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The Impact of Night Call: Do Doctors Need WHOOP?

By Thea Lee

The Impact of Night Call: Do Doctors Need WHOOP?

I’m at that age where friends I used to consider peers are now full-blown lawyers, doctors, and professors. PROFESSORS. What was formerly brunch conversations consisting of the shenanigans from the night before is now me talking about seeing the Beauty and the Beast movie and loving it and my friend describing the latest infant she’s brought into the world. “Yep, our Saturdays sound similar,” I respond before taking a large gulp of my drink.

In fact, I’ve had so many friends go through medical school and now residency that I pretty much know what that entails. (Just kidding, guys, I’ll never understand your pain. Never.) The tales are harrowing and one thing is abundantly clear: Residency, particularly the first year, demands a grueling schedule. The safety implications of that long shift work are of great debate in the medical community, with the Accreditation Council for Graduate Medical Education tasked with evaluating degree of risk and establishing standards accordingly.

In 2011, it was decreed that a first-year medical resident’s work shift would be capped at 16 hours. After careful review of the impact of that policy, however, that ruling is about to change. Effective July 1 of this year, first-year residents will be allowed to work 24 hour shifts without a break, with the allowance that this can extend to 28 hours when the attending physician deems it is necessary.

The task force assigned to assess the 16-hour cap reviewed over 1,000 published articles and garnered extensive input from stakeholders. Its conclusion was that the shift cap was a disruption to team-based care and supervisory systems, causing a significant negative impact on the professional education of the first-year resident. There remains, however, a great deal of disagreement as to the effect of prolonged shift work on resident medical students’ job performance and the subsequent risk this poses to the patient and the hospital.

A study published by the New England Journal of Medicine in August 2015 sought to determine the outcome of daytime medical procedures performed by surgeons who had worked the proceeding night shift. The study paired the data from 40,000 patients, looking at the outcomes of procedures conducted when the doctor had been on night-call and when they had not. The researchers found that when comparing the night-call group with the non–night-call group, there was no significant difference in the rates of death, readmission, or complications within 30 days of surgery. As such, this study would suggest that restrictions on prolonged shift work do not, in fact, affect health outcomes for patients.

Conversely, a literature review released in March 2015 with that same research question found significant evidence to suggest that sleep deprivation and prolonged shift work had adverse effects on physicians and their patients. The study documented 149 residents from 5 US academic medical centers and 6 different specialties who experienced multiple adverse effects of sleep loss on cognitive function, attention, professionalism, and task performance. Moreover, the reviewers found that:

“Subjective awareness of sleepiness seems to plateau with time, resulting in a situation in which the individual is unaware of the level of his or her impairment.”

These studies suggest a lack of conviction as to the individual impact of sleep deprivation on a medical resident and establish the difficulty of creating policies therein. At WHOOP, we know that physiology is highly individual; more often than not you can’t draw any meaningful insights from global comparisons, even when controlling for demography. As such, sleep need cannot be a generic population recommendation, but rather a daily evaluation on a personal level. WHOOP calculates daily sleep need based on four components:

  1. Baseline – this is the amount of sleep that we have learned you need based on who you are. The algorithm considers things like WHOOP-measured fitness, age, and gender.
  2. Sleep Debt – with a small decay factor, unmet sleep need from previous nights carries over, increasing the next night’s sleep need.
  3. Day StrainWHOOP Strain measures the total cardiovascular exertion experienced throughout a user’s day. We developed a mapping function between WHOOP Strain and the resulting additional sleep needed.
  4. Naps – sleep need is defined as the amount of sleep needed per 24-hour period, so nighttime sleep need is reduced by the amount of sleep already attained through naps.

Rather than establish a seemingly arbitrary cut off for the amount of time a medical resident can be on the job, medical institutions should consider the individual impact of prolonged work shifts and how this affects their recovery. It seems clear that physicians aren’t monitored closely enough to know, with a level of confidence, their physiological readiness to perform on the job. Patients, residents, and hospitals alike are better protected from risk when care schedules are informed by data.

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