Each summer, reports of lone walkers and climbers found dead in isolated spots baffle doctors and relatives who are left to grieve without any explanation of what can have caused the death. Now experts from the lightning data centre in Denver, US, have studied a case in which lightning killed without leaving a mark.
Four golfers were sheltering under a tree during a thunderstorm when it was struck by a bolt of lightning. One of the golfers, a 32-year-old man, collapsed with a heart attack. A doctor who happened to be nearby gave him artificial resuscitation before the man was taken to hospital but he died without regaining consciousness 18 days later.
Of the remaining three golfers, one had superficial burns on his head, neck and abdomen and the other two were knocked unconscious for a short time but were otherwise unhurt. The man who died had no burn marks on him to suggest he had been struck by lightning.
Dr Michael Cherington and colleagues suggest in a letter to The Lancet that the cause of his death may have been the intense electromagnetic discharge of the lightning passing close by which induced a current in his body sufficient to stop his heart. They say: "The lightning may induce a loop current within the human torso without evidence of current entering the body. If these currents occur during a vulnerable part of the cardiac cycle, they could cause asystole [stopped heart beat] or ventricular fibrillation [an often fatal abnormal heart rhythm]."
The authors suggest that the mechanism "may explain some unwitnessed and unexplained `heart attacks' among hikers who are found dead in the mountains".
Weather forecasters advise that the most important thing to remember when caught in a thunderstorm is not to be the tallest object around. One said: "If you find yourself in a wide open field the best advice is to lie down. It is very unwise to shelter under a tree."Reuse content