Up and down make different workouts.

Hiking on a mountainside gives the heart a health-promoting challenge, but the nature of the benefit depends on whether one is climbing or descending. A study conducted on an Alpine mountainside suggests that going up improves the body's processing certain fats, while going down enhances metabolism of a key sugar.

For 2 months of the study, 45 healthy but generally inactive volunteers spent 3 to 5 hours per week scaling the 30-degree slope of a mountain near Feldkirch, Austria, and rode a cable car back down. During a separate 2-month period, they rode up but descended on foot.

Before and after each phase of the study, Heinz Drexel and his colleagues at the Vorarlberg Institute for Vascular Investigation and Treatment in Feldkirch fed the volunteers fatty compounds and the sugar glucose and then measured the hikers' blood concentrations of those substances.

Both up and down hiking softened the spike of blood cholesterol that typically follows fat consumption, the team found. But only uphill exercise improved metabolism of fats called triglycerides, and only downhill exercise significantly increased glucose processing, Drexel says.

Poor glucose metabolism is a feature of diabetes, so the latter finding suggests that downhill exercise--which could include skiing or leaving buildings by the stairs rather than by elevators--could be helpful in preventing or managing that disease, Drexel says.--B.H.