Your Heart Health Declines After Only Three Nights of Poor Sleep

We’ve long understood that insufficient sleep negatively affects heart health, but scientists are now beginning to uncover the specific mechanisms behind this damage.

Three Nights of Poor Sleep Affect Heart-Related Blood Markers

In a recent study, Uppsala University researchers in Sweden found that limiting sleep to about four hours per night for just three nights changes blood composition and increases the risk of heart disease.

The study examined inflammatory proteins in the blood, which the body produces during periods of stress or illness. When these protein levels remain elevated over time, they can harm blood vessels and increase the likelihood of conditions such as heart failure, coronary artery disease, and atrial fibrillation (an irregular heartbeat).

To carry out the study, researchers monitored 16 healthy young men over several days in a controlled laboratory environment, carefully regulating their diet, physical activity, and exposure to light.

The participants underwent two different sleep routines: three nights of normal sleep (8.5 hours per night) and three nights of restricted sleep (4.25 hours per night). Following each sleep period, they performed a brief, high-intensity cycling session, with blood samples taken both before and after the workout.

Researchers analyzed nearly 90 different proteins in the blood. They observed a noticeable increase in inflammatory markers associated with heart disease after the sleep-deprived nights.

Normally, exercise boosts beneficial proteins like interleukin-6 and BDNF, which support both brain and heart health. However, these positive effects were noticeably diminished following the nights of poor sleep.

Including Young Adults

Remarkably, these changes were observed even in young, healthy adults after just a few nights of insufficient sleep. This is concerning, especially considering how frequently adults experience disrupted sleep—and that about one in four people work shifts that interfere with their natural sleep cycles.

The researchers also found that the timing of blood collection made a difference: protein levels shifted between morning and evening, with even greater variation after sleep restriction. This indicates that sleep influences not just what circulates in our blood, but also when those changes are most pronounced.

While modern life often pushes us to sacrifice sleep for work, social activities, or screen time, studies like this highlight an important truth: the body keeps track—quietly, biochemically, and without leniency.

Read the original article on: Sciencealert

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