Sleep deprivation is a silent killer, especially in the military. Now, the service is scrambling to address the vicious cycle of exhaustion and overwork within the 7th Fleet that officials see as the root cause of the USS Fitzgerald and the USS McCain collisions that claimed the lives of 17 sailors over the summer.

The Navy will start with changing its sleep schedules, according to Naval Surface Force-Pacific commander Vice Adm. Tom Rowden’s on Sept. 19, giving overworked sailors a chance to actually get some rest between long watches.

“We will institute circadian rhythm” — which typically means an acknowledgment of the body’s 24-hour cycle — “in our watchbills and shipboard routines,” said Rowden, who is retiring early for reasons unknown. “Many units are already utilizing circadian rhythm, and I realize the pace of operations might dictate some modifications to the manner in which circadian rhythm is implemented.”

For Rowden, the needs of the sailors have too long been overlooked, and his remarks came a day after lawmakers, led by Sen. John McCain, grilled Navy officials regarding the routine burdens of the 100-hour work-week frequently faced by sailors.

“As stated in previous warfighting serials, personal readiness is equally important as material readiness,” Rowden said. “Additional guidance and implementation tools will be forthcoming.”

According to memos uncovered by Navy Times, skippers have been granted a number of options for watch schedules, which will better adhere to the sailors' natural rhythms.

The Navy’s exhaustion is no secret. The RAND Corporation performed a two-year sleep study of the services in 2015, and found “a high prevalence of insufficient sleep duration, poor sleep quality, daytime sleepiness, fatigue, and nightmares,” Task & Purpose previously reported in August. And the Navy was among the hardest hit: In particular sailors with multiple prior deployments “had greater sleep-related daytime impairment” than those without.

For Navy officials, this is an obvious problem for a 7th Fleet tasked with keeping a bellicose North Korea at bay. “Fatigue has measurable negative effects on readiness, effectiveness and safety,” Rowden said of the Navy’s sleep schedules in 2016. “After a day without sleep, human performance drops to dangerously ineffective levels.”

The Navy isn’t just taking a long, hard look at lack of sleep. On Sept. 18, two senior officers — Rear Adm. Charles Williams and Capt. Jeffrey Bennett —in the 7th Fleet were also removed for “a loss of confidence in their ability to command,” CNBC reported. These departures follow a perceived lack of leadership in Williams, chief of the Navy's largest battle force, and doubts that Bennett could continue commanding the destroyer squadrons under the 7th Fleet.

Training remains a major issue. By June, a third of warfare training certifications for the Navy's destroyers and cruisers in Japan had expired, CNN reported after obtaining numbers from a Government Accountability office study on the Pacific Fleet was released. And Rowden said the Navy is taking all these issues into account.

“We must take every opportunity to evaluate how we are executing our core competencies, and improve at every turn,” he said. “As a community, we will always make the course corrections necessary to safely conduct operations at sea.”

(Update: This post has been correct the fact that Vice Adm. Rowden’s comments came from an All Naval Surface Forces Memo dated Sep. 19, not a Sep. 20 farewell address. It has also been updated to reflect that Rowden’s request for early retirement would release him from the service several months before his planned separation date, not a year early, as was previously stated.)