Effect of rowing ergometry and oral volume loading on cardiovascular structure and function during bed rest
| Autor: | Paul S. Bhella, Benjamin D. Levine, M. Dean Palmer, Qi Fu, Jeffrey L. Hastings, Manish Jain, Eric Pacini, Peter G. Snell, Felix Krainski, Shigeki Shibata |
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| Rok vydání: | 2012 |
| Předmět: |
Male
Cardiac Catheterization Time Factors Physiology medicine.medical_treatment Rowing Echocardiography Three-Dimensional Administration Oral Orthostatic intolerance Bed rest Ventricular Function Left Head-Down Tilt Orthostatic vital signs Deconditioning Exercise Tolerance Models Cardiovascular Articles Stroke volume Middle Aged Magnetic Resonance Imaging Texas Treatment Outcome Fludrocortisone Cardiology Female Weightlessness Countermeasures Compliance medicine.drug Adult medicine.medical_specialty Strength training Cardiomegaly Young Adult Physiology (medical) Internal medicine Ventricular Pressure medicine Humans Plasma Volume Sodium Chloride Dietary Lower Body Negative Pressure Cardiovascular Deconditioning business.industry Myocardium Resistance Training Stroke Volume medicine.disease Orthostatic Intolerance Physical therapy Atrophy business Bed Rest |
| Zdroj: | Journal of Applied Physiology. 112:1735-1743 |
| ISSN: | 1522-1601 8750-7587 |
| DOI: | 10.1152/japplphysiol.00019.2012 |
| Popis: | This study examined the effectiveness of a short-duration but high-intensity exercise countermeasure in combination with a novel oral volume load in preventing bed rest deconditioning and orthostatic intolerance. Bed rest reduces work capacity and orthostatic tolerance due in part to cardiac atrophy and decreased stroke volume. Twenty seven healthy subjects completed 5 wk of −6 degree head down bed rest. Eighteen were randomized to daily rowing ergometry and biweekly strength training while nine remained sedentary. Measurements included cardiac mass, invasive pressure-volume relations, maximal upright exercise capacity, and orthostatic tolerance. Before post-bed rest orthostatic tolerance and exercise testing, nine exercise subjects were given 2 days of fludrocortisone and increased salt. Sedentary bed rest led to cardiac atrophy (125 ± 23 vs. 115 ± 20 g; P < 0.001); however, exercise preserved cardiac mass (128 ± 38 vs. 137 ± 34 g; P = 0.002). Exercise training preserved left ventricular chamber compliance, whereas sedentary bed rest increased stiffness (180 ± 170%, P = 0.032). Orthostatic tolerance was preserved only when exercise was combined with volume loading (−10 ± 22%, P = 0.169) but not with exercise (−14 ± 43%, P = 0.047) or sedentary bed rest (−24 ± 26%, P = 0.035) alone. Rowing and supplemental strength training prevent cardiovascular deconditioning during prolonged bed rest. When combined with an oral volume load, orthostatic tolerance is also preserved. This combined countermeasure may be an ideal strategy for prolonged spaceflight, or patients with orthostatic intolerance. |
| Databáze: | OpenAIRE |
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