Does taking melatonin before night sleep affect athletes' physical performance the next day?

The null hypothesis of no effect of melatonin on subjective sleep quality and physical performance could not be rejected (P > 0.30).

• Five milligrams of melatonin were ingested by twelve physically-active subjects before sleep in a double-blind experiment.
• Subjective sleep quality, intra-aural temperature, grip strength, and time to complete a 4 km cycling test were measured the following morning.
• The mean differences in grip strength and cycling performance between melatonin and placebo treatments were less than 1%.
• Confidence intervals for grip strength and cycling performance indicated minimal variability, ranging from -3.1 to 2.8 kg and -3.0 to 4.5 seconds, respectively.
• These findings suggest that melatonin may have little to no impact on physical performance or sleep quality in fit individuals.

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