The answer to this question is complicated because sleep debt is very real. However, “debt” implies you can pay it back, which is where it gets complicated. According to the Centers for Disease Control and Prevention (CDC), when you’re not getting enough sleep, sleep debt is the amount of time you’re behind.
The idea behind sleep debt is that you can sleep to “pay down” the debt. However, a 2019 article published by Current Biology discusses how researchers found that sleep debt cannot be easily repaid. In their research, participants who would sleep in on the weekends to make up for the sleep lost during the week still ended up with detrimental effects on their bodies. Namely in the way the body uses insulin, weight issues resulting from increased nightly calories, and reduced energy.