Sleep less to get more done? The sleep debt trap

When your schedule is overflowing, sleep is often the first thing to go. One less hour at night to finish a project, watch another episode, or just unwind. You tell yourself you'll get used to it. A famous study shows that this is exactly where the trap lies.

The 14-night experiment

In 2003, Hans Van Dongen, David Dinges and their colleagues at the University of Pennsylvania published a very rigorous experiment in the journal Sleep. 48 healthy adults, aged 21 to 38, spent two weeks in the lab. For 14 days, some slept 8 hours a night, others 6 hours, and others 4 hours. A final group was kept completely awake for 3 days.

Every day, the researchers measured attention, working memory and speed of thinking, and asked participants how sleepy they felt.

What they found

The results are striking:

• Sleeping 6 or 4 hours a night led to a drop in performance that built up day after day, on every task.
• After two weeks at 6 hours a night, participants had reached a level of impairment in attention and working memory comparable to what was seen after a full night without sleep. At 4 hours a night, it was the equivalent of two sleepless nights.
• The most unsettling part: their feeling of sleepiness rose mostly during the first few days and then leveled off. The authors conclude that participants were largely unaware of how much their abilities had declined.

That last point is the one that matters for you. “I've gotten used to sleeping less” is often a feeling, not a measured reality. You feel more or less the same, but you're working less well.

So how many hours?

In 2015, the U.S. National Sleep Foundation brought together a panel of 18 experts from several disciplines to review the scientific literature on sleep duration. Their recommendation for young adults and adults: 7 to 9 hours a night. For older adults, 7 to 8 hours.

These numbers are benchmarks for healthy people without a sleep disorder. Needs vary from person to person, but if you regularly sleep 6 hours and tell yourself it's enough, Van Dongen's study is an invitation to ask yourself the question honestly.

Protecting your sleep when you're swamped

The goal isn't to aim for the perfect night, but to stop treating sleep as the thing you cut when you need more time. A few concrete steps:

1. Set a bedtime, not just a wake-up time. We always set an alarm, but rarely the time to go to bed. Count back from your wake-up time to aim for at least 7 hours.
2. Set a reminder 30 to 45 minutes before. That's your signal to close the laptop, prepare for the next day and slow down.
3. Empty your head onto paper. If tasks are running through your mind at bedtime, write them down. They'll be there tomorrow, so you no longer need to hold them in memory.
4. Keep similar hours on weekends. A regular rhythm helps your body know when it's time to sleep.
5. Observe yourself for two weeks. Each morning, note what time you went to bed and how you feel. You'll quickly see the point at which your days start getting harder.

Sleep as an investment in your day

When you're short on time, it's tempting to take an hour from the night. But the 14-night experiment suggests that an hour gained in the evening can cost you attention and memory the next day, without you even noticing. Thinking of sleep as part of how you organize your life, and not as whatever's left once everything is done, is one of the most worthwhile changes you can make.

And if, despite good habits, you're still exhausted or sleeping very badly for weeks, talk to a doctor: some sleep disorders can be treated.

With ForgeMe

You can create an evening ritual in ForgeMe, for example “screens off and tomorrow's list,” with a reminder at the time you want to start winding down. Tasks running through your head can go straight into tomorrow's list, and the ritual's streak helps you keep it up several nights in a row.