Which substance does Tina limit after a certain time to improve her sleep?

Limiting caffeine is significant for improving sleep because caffeine is a stimulant that can increase alertness and make it difficult to fall asleep. Consuming caffeine, especially in the hours leading up to bedtime, can interfere with the body's natural sleep-wake cycle. It stimulates the central nervous system, often prolonging the time it takes to fall asleep and leading to poorer quality sleep throughout the night.

By restricting caffeine intake as bedtime approaches, individuals like Tina can help ensure that their body is in a more relaxed state conducive to sleep, allowing them to both fall asleep faster and enjoy deeper, more restorative rest. This practice is particularly important for those who may already experience difficulties with sleep, as eliminating or reducing caffeine can significantly enhance overall sleep quality.