Our bodies run on predictable daily schedules. As morning approaches, our body temperature begins to rise, and our cortisol levels climb. Our heart rate and blood pressure spike upon awakening. By mid-morning, we tend to be at our most alert, while many components of athletic performance—including strength, coordination, and flexibility—peak in the afternoon. As darkness descends, the pineal gland dials up its release of melatonin; while we sleep, gastric-acid secretion surges. Similar 24-hour cycles, or circadian rhythms, govern nearly every cell, tissue, and organ in the human body, and almost all of its physiological functions.
Hospitals, it turns out, have daily rhythms too, and they don’t always sync with our own. According to a recent Proceedings of the National Academy of Sciences study, conducted before hospitals were handling surges in coronavirus cases, hospital clinicians prescribe medications in predictable patterns, dispensing the majority in the morning. This schedule—what the researchers call a “systemic bias in the timing of medicine”—may be convenient for clinicians, but it’s not necessarily best for patients or consistent with their biological clock.
Hospitals run all day and night, and in theory medications could be doled out whenever they’re needed. “Our findings challenge this notion,” the study’s authors write, “and reveal a potential operational barrier to best clinical care.” For busy doctors, time is a scarce resource—and hospitals are generally designed to deliver care as quickly and efficiently as possible. But the human body keeps its own time, so optimal care may be less of a race than a chronologically choreographed dance.