People who watch Avatar are dazzled by the cool special effects. A huge box-office hit, the 3D film set a record with sales of US$1.8 billion by only its sixth week in theaters. But visually stimulating films of this type do not suit all viewers.

On January 3, a Mr. Guo, 42, attended a screening of Avatar with his family. Half way through, he began to feel physically uncomfortable. By the film's conclusion, he had collapsed in a daze and couldn't sit up straight. Theater employees quickly called an ambulance, but by the time he reached the hospital, he had already lost consciousness and was at five on the Glasgow coma scale. The doctors immediately began to insert tubes for life support and performed an MRI. They discovered that his brain was hemorrhaging. He died 11 days later from the complication of pneumonia.

Strokes affect the body's control center by striking at the arteries to the brain. The after-effects can be very serious and entail a loss of coordination-or even complete paralysis-of the arms and legs. Patients may have to completely relearn simple tasks of everyday living, such as walking, raising arms or grasping objects.

The brain is split into three basic parts-the cerebrum, the cerebellum and the brain stem. These handle such functions as movement, sensory perception, language, memory and balance. The brain is like the hub for executive and life functions in the human body. But why would watching a film cause a stroke?

"When watching a 3D film, your eyes are required to focus for a long time without any breaks. The patient had high blood pressure, and it was easy for ever rising pressure in the skull to cause blood vessels to burst within the skull," explains Lee I-hui, the doctor who treated Mr. Guo at Taipei Veterans General Hospital. "And it was most unfortunate that the hemorrhaging occurred in the pons."

She explains that the pons is part of the brain stem at the back of the brain. It's shaped like a tree trunk, and is about the size of a finger. It connects to the spinal cord, serving a bridge-like function. Inside the pons there are many neurofibrils-the ones at the top responsible for transmitting sensation and the ones at the bottom responsible for transmitting movement. The pons controls such autonomic nervous functions as breathing, swallowing, keeping the heart beating, and regulating the sleep/wake cycle. As soon as hemorrhaging occurs here, a patient will fall into a deep coma with all four limbs paralyzed.

Mr. Guo's stroke was similar to that of Jean-Dominique Bauby, editor-in-chief of the French magazine ELLE, who wrote The Diving Bell and the Butterfly. In 1995, at the age of 44, Bauby, brimming with talent and at the peak of his career, suffered brain hemorrhaging while he was driving his sports car. After he had been in a coma for several months, his condition stabilized, and he could understand what people next to him were saying, but he had no control over his body-apart from being able to blink his left eyelid. Relying on one blink to mean "yes" and two blinks to mean "no," he dictated a 100-page memoir in a year and 10 months that described his feelings of helplessness at his body's imprisonment and the process of how his life was slipping away. Two days after the book was published, he passed away.

Although few have strokes while watching 3D movies, the incident was by no means extraordinary. There have also been news reports about people's carotid arteries bursting when they were riding on roller coasters, massaging their necks with massage pressure sticks, using water columns in spa baths, or having their hair washed in beauty salons. Why do these typical everyday activities potentially cause strokes?

"Blood vessels have two layers: an inner membrane and an outer membrane," explains Yin Jiu-haw, director of the stroke center in the neurology department at Cheng Hsin General Hospital. "They're tightly attached. When there's excessive force from outside, the two membranes may pull apart, so that blood which should have been flowing in the inner membrane leaks out and causes a stroke." Yin emphasizes that these strokes don't just happen to anyone: watching a 3D film and vigorously striking the neck are what trigger the stroke, but the underlying problem is that the victim's arteries have already hardened. The force exerted from outside is just the straw that breaks the camel's back.

Strokes don't just hit the elderly. When young people smoke, have high blood pressure, or spend long hours at their computer screens, not bothering to exercise, their circulation may become impaired, causing their arteries to harden. One should avoid these kinds of behavior.

There are four main arteries that deliver blood from the heart to the brain: the two carotid arteries and the two arteries in the spinal column. If any one of these four arteries or their branches suffers blockages, the brain will lack the blood necessary to perform its functions and will suffer an ischemic stroke (about 70% of all strokes). When arteries rupture as a result of hardening or high blood pressure, it's a hemorrhagic stroke caused by either an intracerebral or a subarachnoid hemorrhage (about 30%).

