Nearly one in four U.S. high school students now sleeps five hours or less on school nights. That is not a marginal shift. That is a collapse.
A study published in JAMA, drawing on self-reported data from more than 120,000 students between 2007 and 2023, tracked the decline. The share of teens getting less than seven hours of sleep rose from roughly 69 percent to 77 percent. The share getting less than five hours — severe deprivation — jumped from about 16 percent to 23 percent. That is a 7-point climb in the worst category.
Seven hours is itself below the eight-hour threshold that was once considered normal. That threshold is now increasingly rare.
The study’s authors argue the numbers justify policy change. They point to later school start times as a concrete step. The logic is straightforward: if school starts later, teens can sleep later. Their natural circadian rhythms shift during adolescence. Early start times fight that biology. Later start times work with it.
This is not a niche problem. The trend was seen across demographic groups. It was not confined to vulnerable populations, though teenagers already experiencing depression were hit especially hard. Chronic sleep loss in adolescence is linked to higher risks of depression, anxiety, cardiovascular disease and diabetes. It also damages academic performance and concentration.
Consider what 23 percent means. Nearly a quarter of the high school population is running on five hours or less. That is a level of deprivation associated with impaired judgment, weakened immune function and emotional instability. It is the kind of sleep debt that accumulates. One bad night is recoverable. Chronic short sleep is not.
The data is self-reported, which carries known limitations. Teens may misremember or misreport how long they actually sleep. But the direction is clear. A 7-point rise in the most severe category over 16 years is not a measurement artifact. It is a trend line pointing straight down.
What is driving it? The study does not name causes. But the timing aligns with the spread of smartphones, social media and round-the-clock connectivity. Homework loads have not shrunk. Extracurricular demands have not eased. The pressure to perform academically has, if anything, intensified. Something had to give. What gave was sleep.
The consequences are not abstract. A sleep-deprived teenager is not merely tired. They are more susceptible to mental health crises. Their bodies are under chronic stress. Their brains, still developing, are denied the restorative processes that only sleep provides. The JAMA paper adds to a body of evidence that adolescent sleep is a public-health issue. It is not a lifestyle choice. It is a structural problem.
Later school start times are not a cure-all. They are a lever. Several school districts have already moved in that direction, with mixed results. Some saw improved attendance and alertness. Others struggled with bus schedules and after-school activities. The research suggests the benefits outweigh the logistical headaches. But implementation matters.
The study’s authors argue the findings are serious enough to justify action. Families with concerns should consult a doctor. That is individual advice for a collective problem. One family can adjust a bedtime. They cannot change a school start time. They cannot change a culture that prizes productivity over rest.
The number that sticks is 23. Nearly one in four. That is not a fringe group. That is a generation running on empty.
