What does "sleep debt" refer to?

The term "sleep debt" refers to the amount of sleep one needs to make up for lost or insufficient sleep over time. When individuals do not get enough rest, they accumulate sleep debt, which can have negative effects on physical and mental health, cognition, and overall well-being. Recovery from sleep debt typically involves getting additional sleep to restore balance and ensure the body and mind function optimally.

The other choices do not accurately capture the concept of sleep debt. For instance, sleep disorders refer to various issues that disrupt normal sleep patterns rather than the accumulation of missed sleep. The time spent awake is merely the opposite of sleep and does not account for the need to recover lost rest. Finally, the financial cost associated with sleep aids is unrelated to the physiological concept of needing more sleep to compensate for what has been lost.