Among those who suffer strokes, more than 90% are age 50 or older. The older one gets the higher one's chances of suffering a stroke. Because their arteries have hardened or grown narrower, their blood has thickened, and their circulation is weak, those who have had heart attacks or who have high blood pressure or diabetes have a six times greater chance of suffering a stroke than those who do not suffer from those conditions.

Strokes still most commonly afflict older people, but with growing stress in the modern work world and diets based on processed foods and large quantities of oil, sugar, and salt, they have increasingly been hitting the middle-aged. (Taichung Mayor Jason Hu and Kaohsiung Mayor Chen Chu have both had mild strokes). They have even started hitting some people in their thirties.

Dr. Yang Bai-jia, attending physician in the rehabilitation clinic at Mackay Memorial Hospital, collected data on 3,582 stroke patients at the hospital from 2004 to 2006. Among them, those aged 46 and older comprise 94.1%, and those aged 15-45 comprise 5.89%. Analysis of the underlying causes highlights some distinct differences between younger victims and typical stroke patients.

Her research shows that the elderly tend to have arterial blockages (64.9 %), whereas those aged 15-45 tend to have brain hemorrhaging (56.3%) with high blood pressure being the main ultimate cause (62.5%), followed by aneurysms (20.3%), vascular malformation (3.1%), and Heparin-induced thrombocytopenia and hemophilia (1.6%).

Strokes affect the body's control center by striking at the arteries to the brain. The after-effects can be very serious and entail a loss of coordination-or even complete paralysis-of the arms and legs. Patients may have to completely relearn simple tasks of everyday living, such as walking, raising arms or grasping objects.

High blood pressure is regarded as the biggest warning sign of heart disease, kidney disease and strokes. High blood pressure refers to pressure above what is considered normal (140/90 mm Hg). When the pressure in blood vessels is excessive for long periods of time, it results in general damage to organs throughout the body.

According to 2002 figures from the Bureau of Health Promotion, among people over the age of 20 in Taiwan, 24.9% of men and 18.2% of women had high blood pressure. It's troubling that 40% of men with high blood pressure and 20% of women don't even know they have it!

"Early on, high blood pressure has no symptoms, and young office workers often think it's an old person's disease. They often wait until they have splitting headaches, unusual stiffness in the neck, and severe aches and pains-right before the blood vessels are about to rupture. Then they go to a hospital and discover that they have high blood pressure," Yang says.

In addition to being ignorant of their rising blood pressure, young people also tend to eat out and indulge in the on-line world. They can't be bothered to exercise and too easily find themselves suffering from the three health-risk "highs" of modern civilization: high blood pressure, high cholesterol, and high blood sugar (hyperglycemia).

Every year, in the middle of January, data collected from health examinations of new enrollees at universities and colleges are released. This year the number of male freshmen who were overweight had risen to 30%, and the percentages of students with liver problems or high levels of cholesterol or uric acid were also up. Take National Chiao Tung University, for instance. In 2003 1.62% of enrolling freshman had abnormal cholesterol rates; within five years that rate had soared to 11.77%-more than seven times as much. The figure was even higher among those enrolling in doctor's and master's programs: 14.42%. The data is signaling a code-red alarm about the health of Taiwan's younger generation.

"These youth will be at high risk for heart and cardiovascular illnesses," Yang says. As cholesterol accumulates in the blood vessels, the passageways become narrower and narrower, blocking the flow of blood and causing the heartbeat and pulse to speed up and the arteries to harden. Those with high cholesterol are three times as likely to have cardiovascular disease or suffer a stroke.

"Young adults in the prime of their lives are the economic pillars of their families," Yang notes. "When they have strokes, they have to put their careers on hold. And if you estimate that they will have another 20 to 30 years of life, it is quite likely that they will drag their families down economically or even require public assistance. Strokes truly have high social costs." In comparison to hard-to-treat illnesses such as cancer and Parkinson's disease, high blood pressure can be controlled with medication. And by taking medication and changing one's diet to eliminate oily and salty foods, one can prevent strokes. Young people should not treat the situation lightly.

In contrast to cancer, where genetic susceptibility is often paramount, strokes are largely the result of lifestyle choices. To avoid strokes, it's important to pay attention to one's blood pressure, avoid oily foods, and live in a healthy manner.

