeine, however it had no effect on smaller muscle groups (19).

As you can see, the above studies conflict with one another - with one finding lower leg performance to yield no benefit from caffeine, whereas the meta-analysis finds a 7% increase; so it’s hard to be conclusive here. Overall however, it seems caffeine can provide you with benefits in strength training, particularly if you are training larger muscle groups such as chest and legs.

Fat Loss and Caffeine

Studies show that caffeine does increase the amount of fat you burn during exercise through thermogenesis and the release of adrenaline, which allows your body to burn more fat and calories as a result (5, 20).

One study found that caffeine (when taken prior to exercise) can increase the release of stored fat in your body by up to 30% (5). Little wonder then that caffeine is the key ingredient in nearly all fat burning supplements, with one study finding that caffeine can dramatically increase the release of stored post-workout (19). With that being said, there is actually no evidence that caffeine can help you lose weight in the long-term when combined with exercise.

Caffeine’s Effects on Your Performance During High-Intensity Exercise

There are mixed findings when considering the effects of caffeine on high-intensity exercise.

The findings of two studies where men (with average activity levels) doing bike sprints, actually gained no benefit from caffeine when compared to water (21, 22)Compare this to the results of competitive athletes doing similar bike sprints, who displayed a significant increase in power and performance (23).

Trained vs. untrained swimmers were observed in another study. Similar to the cyclists, the untrained group enjoyed no benefit from taking caffeine. Whereas the trained athletes again displayed enhanced performance (24).

A review on the effects of caffeine on team sports seen improved sprint times in soccer players, better passing accuracy in rugby games and improved performance amongst rowing teams (25, 26, 27).

Overall, the studies suggest that the benefits you can expect from caffeine during high-intensity exercise depend on whether or not you are a trained athlete. Caffeine seems to provide little or no benefits for untrained individuals - but is highly beneficial for trained athletes.

Caffeine’s Effects on Your Endurance Performance

Caffeine is the supplement of choice for the majority of athletes due its highly effective nature. It’s so effective in fact that it has even been banned in high does by organisations such as the NCAA.

One study found that athletes who took 400 mg of caffeine were able to run approximately 2 miles (3.2 km) more than the placebo group.

Another study of cyclists revealed that caffeine was more effective than water or carbs, increasing workload by 7.4% (when compared to a 5.2% increase in the carb group) (28). When caffeine and carbs were combined in another study, performance increased by 4.6% when compared to carbs alone, and 9% compared to water alone (29).

Coffee was also researched in another study, because of its naturally high caffeine levels. It was found that coffee helped to reduce the level of effort perceived by athletes, which allowed them to work harder. Another study revealed that runners who took coffee were 4.2 seconds faster in a 1,500-meter run, when compared to those drinking de-caffeinated coffee (30, 31).

Together these studies suggest caffeine is a highly effective supplement for boosting your endurance performance.

How You Can Use Caffeine for Exercise

When using caffeine as a supplement for your exercise routine, you need to consider several things.

For example, if you drink caffeinated drinks such as coffee, soda or energy drinks regularly, then you will most likely experience reduced benefits from caffeine. This is because your body will have built up a tolerance to the supplement (32).

The most effective form of caffeine for enhanced exercise performance is known as ‘caffeine anhydrous’. However coffee is also effective and it is also full of antioxidants and provide a variety of other health benefits (33).

When determining the correct dosage for performance, body weight is a key consideration – the ideal rate being around 3-6 mg per kg (1.4-2.7 mg per Ib) of body weight. Generally this equates to about 200-400 mg for most people, although some studies even recommend dosages of up to 600-900 mg prior to training (34).

It is best to start low at around 150-200 mg to assess your tolerance, after which you can increase the dosage to around 400 (or even 600) mg. To maximise the benefits gained, you should reserve the use of caffeine for exercise/athletic events only. This is so you can maintain sensitivity to the effects - taking it 60 minutes prior to the activity/event.

How Long Does Caffeine Last in Your System?

It takes 45 minutes for 99% of caffeine to be absorbed in your body on consumption, and the effects generally last an average of about 4 to 6 hours.

Other things you should consider when deciding whether or not to become a caffeine fiend like me is the possible side effects.

