Context: Anecdotal reports suggest elite sports clubs combine lower-body positive-pressure rehabilitation with a hypoxic stimulus to maintain or increase physiological and metabolic strain, which are reduced during lower-body positive pressure. However, the effects of hypoxia on cardiovascular and metabolic response during lower-body positive-pressure rehabilitation are unknown. Objective: Evaluate the use of normobaric hypoxia as a means to increase physiological strain during body-weight-supported (BWS) running. Design: Crossover study. Setting: Controlled laboratory. Participants: Seven familiarized males (mean (SD): age, 20 (1) y; height, 1.77 (0.05) m; mass, 69.4 (5.1) kg; hemoglobin, 15.2 (0.8) g·dL−1) completed a normoxic and hypoxic (fraction of inspired oxygen [O2] = 0.14) trial, during which they ran at 8 km·h−1 on an AlterG™ treadmill with 0%, 30%, and 60% BWS in a randomized order for 10 minutes interspersed with 5 minutes of recovery. Main Outcome Measures: Arterial O2 saturation, heart rate, O2 delivery, and measurements of metabolic strain via indirect calorimetry. Results: Hypoxic exercise reduced hemoglobin O2 saturation and elevated heart rate at each level of BWS compared with normoxia. However, the reduction in hemoglobin O2 saturation was attenuated at 60% BWS compared with 0% and 30%, and consequently, O2 delivery was better maintained at 60% BWS. Conclusion: Hypoxia is a practically useful means of increasing physiological strain during BWS rehabilitation. In light of the maintenance of hemoglobin O2 saturation and O2 delivery at increasing levels of BWS, fixed hemoglobin saturations rather than a fixed altitude are recommended to maintain an aerobic stimulus.
Ben J. Lee and Charles Douglas Thake
Yves Eberhard, Jacqueline Eterradossi and Bettina Debû
The effects of exercise and of a physical conditioning program on 11 subjects (7 males, 4 females, aged 15 to 20) with Down’s syndrome (DS) were analyzed. Metabolic responses were evaluated before and after two ergometric cycle exercise tests: an incremental exercise to symptom limited VO2 max. and an endurance test performed at 60% of maximal aerobic power. Plasma substrates, electrolytes, catecholamines, lipoprotein lipid profiles, and superoxide dismutase were assayed immediately before and after these tests. The results indicated (a) a low blood lactate level for peak exercise, (b) slow free fatty acid mobilization at the start of exercise, (c) a low level of cholesterol HDL and a high level of pre-beta VLDL at rest, (d) adjustment to nearly normal lipid profiles with endurance activity, and (e) differences between before and after training for superoxide dismutase levels in subjects with DS. These results suggest that endurance training could have long-term effects on the pathophysiological consequences of DS.
Stephen F. Figoni, Richard A. Boileau, Benjamin H. Massey and Joseph R. Larsen
The purpose of this study was to compare quadriplegic and able-bodied men on selected cardiovascular and metabolic responses to arm-crank ergometry at the same rate of oxygen consumption (V̇O2). Subjects included 11 untrained, spinal cord-injured, C5–C7 complete quadriplegic men and 11 untrained, able-bodied men of similar age (27 years), height (177 cm), and mass (65 kg). Measurement techniques included open-circuit spirometry, impedance cardiography, and electrocardiography. Compared with the able-bodied group, at the V̇O2 of 0.5 L/min, the quadriplegics displayed a significantly higher mean heart rate and arteriovenous O2 difference, lower stroke volume and cardiac output, and similar myocardial contractility. These results suggest that quadriplegic men achieve an exercise-induced V̇O2 of 0.5 L/min through different central cardiovascular adjustments than do able-bodied men. Quadriplegics deliver less O2 from the heart toward the tissues but extract more O2 from the blood. Tachycardia may contribute to low cardiac preload and low stroke volume, while paradoxically tending to compensate for low stroke volume by minimizing reduction of cardiac output.
Jordan Bettleyon and Thomas W. Kaminski
.5007/1980-0037.2011v13n3p189 2. Bangsbo J , Iaia FM , Krustrup P . Metabolic response and fatigue in soccer . Int J Sports Physiol Perform . 2007 ; 2 ( 2 ): 111 – 127 . PubMed ID: 19124899 10.1123/ijspp.2.2.111 19124899 3. Baird M , Graham G , Baker J , Bickerstaff G . Creatine-kinase- and
Jerónimo Aragón-Vela, Yaira Barranco-Ruiz, Cristina Casals-Vázquez, Julio Plaza-Díaz, Rafael A. Casuso, Luis Fontana and Jesús F. Rodríguez Huertas
.F. , Pereira , G.B. , Souza , M.V.C. , Vieira , A. , Marine , D.A. , … Baldissera , V. ( 2012 ). Acute cardiorespiratory and metabolic responses during resistance exercise in the lactate threshold intensity . International Journal of Sports Medicine, 33 ( 2 ), 108 – 113 . PubMed doi:10.1055/s
Natália Barros Beltrão, Camila Ximenes Santos, Valéria Mayaly Alves de Oliveira, André Luiz Torres Pirauá, David Behm, Ana Carolina Rodarti Pitangui and Rodrigo Cappato de Araújo
10. Ratamess NA , Falvo MJ , Mangine GT , Hoffman JR , Faigenbaum AD , Kang J . The effect of rest interval length on metabolic responses to the bench press exercise . Eur J Appl Physiol . 2007 ; 100 ( 1 ): 1 – 17 . PubMed ID: 17237951 doi: 10.1007/s00421-007-0394-y 17237951 11
Maja Zamoscinska, Irene R. Faber and Dirk Büsch
skeleton and causing metabolic response in bone tissue. 38 Aquatic exercises (eg, swimming) or cycling reduce the gravity force affecting the body making them convenient for older adults, but provide no or not enough impact on bone (no impact activity). 8 , 39 , 40 Therefore, these exercises are not
Brandon R. Rigby, Ronald W. Davis, Marco A. Avalos, Nicholas A. Levine, Kevin A. Becker and David L. Nichols
protocols for individuals with PD. To date, the submaximal cardiovascular and metabolic responses to exercise on ATM and AGTM in older adults diagnosed with PD are not known. The purpose of this study was to characterize and compare acute cardiometabolic responses on a traditional LTM, ATM, and AGTM in