Researchers at the University of Missouri, led by assistant professor Eunjin Tracy, published a study in the Journal of Behavioral Medicine looking at 67 older adults (average age 68), including 37 with diagnosed insomnia. Instead of just tracking sleep duration, the team looked at something called social jet lag — the mismatch between the times you wake up, eat, socialize, and go to bed on weekdays versus weekends.
What they found: people whose daily rhythm stayed consistent — same wake time, same mealtimes, same bedtime, day after day — reported less physical pain and fewer depressive symptoms than people with more erratic schedules. And this held true regardless of how much sleep people were actually getting. In other words, two people could log the same number of hours in bed, but the one with the more irregular schedule was more likely to report feeling worse.
As Tracy put it: "Our bodies function well when we regulate our circadian rhythm, but if it gets too disrupted, our bodies don't function as well." Her takeaway is that we should be thinking about sleep health across the full 24-hour cycle, not just counting hours of shut-eye.
Worth noting: this is a small, cross-sectional study of older adults, so it shows an association rather than proof of cause and effect, and it may not translate directly to younger, working adults. Still, it echoes a growing body of research on social jet lag and adds a useful nuance: consistency may matter as much as quantity.
