Sleep Deprivation or Lower Backpain

sleep as long as you want on a cold rock

• A supremely comfortable bed makes it nearly impossible to get up after only three hours — you'd be fighting the comfort every single morning
• Cold and hard surfaces naturally prompt waking once rest is complete, aligning with how humans slept for most of history
• The cold can be mitigated with blankets and padding; being forced to sleep only three hours per night cannot be mitigated at all