At any age, those with the "three highs" are at highest risk of a stroke. But among the young the pathology of a stroke is often extremely complex, and requires extensive investigation.

A Ms. Xu, 30, suddenly started to have headaches last year. Her fingers began to feel numb. Slowly, she found it impossible to raise her right arm. Her handwriting became crooked, and it continued until her whole right side lacked strength. First she went to a community hospital near where she lived. The doctor there feared that it was a problem of short-term deficiency of blood to the brain and quickly referred her to a major hospital for tests.

Xu had normal blood pressure, but she did suffer from hyperthyroidism. During the previous 10 years, she had taken her medicine to control the disease, and her condition had been stable, but the sudden paralysis terrified her. There was no clue about the root of the problem. In January she entered Taipei Veterans General Hospital. She had a battery of tests, including an electrocardiogram, an NMR, PET/CT scans, and cerebral angiography. Every day she would wait for the results.

"When a young stroke victim suffers from sudden painful headaches and numbness, it shows that there's a chain reaction going on. You've got to throw a wide net to catch the culprit," analyzes Yin Jiu-haw. Apart from the "three highs," possibilities include arterial and venous aneurysms, abnormal blood clotting factors (such as hemophilia), heart valve damage caused by a combination of congenital heart disease and rheumatic heart disease, and the tetralogy of Fallot, a congenital heart malformation that causes symptoms such as shortness of breath and hypoxia.

A week later, Xu finally had an answer: It was determined that congenital moyamoya disease was at the root of her problem. In x-rays, the collateral cerebral blood vessels of people who suffer from this condition look like a "puff of smoke"-"moyamoya" in Japanese. Those with moyamoya often suffer short-term shortages of blood in the brain along with headaches. In serious cases the large arteries to the brain gradually narrow until they become blocked, leading to paralysis. Generally speaking, after surgery to improve collateral circulation, the odds of reoccurrence are low.

Strokes affect the body's control center by striking at the arteries to the brain. The after-effects can be very serious and entail a loss of coordination-or even complete paralysis-of the arms and legs. Patients may have to completely relearn simple tasks of everyday living, such as walking, raising arms or grasping objects.

Statistics show that the high season for strokes among the elderly is December to February. That's because when the blood vessels contract in the cold weather, the heart needs to exert more effort to pump blood, and the blood pressure naturally rises. During the cold season, there is greater force exerted on the walls of blood vessels, blood pressure increases, and blood vessels are more likely to tear.

But Dr. Yang Bai-jia of Mackay Memorial Hospital researched 227 cases of strokes in that hospital among those aged 15-45 and discovered that among this younger cohort 31.7% had strokes during summer. The other three seasons had roughly equal numbers. It's a seasonal profile quite different from that in the elderly, who tend to have strokes during the fall and winter.

Dr. Yang came to the conclusion that active youngsters are more likely to go out on the town during the summer, since the temperature is higher and there are more hours of daylight. If they fall into one of the high-risk groups-smokers, diabetics, the overweight, or people with high blood pressure or high blood lipids-and they eat and drink with abandon, they may end up pushing their blood pressure too high, causing them to suffer strokes.

Former Taipei Medical University president Hsu Chung-yi, who is a brain expert, hypothetically asks: If you had to choose between cancer, dementia and a stroke, which is the one you'd pick last? Hsu himself answers: a stroke.

Medical advancements, he explains, have brought many new drugs and treatments to battle cancer, and although dementia is tough on families, the sufferers themselves behave like children, living their lives free from worry in their own private world. But those who suffer from strokes may be depressed and tormented in a condition where they lack control of their own bodies. It not only imposes great suffering on themselves and their families but also runs up great medical and rehabilitation expenses that have to be paid by society.

What's more, unlike the other two conditions, where congenital factors are often paramount, people can prevent a high percentage of strokes by changing their behavior. So by all means do your best to eliminate behavior that puts you at risk for strokes!

Strokes don't just hit the elderly. When young people smoke, have high blood pressure, or spend long hours at their computer screens, not bothering to exercise, their circulation may become impaired, causing their arteries to harden. One should avoid these kinds of behavior.