This question is about Running
Studies show that drinking caffeine before running may result in improved performance, speed, power, and endurance capacity [ 1
1]. Caffeine (a central nervous system stimulant that blocks adenosine) is naturally found in coffee, tea, and chocolate.
The recommended dose is 3-9 mg caffeine/kg, 30 - 90 minutes before running, which equates to 1-2 cups of brewed coffee. Runners can consume up to 400-500mg caffeine/day (about 4-5 cups of coffee) to reap the performance benefits. Drinking more than this amount may lead to negative side effects, like jitteriness or heart palpitations. Studies show that omitting caffeine or limiting intake to 50 mg/day 2-7 days before a race may maximize the benefits of caffeine on race day [ 2 3
Find out more about the best ergogenic aids for runners here
Wiles, J. D., Coleman, D., Tegerdine, M., & Swaine, I. L. (2006). The effects of caffeine ingestion on performance time, speed and power during A Laboratory-based 1 km cycling time-trial. Journal of Sports Sciences, 24(11), 1165–1171. https://doi.org/10.1080/02640410500457687
Kerksick, C. M., Wilborn, C. D., Roberts, M. D., Smith-Ryan, A., Kleiner, S. M., Jäger, R., Collins, R., Cooke, M., Davis, J. N., Galvan, E., Greenwood, M., Lowery, L. M., Wildman, R., Antonio, J., & Kreider, R. B. (2018). Issn exercise & sports nutrition review update: Research & recommendations. Journal of the International Society of Sports Nutrition, 15(1). https://doi.org/10.1186/s12970-018-0242-y
Shearer, J., & Graham, T. E. (2014). Performance effects and metabolic consequences of caffeine and caffeinated energy drink consumption on glucose disposal. Nutrition reviews, 72 Suppl 1, 121–136. https://doi.org/10.1111/nure.12124