Author + information
- Received March 31, 2004
- Revision received May 25, 2004
- Accepted June 7, 2004
- Published online September 15, 2004.
- Tatsiana Suvorava, PhD,
- Nadine Lauer, PharmD, PhD and
- Georg Kojda, PharmD, PhD* ()
- ↵*Reprint requests and correspondence:
Dr. Georg Kojda, Institut fuer Pharmakologie und Klinische Pharmakologie, Heinrich-Heine-Universitaet, Moorenstr. 5, 40225 Duesseldorf, Germany
Objectives We sought to determine if physical inactivity affects endothelial function in young healthy individuals.
Background Recent studies have linked exercise training to increased bioavailability of vascular nitric oxide (NO) and to improved endothelial function in patients with cardiovascular disorders. The effects of physical inactivity on normal vascular endothelial function are not known.
Methods Healthy young male C57Bl/6 mice living in groups of five in large cages, where they were running, climbing, and fighting during their active cycle, were randomly assigned to stay there or to live alone in small cages where they were predominantly resting. After five and nine weeks citrate synthase activity (a measure of mitochondrial respiratory chain activity), heart weight/body weight ratio, vascular reactivity, and protein expression of endothelial nitric oxide synthase (eNOS) were assessed.
Results Singularized mice showed a reduction of citrate synthase activity (p < 0.05), of endothelium-dependent vasorelaxation (to 65 ± 5% of control levels; p < 0.001), and of eNOS protein expression (to 53 ± 8% of control levels; p < 0.01). In striking contrast, vascular responses to potassium chloride, phenylephrine, and the NO-donor racemic S-nitroso-N-acetylpenicillamine were unchanged. The alterations of vascular eNOS-activity were completely reversible when singularized mice underwent exercise. In mice living in groups, exercise showed only a small effect on aortic eNOS expression.
Conclusions In young healthy individuals physical inactivity induces endothelial dysfunction, which is completely reversible by a short period of moderate exercise training. We suggest that physical inactivity, the so-called sedentary lifestyle, increases cardiovascular risk in young healthy individuals by inducing endothelial dysfunction.
This study was supported by the Forschungskommission of the Heinrich-Heine-Universität Düsseldorf (Project 9772 109). The first two authors contributed equally to this work.
- Received March 31, 2004.
- Revision received May 25, 2004.
- Accepted June 7, 2004.
- American College of Cardiology Foundation