I could not put down the book The Power of When: Discover Your Chronotype–and the Best Time to Eat Lunch, Ask for a Raise, Have Sex, Write a Novel, Take Your Meds, and More by Dr. Michael Breus. In it, he describes the best time of day to do over fifty daily activities based on your particular circadian rhythm—that is, your chronotype. The four chronotypes (Bear, Lion, Wold and Dolphin) differ greatly in the best time to do most activities of daily life. However, one activity all chronotypes should not do at any time is sleep in! Evidence points to the fact that “If you stay in bed on the weekend for two hours longer than usual, you’re far more likely to be grouchy, fat, and sick” (Breus 182). The best time to wake up on weekends is within one hour of your usual wake up time during the week.
Sunday Night Insomnia and Sleep Debt
Dr. Breus highlights an annoying occurrence that happens to a lot of us the first night of the week—”Sunday Night Insomnia“. You know that feeling when you lay down at a decent hour on Sunday night but absolutely cannot fall asleep? Staring at the ceiling all night sure makes me frustrated come Monday morning. Sunday Night Insomnia starts on Friday and Saturday. We’ve all been out having a good time with friends, then look at the clock and see it’s past midnight. “That’s okay,” we think, “I’ll can just catch up on sleep tomorrow, right?”—wrong.
“Catching up on sleep” by sleeping much later into the morning is ineffective. By sleeping far past your normal wake time, you are not gaining more deep/restorative (Stage 3 and Stage 4) sleep because this kind of sleep happens early on in the sleep cycle. By sleeping later into the morning, you are only getting more light sleep (REM) that does little to improve physical restoration. You end up just falling into sleep debt for the rest of the week. “The debt you rack up in a few days of not sleeping well and waking up exhausted can’t be balanced by just sleeping in on the weekends” (Breus 182).
Sometimes staying up past your bedtime in order to spend quality time with others is totally worth it. Just know that even if you stay out late one night, you should make the sacrifice of waking up at or around the same time you normally do the next morning to avoid the negative health associations of having an inconsistent wake time that I’ll discuss below.
Studies on Sleep Consistency and Health Outcomes
In their systematic review on sleep behaviors, Chaput and colleagues (2020) conclude, “… greater variability in sleep … [is] associated with adverse health outcomes in adults“. Three studies within this review investigated the influence of “weekend catch-up” sleep on health outcomes. Interestingly, all three of the studies showed that weekend catch-up sleep was associated with positive health outcomes such as a lower BMI (Im et al. 2017) and lower cardiometabolic risk (Hwangbo et al. 2013). Well, this sounds like it goes against everything I previously wrote.
HOWEVER: within these studies, it was found that sleeping in by only an extra ONE HOUR, not more, is associated with positive health outcomes. That is why I say that the best time to wake up on weekends is within one hour of your usual wake up time during the week. The better option would be to consistently get enough sleep all week long, but we are not perfect. “Catching up on sleep” by just an hour on weekends is way better than doing nothing at all.
The evidence shows that sleeping in more than one hour past your usual wake-up time may be harmful. People who sleep in on weekends generally fare worse than people who maintain a relatively consistent sleep schedule:
- In a large study, it was found that people who slept two hours extra on the weekends had greater BMIs and biomarkers for diabetes and inflammation than people who maintained a regular sleep schedule (Parsons et al., 2015, from Breus 181).
- Another group of researchers found, similarly, that a higher difference in sleep time between the workweek and weekend is associated with inflammation (Girtman et al. 2022).
- Slavish and colleagues (2019) report that people who have greater differences in night-to-night sleep time have “increased odds of having neurological, breathing, and gastrointestinal problems, as well as pain and depression”.
So, all in all, it truly does look like sleeping in (for more than one hour) on weekends might make you grouchy, fat and sick. Keep it safe and go to bed and wake up on time because the best time to wake up on weekends is within one hour of your usual wake up time during the week.