Which of the following factors can contribute to poor sleep quality?

High caffeine consumption is a well-documented factor that can significantly contribute to poor sleep quality. Caffeine is a stimulant that can interfere with the ability to fall asleep and stay asleep, as it blocks adenosine receptors in the brain, which are responsible for promoting sleepiness. Consuming caffeine, especially in the afternoon or evening, can lead to increased wakefulness and reduce overall sleep duration and efficiency, making it harder for individuals to achieve restorative sleep.

In contrast, regular physical activity, a balanced diet, and a consistent sleep schedule are generally associated with improved sleep quality. Engaging in physical activity can promote better sleep by helping to regulate circadian rhythms, while a balanced diet provides the nutrients necessary for overall health, including sleep health. A consistent sleep schedule helps regulate the body's internal clock, making it easier to fall asleep and wake up at the desired times. Therefore, high caffeine consumption stands out as a clear factor that negatively impacts sleep quality.