This seems to contradict recent study that I came across [1]:
The mortality rate among participants with short sleep during weekdays, but long sleep during weekends, did not differ from the rate of the reference group. Among individuals ≥65 years old, no association between weekend sleep or weekday/weekend sleep durations and mortality was observed. In conclusion, short, but not long, weekend sleep was associated with an increased mortality in subjects <65 years. In the same age group, short sleep (or long sleep) on both weekdays and weekend showed increased mortality. Possibly, long week- end sleep may compensate for short weekday sleep.
It may be important to distinguish between (A) long-term mortality versus (B) impaired cognition and mood on a daily basis.
To use an analogy, you might be able to maintain a car so that its lifetime mileage isn't reduced, but that doesn't mean that it can't suffer in terms of handling, speed, comfort, etc.
I'm someone who often gets insufficient sleep during the week and, anecdotally, sleeping 12 - 16 hours on Friday and Saturday night seems to rejuvenate me. I've always felt like I could pay off sleep debt if I really get a lot of sleep on the weekends in proportion to how much I lost during the week.
The mortality rate among participants with short sleep during weekdays, but long sleep during weekends, did not differ from the rate of the reference group. Among individuals ≥65 years old, no association between weekend sleep or weekday/weekend sleep durations and mortality was observed. In conclusion, short, but not long, weekend sleep was associated with an increased mortality in subjects <65 years. In the same age group, short sleep (or long sleep) on both weekdays and weekend showed increased mortality. Possibly, long week- end sleep may compensate for short weekday sleep.
[1] https://onlinelibrary.wiley.com/doi/pdf/10.1111/jsr.12712