These findings, along with other studies that reached similar conclusions, prodded the ACGME to establish new duty-hour rules. These regulations were adopted nearly seventy years after Congress directed the Interstate Commerce Commission to establish hours of service rules for another group of shift workers, namely truckers. It seems that a fully loaded eighteen-wheeled truck looming in your rearview mirror strikes more terror and trepidation than watching a bespectacled, studious, yet exhausted intern making life-and-death decisions in the 26th hour of their work shift.
Playing with the rules of nature that disrupt the natural sleep–wake cycle and other circadian rhythms can be hazardous to everyone’s health.
What Jet Lag Can Teach Rheumatologists
Circadian rhythms are a universal phenomenon found across all plant and animal species. In the early 1700s, the French astronomer Jean-Jacques d’Ortous de Mairan demonstrated that the leaves of Mimosa pudica continue to open and close every 24 hours, even when the plant was enclosed in a sealed box. The invention of artificial light, followed by the creation of night-shift work and the advent of jet travel have all disrupted the natural pattern of alignment between the external light–dark cycle and our internal clock, which was set to a 24-hour day early in evolution.3 The circadian clock, identified in the 1970s as being situated in the suprachiasmatic nuclei (SCN) of the hypothalamus, promotes alertness during the day and sleep at night.
Now that most readers are presumably beyond the stage of training requiring lengthy shift work, the most likely situation to cause sleep deprivation (other than raising kids!) would be jet travel. Jet lag is a recognized sleep disorder that results from crossing time zones too rapidly for the circadian clock to keep pace, resulting in a temporary misalignment between the clock and local time. The clock is slow to reset, so after several time zones have been traversed, the endogenous signals for sleep and wakefulness fail to match the local light–dark and social schedules.
Sleep is not a luxury, rather it is a critical component of the circadian cycle. Though inadequate sleep can be harmful, especially when driving or operating heavy equipment, the total lack of sleep can be fatal, as evidenced by the rare syndrome of familial fatal insomnia, a prion disease caused by a mutation at codon 178 of the prion protein gene.4 Affected individuals develop a rapidly progressive and ultimately fatal disease characterized by untreatable insomnia, dysautonomia, and pathologic motor signs.
