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Aerobic interval training effectively enhances cardiac hemodynamic response to exercise in HFrEF patients while increasing the delivery/use of O2 to exercising skeletal muscles and frontal cerebral lobe tissues in HFpEF patients, thereby improving global/disease-specific quality-of-life measures in these HF patients.

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. Effects of normoxic and hypoxic exercise regimens on cardiac, muscular, and cerebral hemodynamics suppressed by severe hypoxia in humans. J Appl Physiol 109: 219-229, 2010. First published April 29, 2010 doi:10.1152/japplphysiol.00138.2010.-Hypoxic preconditioning prevents cerebrovascular/cardiovascular disorders by increasing resistance to acute ischemic stress, but severe hypoxic exposure disturbs vascular hemodynamics. This study compared how various exercise regimens with/without hypoxia affect hemodynamics and oxygenation in cardiac, muscle, and cerebral tissues during severe hypoxic exposure. Sixty sedentary males were randomly divided into five groups. Each group (n ϭ 12) received one of five interventions: 1) normoxic (21% O 2) resting control, 2) hypoxic (15% O2) resting control, 3) normoxic exercise (50% maximum work rate under 21% O 2; N-E group), 4) hypoxic-relative exercise (50% maximal heart rate reserve under 15% O2; H-RE group), or 5) hypoxicabsolute exercise (50% maximum work rate under 15% O 2; H-AE group) for 30 min/day, 5 days/wk, for 4 wk. A recently developed noninvasive bioreactance device was used to measure cardiac hemodynamics, and near-infrared spectroscopy was used to assess perfusion and oxygenation in the vastus lateralis (VL)/gastrocnemius (GN) muscles and frontal cerebral lobe (FC). Our results demonstrated that the H-AE group had a larger improvement in aerobic capacity compared with the N-E group. Both H-RE and H-AE ameliorated the suppression of cardiac stroke volume and the GN hyperemic response (⌬total Hb/min) and reoxygenation rate by acute 12% O2 exposure. Simultaneously, the two hypoxic interventions enhanced perfusion (⌬total Hb) and O 2 extraction [⌬deoxyHb] of the VL muscle during the 12% O2 exercise. Although acute 12% O2 exercise decreased oxygenation (⌬O2Hb) of the FC, none of the 4-wk interventions influenced the cerebral perfusion and oxygenation during normoxic/ hypoxic exercise tests. Therefore, we conclude that moderate hypoxic exercise training improves cardiopulmonary fitness and increases resistance to disturbance of cardiac hemodynamics by severe hypoxia, concurrence with enhancing O2 delivery/utilization in skeletal muscles but not cerebral tissues.oxygen; physical activity; circulation CHRONIC INTERMITTENT HYPOXIA is known to enhance aerobic capacity by increasing pulmonary ventilation, adaptation of the hematopoetic system, and tissue utilization of O 2 in sedentary males (43, 44), endurance athletes (10, 13), and elderly subjects with or without vascular diseases (8). Animal studies have also indicated that hypoxic preconditioning reduced the volume of cerebral infarction and edema (41) and attenuated the loss of myocardial contractility (3) immediately after sublethal ischemic insult. Therefore, we speculate that increased O 2 delivery/utilization and resistance to acute hypoxic/ischemic stresses conferred by hypoxic interventions improves exercise performance and is effective for preventing and treating cerebrovascular/cardiovascular diseases.Howeve...

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This investigation elucidated the underlying mechanisms of functional impairments in patients with heart failure (HF) by simultaneously comparing cardiac-cerebral-muscle hemodynamic and ventilatory responses to exercise among HF patients with various functional capacities. One hundred one patients with HF [New York Heart Association HF functional class II (HF-II, n = 53) and functional class III (HF-III, n = 48) patients] and 71 normal subjects [older control (O-C, n = 39) and younger control (Y-C, n = 32) adults] performed an incremental exercise test using a bicycle ergometer. A recently developed noninvasive bioreactance device was adopted to measure cardiac hemodynamics, and near-infrared spectroscopy was employed to assess perfusions in the frontal cerebral lobe (Δ[THb](FC)) and vastus lateralis muscle (Δ[THb](VL)). The results demonstrated that the Y-C group had higher levels of cardiac output, Δ[THb](FC), and Δ[THb](VL) during exercise than the O-C group. Moreover, these cardiac/peripheral hemodynamic responses to exercise in HF-III group were smaller than those in both HF-II and O-C groups. Although the change of cardiac output caused by exercise was normalized, the amounts of blood distributed to frontal cerebral lobe and vastus lateralis muscle in the HF-III group significantly declined during exercise. The HF-III patients had lower oxygen-uptake efficiency slopes (OUES) and greater Ve-Vo(2) slopes than the HF-II patients and age-matched controls. However, neither hemodynamic nor ventilatory response to exercise differed significantly between the HF-II and O-C groups. Cardiac output, Δ[THb](FC), and Δ[THb](VL) during exercise were directly related to the OUES and Vo(2peak) and inversely related to the Ve-Vco(2) slope. Moreover, cardiac output or Δ[THb](FC) was an effect modifier, which modulated the correlation status between Δ[THb](VL) and Ve-Vco(2) slope. We concluded that the suppression of cerebral/muscle hemodynamics during exercise is associated with ventilatory abnormality, which reduces functional capacity in patients with HF.

The COronaVIrus Disease 2019 (COVID-19), which developed into a pandemic in 2020, has become a major healthcare challenge for governments and healthcare workers worldwide. Despite several medical treatment protocols having been established, a comprehensive rehabilitation program that can promote functional recovery is still frequently ignored. An online consensus meeting of an expert panel comprising members of the Taiwan Academy of Cardiovascular and Pulmonary Rehabilitation was held to provide recommendations for rehabilitation protocols in each of the five COVID-19 stages, namely (1) outpatients with mild disease and no risk factors, (2) outpatients with mild disease and epidemiological risk factors, (3) hospitalized patients with moderate to severe disease, (4) ventilator-supported patients with clear cognitive function, and (5) ventilator-supported patients with impaired cognitive function. Apart from medications and life support care, a proper rehabilitation protocol that facilitates recovery from COVID-19 needs to be established and emphasized in clinical practice.