Strong evidence

Caffeine improves several aspects of exercise performance.

In practice

Coffee before training is a legitimate performance aid, not a placebo. Its downside is what it does to sleep — and sleep is doing more for your training than the caffeine is.

What it doesn't say

Individual response varies a lot, and tolerance builds. Anyone with a heart condition, high blood pressure, or who is pregnant should take medical advice on intake.

Source

• Grgic J, Grgic I, Pickering C, Schoenfeld BJ, Bishop DJ, Pedisic Z (2020). Wake up and smell the coffee: caffeine supplementation and exercise performance — an umbrella review of 21 published meta-analyses. British Journal of Sports Medicine, 54(11):681–688. doi.org/10.1136/bjsports-2018-100278