HealthJune 17, 2026

Your Reaction Time on a Bad Watch Might Match Someone Legally Drunk

Fatigue is shipping's quietest safety risk. Here's how to protect sleep on a rotating watch.

Fatigue is the safety risk everyone knows about and almost nobody manages well. Six-on-six-off watch systems, port calls at 3am, and cabin heat that never quite cools all chip away at the one resource that fixes almost everything else — and most crews only notice once it's already gone.

Sleep debt compounds. Missing 90 minutes a night for a week doesn't feel like much until your reaction time on the bridge matches someone legally drunk — a comparison fatigue researchers have made directly. The fix isn't heroics. It's discipline: a consistent pre-sleep routine even on a rotating schedule, blackout curtains or an eye mask, and treating your off-watch sleep window as a non-negotiable appointment, not a flexible suggestion.

Caffeine has a longer half-life than most people think — a coffee at the end of a watch can still be blocking sleep six hours later. Shifting your last caffeine intake earlier is one of the highest-leverage changes available.

Rest isn't the reward for finishing the watch. It's the preparation for the next one. Protect it like you'd protect any other piece of safety equipment.