Physical training in patients with stable chronic heart failure: Effects on cardiorespiratory fitness and ultrastructural abnormalities of leg muscles
Open accessAbstract
Objectives The present study was designed to evaluate the effect of an ambulatory training program on ultrastructural morphology and the oxidative capacity of skeletal muscle and its relation to central and peripheral hemodynamic variables in patients with chronic heart failure.Background Clinical evidence supports the hypothesis that exercise intolerance in patients with chronic heart failure is not only a consequence of low cardiac output, but is also a result of alterations in oxidative metabolism of skeletal muscle.Methods Twenty-two patients were prospectively randomized either to a training group (mean [+/-SD] ejection fraction 26 +/- 9%, n = 12) participating in an ambulatory training program or to a physically inactive control group (ejection fraction 27 +/- 10%, n = 10). At baseline and after 6 months, patients underwent symptom-limited bicycle exercise testing, and central and peripheral hemodynamic variables were measured. Percutaneous needle biopsy samples of the vastus lateralis muscle were obtained at baseline and after 6 months. The ultrastructure of skeletal muscle was analyzed by ultrastructural morphometry.Results After 6 months, patients in the training group achieved an increase in oxygen uptake at the ventilatory threshold of 23% (from 0.86 +/- 0.2 to 1.07 +/- 0.2 liters/min, p < 0.01 vs. control group) and at peak exercise of 31% (from 1.49 +/- 0.4 to 1.95 +/- 0.4 liters/min, p < 0.01 vs. control group). There was no significant change in oxygen uptake at the ventilatory threshold and at peak exercise in the control group. The total volume density of mitochondria and volume density of cytochrome c oxidase-positive mitochondria increased significantly by 19% (from 4.7 +/- 1.5 to 5.6 +/- 1.5 vol%, p < 0.05 vs. control group) and by 41% (from 2.2 +/- 1.0 to 3.1 +/- 1.0 vol%, p < 0.05 vs. control group) after 6 months of regular physical exercise. Cardiac output at rest and at submaximal exercise remained unchanged but increased during maximal symptom-limited exercise from 11.9 +/- 4.0 to 14.1 +/- 3.3 liters/min in the training group (p < 0.05 vs. baseline; p = NS vs. control group). Peak leg oxygen consumption increased significantly by 45% (from 510 +/- 172 to 740 +/- 254 ml/min, p < 0.01 vs. control group). Changes in cytochrome c oxidase-positive mitochondria were significantly related to changes in oxygen uptake at the ventilatory threshold (r = 0.82, p < 0.0001) and at peak exercise (r = 0.87, p < 0.0001).Conclusions Regular physical training increases maximal exercise tolerance and delays anaerobic metabolism during submaximal exercise in patients with stable chronic heart failure. Improved functional capacity is closely linked to an exercise-induced increase in the oxidative capacity of skeletal muscle.
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In both HFpEF and HFrEF, the peripheral contributions to improved peak VO2 with training appear to be attributable largely to improved skeletal muscle function.
“In both patients with HF with preserved ejection fraction and those with HFrEF, the peripheral contributions to improved peak V˙o2 with training appear to be attributable largely to improved skeletal muscle function (ie, increased percent skeletal muscle oxidative fibers, mitochondrial volume density, oxidative capacity, capillarity, and muscle blood flow).204–206”
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Cites
Anaerobic threshold and respiratory gas exchange during exercise.
Wasserman, K., Whipp, B. J., Koyl, S. N., & Beaver, W. L. (1973) · Journal of Applied Physiology · doi:10.1152/jappl.1973.35.2.236 · Cited by 2,093 · see citing works
Adaptations of skeletal muscle to endurance exercise and their metabolic consequences
Holloszy, J. O., & Coyle, E. F. (1984) · Journal of Applied Physiology · doi:10.1152/jappl.1984.56.4.831 · Cited by 1,985 · see citing works
A questionnaire for the assessment of leisure time physical activities
Taylor, H. L., Jacobs, D. R., Schucker, B., Knudsen, J., Leon, A. S., & Debacker, G. (1978) · Journal of Chronic Diseases · doi:10.1016/0021-9681(78)90058-9 · Cited by 1,848 · see citing works
Franciosa, J. A., Park, M., & Levine, T. B. (1981) · The American Journal of Cardiology · doi:10.1016/0002-9149(81)90286-1 · Cited by 878 · see citing works
Alterations of skeletal muscle in chronic heart failure.