These include:

  • anxiety
  • irritability
  • tremors
  • dizziness
  • elevated heart rate
  • sleep disruption or insomnia (so avoid taking it after 4 or 5 pm).

Most importantly, caffeine may not be suitable for you if you suffer from a heart condition/high blood pressure or are on certain types of medication - so be sure to consult your doctor if in doubt (7).

In Summary

So now you know that caffeine is one of the best pre-workout energy supplements available, offering a variety of benefits to boost overall performance in power sports, high intensity and endurance exercise.

For info on a supplement which promotes faster recover during and after your workouts ...

... click the link below:

==> The benefits of exercise recovery supplements


  1. AHA Journals: ‘Coffee Consumption and Coronary Heart Disease in Men and Women’
  2. PubMed: 'Food sources and intakes of caffeine in the diets of persons in the United States.'
  3. PubMed: 'Caffeine ingestion and muscle metabolism during prolonged exercise in humans.'
  4. PubMed: 'Caffeine maintains vigilance and improves run times during night operations for Special Forces.'
  5. PubMed: 'Metabolic, catecholamine, and exercise performance responses to various doses of caffeine.'
  6. PubMed: 'Caffeine maintains vigilance and marksmanship in simulated urban operations with sleep deprivation.'
  7. PubMed: 'Actions of caffeine in the brain with special reference to factors that contribute to its widespread use.'
  8. PubMed: 'Influence of caffeine and carbohydrate feedings on endurance performance.'
  9. PubMed: 'Substrate metabolism and exercise performance with caffeine and carbohydrate intake.'
  10. Wiley Online Library: 'Effects of caffeine ingestion on rating of perceived exertion during and after exercise: a meta‐analysis'
  11. PubMed: 'Caffeine: a double-blind, placebo-controlled study of its thermogenic, metabolic, and cardiovascular effects in healthy volunteers.'
  12. PubMed: 'High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is coingested with caffeine.'
  13. PubMed: 'Caffeine and the central nervous system: mechanisms of action, biochemical, metabolic and psychostimulant effects.'
  14. PubMed: 'Caffeine: implications for alertness in athletes.'
  15. PubMed: 'Effects of caffeine on muscle glycogen utilization and the neuroendocrine axis during exercise.'
  16. PubMed: 'Effects of caffeine on neuromuscular function.'
  17. PubMed: 'The acute effects of a caffeine-containing supplement on strength, muscular endurance, and anaerobic capabilities.'
  18. PubMed: 'Effect of caffeine ingestion on one-repetition maximum muscular strength.'
  19. PubMed: 'Effect of caffeine ingestion on muscular strength and endurance: a meta-analysis.'
  20. PubMed: 'Caffeine: a double-blind, placebo-controlled study of its thermogenic, metabolic, and cardiovascular effects in healthy volunteers.'
  21. PubMed: 'Caffeine, performance, and metabolism during repeated Wingate exercise tests.'
  22. PubMed: 'Effects of caffeine ingestion on performance and anaerobic metabolism during the Wingate Test.'
  23. PubMed: 'The effect of caffeine as an ergogenic aid in anaerobic exercise.'
  24. PubMed: 'Benefits of caffeine ingestion on sprint performance in trained and untrained swimmers.'
  25. PubMed: 'Caffeine supplementation and multiple sprint running performance.'
  26. PubMed: 'Enhancement of 2000-m rowing performance after caffeine ingestion.'
  27. PubMed: 'Multiple effects of caffeine on simulated high-intensity team-sport performance.'
  28. PubMed: 'Influence of caffeine and carbohydrate feedings on endurance performance.'
  29. PubMed: 'Substrate metabolism and exercise performance with caffeine and carbohydrate intake.'
  30. PubMed: 'Effect of caffeinated coffee on running speed, respiratory factors, blood lactate and perceived exertion during 1500-m treadmill running.'
  31. PubMed: 'Effect of coffee ingestion on physiological responses and ratings of perceived exertion during submaximal endurance exercise.'
  32. PubMed: 'Exercise endurance 1, 3, and 6 h after caffeine ingestion in caffeine users and nonusers.'
  33. PubMed: 'Metabolic and exercise endurance effects of coffee and caffeine ingestion.'
  34. PubMed: 'International society of sports nutrition position stand: caffeine and performance.'

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