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John S. Berestka
The Johns Hopkins University School of Medicine Baltimore, Md

JAMA. 1989;262(10):1328.

	Since this article does not have an abstract, we have provided the first 150 words of the full text PDF and any section headings.

To the Editor.—

In his otherwise enlightening editorial "Will Mountain Trekkers Have Heart Attacks?" Dr Rennie¹ contrasts downhill skiing with mountain climbing, trekking, and cross-country skiing and makes the unreferenced statement, "Downhill skiing, where the work is done by the lift, is not an impressive aerobic challenge." The author apparently confuses the classic Newtonian concept of gravitational work (the force of gravity on a given mass mutliplied by the vertical rise) with the medically more pertinent concept of physical work on a cellular level (using adenosine triphosphate to contract muscle by ratcheting actin-myosin cross bridges).

Although alpine ski lifts accomplish the work against gravity in skiing, downhill skiers perform significant aerobic work (through frequent turns and edging maneuvers) to control their gravitational descent as they negotiate trees, gates, moguls, and other skiers. Ericksson² has shown that recreational alpine skiers commonly sustain heart rates of 160 to 170 beats . . . [Full Text PDF of this Article]

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