How Working Too Much Can Actually Kill You

A 31-year-old woman in Japan who put in more than 150 hours of overtime in a month died of congestive heart failure after working too much, her employer announced this week.

Miwa Sado was a journalist for Japan’s national public broadcasting organization, NHK, when she died in her home in July 2013, the news outlet said in a statement. Labor authorities later determined Sado’s death was due to “overwork,” according to the Asahi Shimbun newspaper. She had punched in about 159 hours of overtime in the month before her death, NHK said.

High levels of stress can make the heart work harder than it normally does—which, under very rare circumstances, experts say, could potentially lead to death. Here’s what to know about death from overwork.

What does stress do to the heart?

Stress affects everyone differently. But two types of emotional stress can impact the heart, according to Dr. Alan Yeung, the medical director at Stanford Cardiovascular Health. Acute stress usually occurs suddenly after a traumatic event, like a car crash or an earthquake, while chronic stress builds up over time. Unhealthy behaviors, like eating poorly or not exercising, are also linked to chronic stress from working long hours, and these can cause an increase in blood pressure or cholesterol, Yeung said. When a person faces high levels of either kind of stress, their heart rate and blood pressure may increase.

High levels of both types of stress can raise the risk for heart attacks and heart failure, mostly among people who already have heart problems like heart disease, Yeung said.

Heart failure occurs when the heart isn’t pumping as well as it should to deliver the proper amount of oxygen-rich blood to the body’s cells, according to the American Heart Association. More than 6 million Americans have heart failure (symptoms of which can include shortness of breath, chronic coughing, fatigue, nausea, confusion or lack of appetite) and more than 900,000 new cases are diagnosed each year. Anyone can develop heart failure, but it becomes more common with age, and most people who have it tend to have had another heart condition first. It develops over time, and with treatment and drugs, heart failure can often be managed. But without intervention, it can be fatal.

How likely is it to die from working too much?

It’s possible, but very unlikely. Yeung said that heart failure due to stress would probably only be fatal if a variety of factors came together, including a long-simmering period of stress, a sudden stressful situation and potentially an underlying heart condition. “Leading to death, it’s pretty rare,” Yeung said. “Most people hopefully can see a doctor and mitigate it.”

How can it be prevented?

People who have symptoms of a heart condition should immediately seek medical attention, Yeung says. There’s also a lot you can do to manage stress before it becomes a problem. Several known ways to reduce stress include exercising, eating healthy, not smoking, seeking out quiet time and getting support from friends and family.