Experimental protocol
This was a randomized double‐blind placebo‐controlled crossover study which consisted of two 10‐day conditions separated by a washout period of at least 14 days. During both conditions, participants consumed salt pills and supplemented with either 10 mg of melatonin (HSD + MEL) or a lactose placebo (HSD + PL) capsule daily. Melatonin and placebo capsules were manufactured by SaveWay compounding pharmacy (Newark, DE) and were matched in weight and appearance. The melatonin was purchased from Letco by Fargon Medical and had the USP designation. Participants were instructed to take the capsule 30 min before going to sleep. The dose of melatonin used has been shown to decrease ROS in clinical populations with no reported side effects (Raygan et al., 