The silent cardiovascular killer – Overwork

The silent cardiovascular killer – Overwork

The silent cardiovascular killer – Overwork



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Death from overwork is a term derived from the Japanese word ‘Karoshi’. In the ‘70s and ‘80s when Japan’s economy took off, the number of sudden death from overexertion and work stress skyrocketed, and ‘Karoshi’ was coined accordingly. To date, Hong Kong is the city with the longest average working hours worldwide and sudden death from overworking is reported from time to time. But why would overworking increase the risk of dying?

How overworking leads to death

A hectic work schedule may result in long-term sleep deprivation and unbearable stresses that would disturb the levels of hormone, electrolyte, cortisol and inflammatory factors, as well as affect our immune system. All these factors may have adverse effects on the blood vessels in our brain and heart. This explains why most deaths from overwork cases were caused by myocardial infarction (acute heart disease) and subarachnoid hemorrhage (cerebral hemorrhage).

Other fatal risks besides overworking

There are other risk factors that could harm our blood vessels including smoking, lack of exercise and a wanton eating and drinking habit. Many research findings also point out that people working night shifts are at an increased risk of developing cardiovascular diseases, simply because a disturbed body clock could lead to a disturbed hormone level.

Sudden death can be congenital?

Research on the causes of sudden death of young people in Hong Kong confirmed that 30% of the deceased and over 50% of their immediate family had genetic mutation of Sudden Arrhythmic Death Syndrome (SADS). SADS is genetic heart conditions, such as congenital irregular heartbeat, that can cause sudden death in young, apparently healthy people regardless of overwork. So we could reasonably infer that if they are really overloaded with work, they would have an even greater chance of dying all of a sudden.

Keep an eye on your physical condition and get a body check regularly

There are SADS warning signals that you should pay attention to, including sudden and unexpected death of a young family member or you experience syncope, chest pain or asthmatic attack while exercising or have a mood swing. Although sudden death may come without warning, you should go for a medical checkup and rest more if you are overworked to the extent that you feel extremely exhausted, scatterbrained, muscle fatigue, dizzy and have a headache, or even become anxious, sleepless and have chest pain.

Case sharing

A man at his 40s passed out with cardiac standstill during a basketball game. Fortunately a passer-by gave him CPR and called the police. He was diagnosed with acute heart disease as 2 out of 3 main blood vessels were blocked. After his coronary bypass operation, his doctor found out that he smoked, drank and worked over 10 hours a day. Recently, he even didn’t sleep for 2 days due to some important work which gave him a headache. Unable to work with pain in his head, he went to play basketball hoping to unwind but didn’t expect that it almost brought him to death.

Dr. Chan Ki Wan, Kelvin, Honorary Clinical Assistant Professor, Department of Medicine, The University of Hong Kong