Nov. 8, 2004 (New Orleans) -- Results of a randomized, crossover study in sedentary adults suggest that both concentric and eccentric muscle exercise have beneficial effects on lipid and glucose metabolism, suggesting that both walking up and down inclines can be heart healthy.
The study results were discussed at a press conference here at the American Heart Association (AHA) 2004 Scientific Sessions. Lead investigator Heinz Drexel, MD, from the Vorarlberg Institute for Vascular Investigation and Treatment in Feldkirch, Austria, told Medscape that although the study was done in the Alps, a similar exercise benefit "could be achieved by walking up and down several flights of stairs or by using exercise equipment that is designed for both concentric and eccentric workouts."
Dr. Drexel and colleagues randomized 45 healthy, sedentary, nondiabetic volunteers to either two months of hiking up mountains (concentric exercise) or two months of hiking down mountains (eccentric exercise). Participants were instructed to exercise at least three to five times per week. After two months, patients were crossed over to the other exercise program.
When the volunteers hiked up the mountain, they took a cable car down the mountain, and when they hiked down, they took a cable car up. The cable car was useful, said Dr. Drexel, because the researchers used cable car ticket stubs as one measure of compliance. Volunteers were also asked to complete exercise diaries.
At baseline and after each exercise period a full metabolic profile including an oral lipid tolerance test and an oral glucose tolerance test was obtained.
Dr. Drexel said that he and his colleagues expected that only concentric exercise would show benefit, but "the results were surprising. Triglycerides were lowered only by concentric exercise, while glucose tolerance was most improved by eccentric exercise, and both concentric and eccentric improved low-density lipoprotein (LDL) [cholesterol]," he said.
The concentric improvement in the area under the curve for triglyceride levels was 11.0%, which was significant at P = .037. The eccentric improvement in the area under the curve for glucose levels was improved by 8.2% ( P = .027).
Concentric exercise reduced LDL cholesterol levels by 10.2% ( P < .001), and eccentric exercise reduced them by 8.9% ( P = .001), Dr. Drexel said.
Raymond Gibbons, MD, chairman of the AHA scientific program committee, said at the press conference that the study may make him rethink his daily routine. "I regularly walk up the stairs to my office and then take the elevator down. This study suggests that I should change that practice," said Dr. Gibbons, a professor of medicine at the Mayo Clinic in Rochester, Minnesota.
Sidney Smith, MD, director of the Center for Cardiovascular Science and Medicine at the University of North Carolina in Chapel Hill, and a spokesperson for the AHA, told Medscape that the study is interesting but "I would want to know how they did on a flat surface." While Dr. Drexel said the findings suggest that a downhill exercise program might be a good option for people at risk for diabetes or people with type 2 diabetes, Dr. Smith said the evidence of one small study does not support such a recommendation.
AHA 2004 Scientific Sessions: Abstract 3826. Presented Nov. 10, 2004.
Reviewed by Gary D. Vogin, MD
Medscape Medical News © 2004 Medscape
Cite this: Peggy Peck. Both Uphill, Downhill Exercise Help Lipid and Glucose Metabolism - Medscape - Nov 08, 2004.