Caffeine is well known as a mental stimulant, but caffeine also has major benefits in physical performance. Consuming caffeine before exercise burns more calories, increases alertness, reduces the perception of fatigue, and actually has the ability to increase acute strength.
Effect
Magnitude of Effect
Level of Evidence
Consistency of Research
Conclusion
Studies
Anearobic Running Capacity
High ↑↑
10/10
Medium
In a double blind trial, caffeine group had greater peak power achieved during sprints (7% in the first half, 6.6% in the second half) and did a greater total volume of work (8.5% in the first half, 7.6% in the second).
Power Output
High ↑↑
10/10
Very High
Across multiple studies, there is a reliable and significant increase in power output (both weight lifting as well as cycle ergometer measurements) in both trained and sedentary persons with medium or high levels of caffeine.
Wakefulness
High ↑↑
8/10
Very High
Caffeine is reliable and effective in increasing the state of wakefulness and suppressing sedation
Training Volume
Medium ↑
8/10
Medium
Proven increase in training volume (overall work performed during a workout) associated with caffeine ingestion relative to placebo, extending to both weightlifting and anaerobic cardiovascular exercise
Fat Oxidation
Medium ↑
10/10
Very High
An increase in fat oxidation is apparent (assessed via increased serum glycerol and free fatty acids) which is thought to be secondary to increases in adrenaline