Cardiovascular Research Advance Access [Accepted Manuscript] published online on December 1, 2008
Cardiovascular Research, doi:10.1093/cvr/cvn332
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Aerobic interval training vs. continuous moderate exercise in the metabolic syndrome of rats artificially selected for low aerobic capacity
1 Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway
2 Department of Cardiothoracic and Vascular Surgery, University Hospital, North-Norway and Institute of Clinical Medicine, Faculty of Medicine, University of Tromsø
3 Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK
4 Department of Physiology, Pharmacology, Metabolism and Cardiovascular Sciences, University of Toledo, College of Medicine, OH, USA
5 Department of Internal Medicine, Section of Gastroenterology, St. Olavs Hospital, Trondheim, Norway
6 Functional Genomics Laboratory, Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, MI, USA
Correspondence to Ulrik Wisløff, Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Medical Technology Research Centre, Olav Kyrres gate 9, N-7489 Trondheim, Norway. E-mail: ulrik.wisloff{at}ntnu.no Telephone: +4773598638, Fax: +4773598613
Aims: The recent development of a rat model that closely resembles the metabolic syndrome allows for studies of the mechanisms of amelioration of the syndrome by exercise training. Here, we compared the effectiveness for reducing cardiovascular risk factors by exercise training programs of different exercise intensities.
Methods: Metabolic syndrome rats were subjected to either continuous moderate-intensity exercise (CME) or high-intensity aerobic interval training (AIT).
Results: AIT was more effective than CME at reducing cardiovascular disease risk factors linked to the metabolic syndrome. Thus, AIT produced a larger stimulus than CME for increasing maximal oxygen uptake (VO2max; 45% vs. 10%, p<0.01), reducing hypertension (20mmHg vs. 6mmHg, p<0.01), HDL-cholesterol (25% vs. 0%, p<0.05), and beneficially altering metabolism in fat, liver and skeletal muscle tissues. Moreover, AIT had a greater beneficial effect than CME on sensitivity of aorta ring segments to acetylcholine (2.7-fold vs. 2.0-fold, p<0.01); partly because of intensity-dependent effects on expression levels of nitric oxide synthase and the density of caveolae, and a greater effect than CME on the skeletal muscle Ca2+ handling (50% vs. 0%, p<0.05). The two exercise training programs, however, were equally effective at reducing body weight and fat content.
Conclusions: Therefore, high-intensity exercise training was more beneficial than moderate-intensity exercise training for reducing cardiovascular risk in rats with the metabolic syndrome. This was linked to more superior effects on VO2max, endothelial function, blood pressure, and metabolic parameters in several tissues. These results demonstrate that exercise training reduces the impact of the metabolic syndrome and that the magnitude of effect depends on exercise intensity.
KEYWORDS endothelium; metabolism; exercise; hypertension
Time for primary review: 34 Days
# These authors share first authorship
These authors share senior authorship