Sleep deprivation is on the rise among contemporary youths, thanks to a combination of poor sleep hygiene (having one's sleep disrupted by noise, light, and electronic devices), caffeine intake, beds that are too warm, a mismatch between biologically preferred sleep schedules at around puberty and social demands, insomnia, growing homework load, having too many extracurricular activities. Consequences of sleep deprivation include low mood, worse emotional regulation, anxiety, depression, increased likelihood of self-harm, suicidal ideation, and impaired cognitive functioning. In addition, teenagers and young adults who prefer to stay up late tend to have high levels of anxiety, impulsivity, alcohol intake, and tobacco smoking.