A large-scale study of 135,000 participants shows that sleeping too little or too much is associated with an increased risk of cardiovascular death. The Multiethnic Cohort Study reveals a U-shaped risk pattern.
Shift work can disrupt circadian timing and shorten sleep, which is linked to fatigue, reduced alertness, and higher accident risk. Evidence also links night and rotating shift work to modestly higher cardiovascular risk, while cancer evidence is mixed and depends on exposure definitions.
Research on premarital cohabitation and divorce finds the risk is not from living with a future spouse, but from having multiple premarital partners.
A study published in Neuropsychopharmacology reveals how heart rate variability changes across sleep stages and how sleep apnea disrupts this balance. Evidence suggests distinct brain systems control sleep and wakefulness.
Adolescents who lack sufficient sleep experience cognitive deficits including reduced attention, impaired learning, and worse academic performance. Sleep deprivation also increases anger, irritability, and emotional regulation difficulties, and leads to dangerous behaviors like risky driving. Research shows 8-10 hours of sleep per night is optimal for adolescents.
EMDR therapy for PTSD explained in plain language: how sessions work, what studies show, WHO/NICE guidance, limits, and risks to help you choose.