Table 3.

Summary of studies that explored the effects of caffeine on exercise performance at altitude

Author	Participants	Protocol	Outcome
Berglund et al. 1982 [370]	Well-trained cross-country skiers (n = 14)	• 6 mg/kg caffeine • Placebo	*↑ 21 km TT 2900 m above sea level
Fulco et al. 1994 [371]	Young adult cyclists (n = 8)	• 4 mg/kg caffeine • Placebo	*↑ Time to exhaustion at 80% of their altitude-specific VO2max at 4300 m above sea level
Stadheim et al. 2015 [211]	Male sub-elite cross-country skiers (n = 13)	• 4.5 mg/kg caffeine • Placebo	*↑ Double-poling time to task failure at 2000 m above sea level
Smirmaul et al. 2017 [372]	Adult male volunteers (n = 7)	• 4.0 mg/kg caffeine • Placebo	*↑ Time to exhaustion during cycling by 12%

Outcomes are bold caffeine group specific; * = significant difference, ↑ = improved performance, TT = time trial, m = meters, mg/kg = milligram per kilogram