Drexler, H., Riede, U. N., Münzel, T. F., König, H., Funke, E., & Just, H. (1992) · Circulation · doi:10.1161/01.cir.85.5.1751 · Cited by 780 · see citing works
Self-citationEndothelium-dependent vasodilation is attenuated in patients with heart failure.
Kubo, S. H., Rector, T. S., Bank, A. J., Williams, R. E., & Heifetz, S. M. (1991) · Circulation · doi:10.1161/01.cir.84.4.1589 · Cited by 775 · see citing works
MANCINI, D. M., Walter, G., Reichek, N., Lenkinski, R. E., McCully, K. K., Mullen, J. L., & Wilson, J. R. (1992) · Circulation · doi:10.1161/01.cir.85.4.1364 · Cited by 736 · see citing works
Cardiovascular Adaptations to Physical Training
Blomqvist, C. G., & Saltin, B. (1983) · Annual Review of Physiology · doi:10.1146/annurev.ph.45.030183.001125 · Cited by 706 · see citing works
Sullivan, M. J., Higginbotham, M. B., & Cobb, F. R. (1988) · Circulation · doi:10.1161/01.cir.78.3.506 · Cited by 697 · see citing works
Skeletal muscle biochemistry and histology in ambulatory patients with long-term heart failure.
Sullivan, M. J., Green, H. J., & Cobb, F. R. (1990) · Circulation · doi:10.1161/01.cir.81.2.518 · Cited by 689 · see citing works
Endurance training in humans: aerobic capacity and structure of skeletal muscle.
Hoppeler, H., Howald, H., Conley, K., Lindstedt, S. L., Claassen, H., Vock, P., & Weibel, E. R. (1985) · Journal of Applied Physiology · doi:10.1152/jappl.1985.59.2.320 · Cited by 623 · see citing works
Endothelin in human congestive heart failure.
Wei, C., Lerman, A., Rodeheffer, R. J., McGregor, C. G. A., Brandt, R. R., Wright, S., Heublein, D. M., Kao, P.-C., Edwards, W. D., & Burnett, J. C. J. (1994) · Circulation · doi:10.1161/01.cir.89.4.1580 · Cited by 585 · see citing works
Correlates and prognostic implication of exercise capacity in chronic congestive heart failure
Szlachcic, J., Masse, B. M., Kramer, B. L., Topic, N., & Tubau, J. F. (1985) · The American Journal of Cardiology · doi:10.1016/0002-9149(85)90742-8 · Cited by 498 · see citing works
The ultrastructure of the normal human skeletal muscle
Hoppeler, H. H., L�thi, P., Claassen, H., Weibel, E. R., & HOWALD, H. (1973) · Pflügers Archiv - European Journal of Physiology · doi:10.1007/bf00588462 · Cited by 444 · see citing works
Effects of physical training in chronic heart failure
Coats, A. J. S. (1990) · The Lancet · doi:10.1016/0140-6736(90)90536-e · Cited by 443 · see citing works
Clausen, J. P. (1976) · Progress in Cardiovascular Diseases · doi:10.1016/0033-0620(76)90012-8 · Cited by 438 · see citing works
Hambrecht, R., Niebauer, J., Marburger, C., Grunze, M. F., Kälberer, B., Hauer, K. A., Schlierf, G., Kübler, W., & Schuler, G. (1993) · Journal of the American College of Cardiology · doi:10.1016/0735-1097(93)90051-2 · Cited by 427 · see citing works
Self-citationMANCINI, D. M., Coyle, E. F., Coggan, A. R., Beltz, J., Ferraro, N., Montain, S. J., & Wilson, J. R. (1989) · Circulation · doi:10.1161/01.cir.80.5.1338 · Cited by 389 · see citing works
Physical training improves skeletal muscle metabolism in patients with chronic heart failure
Adamopoulos, S. N., Coats, A. J. S., Brunotte, F., Arnolda, L., Meyer, T. E., Thompson, C. H., Dunn, J. F., Stratton, J. R., Kemp, G. J., Radda, G. K., et al. (1993) · Journal of the American College of Cardiology · doi:10.1016/0735-1097(93)90231-o · Cited by 384 · see citing works
Alterations in vasomotor tone in congestive heart failure
ZELIS, R. F., & Flaim, S. F. (1982) · Progress in Cardiovascular Diseases · doi:10.1016/0033-0620(82)90012-3 · Cited by 365 · see citing works
