The army’s latest overhaul of its physical training manual says adequate sleep is necessary for optimal soldier performance, according to a report from The New York Times.

The recommendation is part of an overhaul of the Army’s physical fitness training field manual, which was rebranded this week as the FM 7-22 Holistic Health and Fitness manual. No longer is the guide focused entirely on grueling physical challenges like long ruck marches and pull-ups. Now it has chapters on setting goals, visualizing success, “spiritual readiness” and, yes, the art of the nap.

“Soldiers can use short, infrequent naps to restore wakefulness and promote performance,” the new manual advises. “When routinely available sleep time is difficult to predict, soldiers might take the longest nap possible as frequently as time is available.”

It is the first update to the manual in eight years, and it reflects growing scientific evidence that peak physical performance includes more than just physical training.

Get the full story at nytimes.com.