Coffee contains caffeine, a central nervous system stimulant that is known for its ability to fight fatigue and increase energy levels (1Trusted Source). This is because caffeine blocks the receptors of a neurotransmitter called adenosine, and this increases levels of other neurotransmitters in your brain that regulate your energy levels, including dopamine (2Trusted Source, 3Trusted Source). One small study found that consuming caffeine increased time to exhaustion during a cycling exercise by 12% and significantly reduced subjective levels of fatigue in participants (4Trusted Source). Another study had similar findings, reporting that consuming caffeine before and during a round of golf improved performance, increased subjective energy levels, and reduced feelings of fatigue (5Trusted SourceTrusted Source).