Corral‐Debrinski, M. (1991) · JAMA · doi:10.1001/jama.266.13.1812 · Cited by 341 · see citing works
Massie, B. M., Conway, M. A., Yonge, R., Frostick, S. P., Ledingham, J. G. G., Sleight, P., Radda, G. K., & Rajagopalan, B. (1987) · Circulation · doi:10.1161/01.cir.76.5.1009 · Cited by 339 · see citing works
Wiener, D. H., Fink, L. I., Maris, J., Jones, R. A., Chance, B., & Wilson, J. R. (1986) · Circulation · doi:10.1161/01.cir.73.6.1127 · Cited by 300 · see citing works
Sullivan, M. J., Higginbotham, M. B., & Cobb, F. R. (1989) · Circulation · doi:10.1161/01.cir.79.2.324 · Cited by 298 · see citing works
Higginbotham, M. B., Morris, K. G., Conn, E. H., Coleman, R. E., & Cobb, F. R. (1983) · The American Journal of Cardiology · doi:10.1016/s0002-9149(83)80010-1 · Cited by 291 · see citing works
Effect of exercise and training on mitochondria of rat skeletal muscle
Gollnick, P., & King, D. S. (1969) · American Journal of Physiology-Legacy Content · doi:10.1152/ajplegacy.1969.216.6.1502 · Cited by 280 · see citing works
Massie, B. M., Conway, M. A., Rajagopalan, B., Yonge, R., Frostick, S. P., Ledingham, J. G. G., Sleight, P., & Radda, G. K. (1988) · Circulation · doi:10.1161/01.cir.78.2.320 · Cited by 268 · see citing works
Exertional fatigue due to skeletal muscle dysfunction in patients with heart failure.
Wilson, J. R., MANCINI, D. M., & Dunkman, W. B. (1993) · Circulation · doi:10.1161/01.cir.87.2.470 · Cited by 223 · see citing works
Skeletal muscle response to exercise training in congestive heart failure.
Minotti, J. R., Johnson, E. C., Hudson, T. L., Zuroske, G., Murata, G., Fukushima, E., Cagle, T. G., Chick, T. W., Massie, B. M., & Icenogle, M. V. (1990) · Journal of Clinical Investigation · doi:10.1172/jci114771 · Cited by 204 · see citing works
Effects of detraining on responses to submaximal exercise
Coyle, E. F., Martin, W. H., Bloomfield, S. A., Lowry, O. H., & Holloszy, J. O. (1985) · Journal of Applied Physiology · doi:10.1152/jappl.1985.59.3.853 · Cited by 174 · see citing works
Direct measurement of skeletal muscle fatigue in patients with chronic heart failure.
Buller, N. P., Jones, D. A., & Poole‐Wilson, P. A. (1991) · Heart · doi:10.1136/hrt.65.1.20 · Cited by 172 · see citing works
Training-Induced Morphological and Functional Changes in Skeletal Muscle
HOWALD, H. (1982) · International Journal of Sports Medicine · doi:10.1055/s-2008-1026053 · Cited by 156 · see citing works
Ehsani, A. A., Biello, D. R., Schultz, J., Be, S., & Holloszy, J. O. (1986) · Circulation · doi:10.1161/01.cir.74.2.350 · Cited by 155 · see citing works
Hemodynamic Determinants of Exercise Capacity in Chronic Heart Failure
MYERS, J. N., & Froelicher, V. F. (1991) · Annals of Internal Medicine · doi:10.7326/0003-4819-115-5-377 · Cited by 142 · see citing works
Blomstrand, E., & Ekblom, B. T. (1982) · Acta Physiologica Scandinavica · doi:10.1111/j.1748-1716.1982.tb07163.x · Cited by 135 · see citing works
Hagberg, J. M., Ehsani, A. A., & Holloszy, J. O. (1983) · Circulation · doi:10.1161/01.cir.67.6.1194 · Cited by 131 · see citing works
Functional and structural adaptations in skeletal muscle of trained athletes
Alway, S. E., MacDOUGALL, J. D., SALE, D. G., Sutton, J. R., & McComas, A. J. (1988) · Journal of Applied Physiology · doi:10.1152/jappl.1988.64.3.1114 · Cited by 127 · see citing works
Neurophysiological assessment of skeletal muscle fatigue in patients with congestive heart failure.
