Poor sleep quickly raises heart disease risk, study finds

A new study from Uppsala University in Sweden has found that just three nights of restricted sleep—about four hours per night—can trigger biological changes linked to a higher risk of heart disease. Researchers monitored 16 healthy young men in a controlled lab setting as they followed two routines: three nights of normal sleep and three nights of limited sleep.

Blood tests taken before and after high-intensity exercise revealed that sleep deprivation led to elevated levels of inflammatory proteins associated with heart conditions such as coronary heart disease, heart failure, and atrial fibrillation.

The study also found that poor sleep blunted the body’s usual positive response to exercise. Notably, these changes appeared even in healthy individuals after just a few nights of poor rest.
Researchers say the timing of blood tests also influenced protein levels, underscoring how sleep impacts the body’s internal rhythms.