The time change has huge consequences, both physiologically and psychologically.
The two main effects are:
- the hour change itself, which has an immediate, strong effect on most people
- the subsequent day, which gradually becomes less tiring. The hour change itself has two main effects:
- sleep schedules change. People get up an hour earlier (on average) than the day before
- people go to bed an hour earlier (on average) than the day before.
These two effects work together. If people don’t adjust their sleep schedules, then the first day is harder: people get up too early, stay up too late, and can’t fall asleep. But the adjustment works, for two reasons. First, most people are fairly good at remembering to sleep at the right time. Second, other people start to adjust, and people can adjust only so fast.
So the next day is gradually less tiring. The adjustment works even better if people go to bed earlier. People generally need around 8 hours of sleep. But most people go to bed at 9 or 10. If people go to bed at 8, the adjustment is even faster. If you don’t believe me, try it. Set your clock back one hour tonight. Tomorrow go to bed at 8 and set your clock back. You probably won’t fall asleep until very late, but the next day, you will feel much better.