Minotti, J. R., Pillay, P., Chang, L., et al. (1992) · Circulation · doi:10.1161/01.cir.86.3.903 · Cited by 95 · see citing works
Hambrecht, R., Schuler, G. C., Muth, T., Grunze, M. F., Marburger, C., Niebauer, J., Methfessel, S., & Kübler, W. (1992) · The American Journal of Cardiology · doi:10.1016/0002-9149(92)91265-6 · Cited by 89 · see citing works
Self-citationEffect of training/detraining on submaximal exercise responses in humans
Moore, R. L., Thacker, E. M., Kelley, G., Musch, T. I., Sinoway, L. I., Foster, V. L., & DICKINSON, A. L. (1987) · Journal of Applied Physiology · doi:10.1152/jappl.1987.63.5.1719 · Cited by 58 · see citing works
The concentration of the Na,K-pump in skeletal and heart muscle in congestive heart failure
Nørgaard, A., Bjerregaard, P., Baandrup, U. T., et al. (1990) · International Journal of Cardiology · doi:10.1016/0167-5273(90)90032-z · Cited by 50 · see citing works
Sullivan, M. J., Binkley, P. F., Unverferth, D. V., et al. (1985) · Journal of Clinical Investigation · doi:10.1172/jci112148 · Cited by 48 · see citing works
Perotti, M. E., Anderson, W. A., & Swift, H. H. (1983) · Journal of Histochemistry & Cytochemistry · doi:10.1177/31.3.6186730 · Cited by 47 · see citing works
Riede, U. N., & Reith, A. (1980) · Medical Entomology and Zoology · Cited by 34 · see citing works
Self-citationHemodynamic and metabolic responses of the exercising lower limb of humans.
Sullivan, M. J., Pk, B., Unverferth, D. V., et al. (1987) · PubMed · Cited by 29 · see citing works
Neuroendocrine activation in congestive heart failure
Forfar, J. C. (1991) · The American Journal of Cardiology · doi:10.1016/0002-9149(91)90065-s · Cited by 16 · see citing works
Minotti, J. R., & Dudley, G. (1993) · Current Opinion in Cardiology · doi:10.1097/00001573-199305000-00005 · Cited by 7 · see citing works
Coexistence of skeletal muscle abnormalities in cardiomyopathy
Benditt, D. G., Dunnigan, A., Milstein, S., et al. (1989) · Journal of the American College of Cardiology · doi:10.1016/0735-1097(89)90384-7 · Cited by 7 · see citing works
Corral-Debrinski, M. (1991) · JAMA · doi:10.1001/jama.1991.03470130092035 · Cited by 1 · cited 1× · see citing works
“3) Mutations of mitochondrial deoxyribonucleic acid (DNA) due to excessive accumulation of free radicals induced by recurrent episodes of hypoxemia and reperfusion may account for intrinsic alterations in skeletal muscle of patients with chronic heart failure (41).”
Background
Flagged first, then by citations
Research works printed but not linked: 2
- Weickcr H. Bestimung der freien und konjugierten Katecholamine mit HPLC unter amperometrischer Dctektion. Lab Med 1986;33:122 32.
- Forfar JC. Ncuroendocrine activation in chronic heart failure. Am J Cardiol 1991;67:3C 15C.
Cited by
Sorted by citations
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Pedersen, B. K., & Saltin, B. (2015) · Scandinavian Journal of Medicine & Science in Sports · doi:10.1111/sms.12581 · Cited by 3,514 · see citing works
WRITING COMMITTEE MEMBERS, Hunt, S. A., Abraham, W. T., Chin, M. H., Feldman, A. M., Francis, G. S., Ganiats, T. G., Jessup, M., Konstam, M. A., Mancini, D. M., et al. (2005) · Circulation · doi:10.1161/circulationaha.105.167586 · Cited by 2,251 · see citing works
Fletcher, G. F., Ades, P. A., Kligfield, P., Arena, R., Balady, G. J., Bittner, V. A., Coke, L. A., Fleg, J. L., Forman, D. E., Gerber, T. C., et al. (2013) · Circulation · doi:10.1161/cir.0b013e31829b5b44 · Cited by 2,235 · see citing works
O'Connor (2009) · doi:10.1001/jama.2009.454 · Cited by 2,173 · see citing works
Fletcher, G. F., Balady, G. J., Amsterdam, E. A., Chaitman, B., Eckel, R., Fleg, J., Froelicher, V. F., Leon, A. S., Piña, I. L., Rodney, R., et al. (2001) · Circulation · doi:10.1161/hc3901.095960 · Cited by 1,923 · see citing works
Evidence for prescribing exercise as therapy in chronic disease
