The free hour: the only sleep gift the calendar gives you

At 2 a.m. this morning, clocks in most of the United States went back an hour. For one night the country received the thing the longevity industry cannot sell: an extra hour of sleep, free, no device required. Most people spent it awake. If someone handed you an hour, what would you do with it — and what does your answer say about what you think sleep is for?

What the evidence says. The American Academy of Sleep Medicine has held since 2020, and restated last year, that the United States should drop seasonal time changes in favor of permanent standard time, which aligns best with human circadian biology. Its statement cites higher risks of motor-vehicle accidents, cardiovascular events and mood disturbances after the spring change. The fall change appears gentler, and the evidence on it is thinner; what is well established is that the body's clock runs on regularity, and that shifting your schedule by an hour on weekends — social jet lag — carries some of the same costs as travel across a time zone. Last night was the one time the shift ran in your favor.

Loree’s take

The patients who come in the week after the time change are not tired because of one hour. They are tired because one hour exposed how little margin they had. If a single hour can move your week, you were already running on empty, and the cure is not a supplement. I treat this morning's extra hour as a diagnostic: if you slept through it and feel noticeably better, you have a sleep debt, and you now know what repaying it feels like.

Ben’s take

For years I programmed a watch to wake me at the moment my ring's data said my sleep cycle ended. The fall-back morning was the one morning a year the plan was wrong by an hour, I had no idea what time it was, and I felt wonderful. It took me longer than it should have to draw the conclusion.

What the stakes are. A meta-analysis of sixteen studies and 1.3 million participants associated short sleep with a 12% higher relative risk of death. A European Heart Journal analysis associated sleeping less than six hours with a 48% higher relative risk of developing or dying from coronary heart disease. Both are observational, and both point the same way as everything else in this literature. Set beside them, the most promising longevity drugs have yet to show a mortality benefit in healthy adults. Sleep is the intervention with the data, and it is the one almost nobody is prioritizing — including, on most nights, the people reading the studies.