Don’t sleep on this warning.

A sleep scientist has revealed the most commonly overlooked symptom of the dangerous sleep disorder that affects millions of Americans — urging them to pay closer attention to the quality of their nightly shuteye.

“Obstructive sleep apnea (OSA) is an extremely common condition, impacting hundreds of millions of people worldwide. Yet, millions suffer in silence because common symptoms of OSA may be overlooked or difficult to detect because they occur during sleep,” sleep scientist Dr. Joachim Behar told The Post.

OSA occurs when the throat muscles relax and block the airway repeatedly during sleep.

The doctor explained that “when a patient ignores the problem or is misdiagnosed, OSA becomes a risk factor for very serious conditions, including Type 2 diabetes and heart disease” — the leading cause of death for men, women, and people of most racial and ethnic groups in the United States.

Keep reading at nypost.com.

Dr. Joachim Behar is a professor in the Technion Faculty of Biomedical Engineering.