Pedersen, B. K., & Saltin, B. (2006) · Scandinavian Journal of Medicine & Science in Sports · doi:10.1111/j.1600-0838.2006.00520.x · Cited by 1,384 · see citing works
Fletcher, G. F., Balady, G., Blair, S. N., Blumenthal, J., Caspersen, C., Chaitman, B., Epstein, S., Froelicher, E. S. S., Froelicher, V. F., Pina, I. L., et al. (1996) · Circulation · doi:10.1161/01.cir.94.4.857 · Cited by 1,319 · see citing works
Belardinelli, R., Georgiou, D., Cianci, G., & Purcaro, A. (1999) · Circulation · doi:10.1161/01.cir.99.9.1173 · Cited by 1,099 · see citing works
Piña, I. L., Apstein, C. S., Balady, G. J., Belardinelli, R., Chaitman, B. R., Duscha, B. D., Fletcher, B. J., Fleg, J. L., Myers, J. N., & Sullivan, M. J. (2003) · Circulation · doi:10.1161/01.cir.0000055013.92097.40 · Cited by 1,030 · see citing works
Hambrecht, R. (2000) · JAMA · doi:10.1001/jama.283.23.3095 · Cited by 689 · see citing works
Self-citationHambrecht, R., Fiehn, E., Yu, J., Niebauer, J., Weigl, C., Hilbrich, L., Adams, V., Riede, U., & Schuler, G. (1997) · Journal of the American College of Cardiology · doi:10.1016/s0735-1097(97)00015-6 · Cited by 386 · see citing works
Self-citationHaykowsky, M. J., Brubaker, P. H., Stewart, K. P., Morgan, T. M., Eggebeen, J., & Kitzman, D. W. (2012) · Journal of the American College of Cardiology · doi:10.1016/j.jacc.2012.02.055 · Cited by 358 · see citing works
McKelvie, R. S., Teo, K. K., Roberts, R., McCartney, N., Humen, D., Montague, T., Hendrican, K., & Yusuf, S. (2002) · American Heart Journal · doi:10.1067/mhj.2002.123310 · Cited by 322 · see citing works
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Rees, K., Taylor, R. R., Singh, S., Coats, A. J., & Ebrahim, S. (2004) · Cochrane Database of Systematic Reviews · doi:10.1002/14651858.cd003331.pub2 · Cited by 253 · see citing works
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Fleg, J. L. (2007) · Heart Failure Clinics · doi:10.1016/j.hfc.2007.07.016 · Cited by 2 · see citing works
- Authors
- Hambrecht, R., Niebauer, J., Fiehn, E., Kälberer, B., Offner, B., Hauer, K., Riede, U., Schlierf, G., Kübler, W., & Schuler, G.
- Affiliations
- St. Vincentius-Kliniken (DE)
- Heidelberg University (DE)
- University of Freiburg (DE)
- Corresponding author
- Hambrecht, Rainer
- Venue
- Journal of the American College of Cardiology
- Publisher
- Elsevier BV
- Published
- 1995-05
- Volume
- 25
- Issue
- 6
- Pages
- 1239-1249
- ISSN
- 0735-1097 (ISSN-L)
- OpenAlex
- W2064296725
- Cited by
- 580
- References
- 49
- Citations by year
- 2026: 5 · 2025: 8 · 2024: 8 · 2023: 13 · 2022: 6 · 2021: 11 · 2020: 11 · 2019: 21 · 2018: 17 · 2017: 14 · 2016: 20 · 2015: 18 · 2014: 17 · 2013: 19 · 2012: 19
- FWCI
- 54.69
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Licence
- Locations
- Journal of the American College of Cardiology (publishedVersion)
- PubMed (publishedVersion)
- FreiDok plus (Universitätsbibliothek Freiburg) (submittedVersion)
- Funders
- Deutsche Forschungsgemeinschaft
- Topics
- Health Sciences › Medicine › Complementary and alternative medicine › Cardiovascular and exercise physiology
- Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Heart Failure Treatment and Management
- Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Cardiac Health and Mental Health
- Keywords
- chronic heart failure, exercise training, cardiorespiratory fitness, skeletal muscle ultrastructure, mitochondrial density, cytochrome c oxidase, oxidative metabolism, exercise intolerance, oxygen consumption, cardiac output, hemodynamics, vastus lateralis, exercise capacity, ejection fraction, exercise-induced cardiomyopathy, exercise-induced arrhythmia
- MeSH terms
- Biopsy, Catecholamines, Echocardiography, Energy Metabolism, Exercise Test, Exercise Therapy, Femoral Vein, Heart Failure, Hemodynamics, Humans, Leg, Male, Middle Aged, Mitochondria, Oxygen Consumption, Physical Education and Training, Prospective Studies, Regional Blood Flow, Exercise Tolerance, Muscle, Skeletal
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