Stress, long hours and an unhealthy lifestyle can have serious, even terminal, consequences. Liu Zhihua reports.

Shi Wenxiong, a 41-year-old from Beijing, says he only survived a heart attack three years ago because he was lucky.

One morning in September 2008, Shi, a manager at Shunyi Gardening Service Center of Beijing, went to work as usual but when he arrived, he started having heart palpitations and felt unwell.

He had been having similar problems for three months so he just ignored them.

He then realized something was seriously wrong when his left arm went numb.

He lost consciousness while driving to the hospital, but was lucky enough to get picked up by a passerby who took him to hospital.

"Without him, I would have died," Shi says. "I was so ignorant. I almost worked myself to death."

Doctors at Anzhen Hospital, a leading hospital treating cardiovascular diseases, diagnosed him as having acute myocardial infarction.

Commonly known as a heart attack, it is one of the five most prevalent types of coronary heart disease caused by atherosclerosis, in which the artery walls thicken due to accumulation of fats.

In recent years headlines saying that someone has died of heart diseases or stroke, resulting from overwork, have become common.

"People don't die because of too much work, rather they die because they neglect the signs (of illness). They are deprived of life by diseases accelerated by overwork, such as heart attack or stroke," says Yuan Biao, a heart disease specialist at Huaxin Hospital in Beijing.

The root cause of those diseases, Yuan says, is atherosclerosis.

"When atherosclerosis develops, fats and cholesterol stick to the walls of blood vessels and form plaque that impedes blood flow," says Miao Lifu, another cardiologist at Huaxin Hospital.

"When the plaque ruptures and eventually induces thrombus formation in the lumen, the arteries and the smaller downstream branches may get blocked, causing interruption of blood supply to related organs and thus lead to death of organ cells."

Atherosclerosis can occur in any part of the body. When it happens in arteries around the heart and brain, the damage is life threatening.

"It never dawned on me that I was having a heart attack. My family has no heart disease history, and I didn't think my lifestyle would lead to health problems," Shi says.

Experts say the principal cause of atherosclerosis is unclear, but risk factors include family history, gender, smoking, drinking alcohol, psychological stress and physical exertion.

While factors such as advanced age and a genetic disposition are beyond one's control, high blood pressure and lipid levels can be reined in.

Before his heart attack, Shi worked around the clock, supervising construction sites and socializing.

From early 2007, landscaping and gardening to prepare Beijing for the 2008 Olympic Games, caused him to work even harder.

He slept just five hours a day, sometimes in his car on construction sites. He smoked continuously, he admits.

Apart from the physical exhaustion, he was also under acute mental pressure. If he had free time he would play poker all night, as a form of escape.

Shi had no idea that he was practically killing himself.

"Continuous overwork brings about physical and mental stress, which have a comprehensive impact on the whole body," says Jia Haizhong, a cardiovascular disease specialist with China-Japan Friendship Hospital in Beijing.

"On the one hand (physical and mental stress) sharply weaken the body's immunity, while on the other, when the body reacts in a stressful way, dysfunction of the autonomic nervous system throughout the body will occur."

If the situation continues, the blood sugar and cholesterol metabolism will be disturbed and blood pressure will rise, which ultimately increases the likelihood of atherosclerosis, and other problems.

Li Gen, a 25-year-old at a Beijing-based commercial bank, is living in the shadow of daily stress.

His work requires him to be highly focused and as a result he finds it hard to relax after work. He has been suffering from insomnia since May.

"Whenever I lie down, various thoughts creep into my mind and develop, and I also hear sounds in my ears," Li says.

He usually manages just two to three hours of sleep a night.

Since August, his stomach has been feeling uncomfortable after meals and he often gets stomachaches.

Li knows the problem is work related stress and realizes he needs to deal with this psychologically.

Jia opines Li's symptoms are typical physical responses to long-term mental stress.

Stress strains the body and affects the autonomic nervous system, making it overactive.

Stress is also one of the most common causes of a sudden elevated blood pressure.

Adequate sleep, a good mood, proper exercise, and low salt and fat diets, are vital for those who have high blood pressure, says Ma Changsheng, a cardiologist at Anzhen Hospital.

In Li's case, blood and oxygen supply to the stomach is impeded, affecting the normal chemical reactions in the stomach and harming the gastrointestinal mucous membrane.

Eventually, this could lead to ulcers and perhaps gastrorrhagia (stomach bleeding).

"Rest and relaxation are extremely important," Jia says.

As for Shi Wenxiong, he understands this better than he did. He now lives a lifestyle he never dreamed he would adopt.

He jogs regularly, eats healthily, has quit smoking, drinking and gambling, and most importantly, works less.

"Nothing is more important than health," Shi says. "When you feel you need rest, just rest."