The sudden heart attack death of Zhang Xuefeng after he collapsed while running in Suzhou, Jiangsu province, triggered a torrent of online searches for heart-related medications, including fast-acting heart pills and nitroglycerin.

JD Health, a large online healthcare platform, found that 30 times more searches for drugs were made (year-on-year), while searches for defibrillators, known as AEDs, and other cardiac monitoring devices increased tenfold. Searches for heart health supplements such as coenzyme Q10 rose more than eightfold.

Zhang, a well-known postgraduate entrance examination tutor died on Tuesday during exercise. He was 41.

Wang Jian, a physician at JD Health Internet Hospital, said that running and other exercise can be a trigger, but is not usually the root cause, of trouble. Risk is greatest for people with underlying heart conditions. Intense running may be an immediate danger, whereas for people with healthy hearts, proper running can be a protective factor.

Wang noted that during vigorous exercise, sympathetic nervous system activation increases heart rate and oxygen demand, and if hidden heart conditions are present, the stress can easily induce irregular heartbeats and sudden death.

To reduce risk, individuals should undergo pre-exercise screening, Wang said. People with recent infections or myocarditis should rest for three to six months, and long-term runners should consider regular electrocardiograms and echocardiograms, which measure such things as heart rhythms and blood flow.

Warning signs requiring an immediate halt of exercise include chest pain, unexplained shortness of breath, dizziness or pale skin with cold sweats. Training intensity should be monitored by keeping the heart rate around 170 minus age, and running should be avoided when sleep-deprived, intoxicated or recovering from a severe illness.

If someone collapses and is unresponsive, bystanders should immediately initiate CPR and use a defibrillator. Without rapid intervention, survival chances decrease by 7 to 10 percent per minute of delay.

For patients with ischemia — restricted blood flow that starves organs and tissues of oxygen — fast-acting heart pills can alleviate some symptoms, but only at the stage of angina, where patients experience chest pain.

Chen Mulei, a physician in the Cardiology Department at Beijing Chaoyang Hospital, Capital Medical University, said the notion that fast-acting heart pills can effectively alleviate a heart attack or stave off death is dubious.

"Once a blood vessel is completely blocked, taking fast-acting heart pills or even nitroglycerin may no longer be effective. For patients with arrhythmias, this type of medication has little therapeutic effect and therefore cannot effectively prevent the occurrence of sudden cardiac death," Chen said.