Short Early-Afternoon Naps Improve Alertness and Performance

Overview

• News coverage on Wednesday and Thursday reiterated a 1995 NASA pilots study that found a roughly 26-minute nap raised alertness by up to 54 percent and task performance by about 34 percent.
• Sleep specialists recommend brief naps of 20 to 30 minutes taken in the early afternoon, roughly between 1 p.m. and 3 p.m., as the best way to boost concentration without disrupting night sleep.
• Longer naps increase the chance of sleep inertia, a state of grogginess and slowed thinking that occurs when someone wakes from deeper sleep stages and that can reduce immediate performance.
• Experts warn that naps are a short-term restorative tool and not a substitute for nightly sleep, and that chronic short sleep of around four hours per night causes cognitive impairment comparable to heavy alcohol use and raises long-term health risks.
• Evidence remains inconclusive on whether daytime napping lowers long-term cardiovascular risk, but wider acceptance of short naps could ease daytime fatigue and reduce mistakes at work if paired with policies that protect regular nighttime sleep.