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The primary symptom in patients with chronic heart failure (CHF) is exercise intolerance. Previous studies have reported that reduced exercise tolerance in CHF can be explained not only by cardiac output (a central factor) but also by reduced skeletal muscle aerobic capacity (a peripheral factor). Although exercise training in CHF improves exercise tolerance, few studies have evaluated the effects of exercise training on each specific central and peripheral factor in CHF. The aim of this study was to investigate the central and peripheral aerobic functions in CHF and the effects of exercise training in CHF on cardiac output and skeletal muscle deoxygenation during exercise. We assessed peak oxygen uptake (VO2) during cardiopulmonary exercise testing, peak cardiac output (CO) using noninvasive hemodynamic monitoring, and muscle oxygen saturation (SmO2) using near-infrared spectroscopy (NIRS). Patients with CHF were trained for 12 weeks and performed ramp cycling exercise until exhaustion before and after the exercise training. Peak VO2, peak CO, and SmO2 changes from rest to peak exercise (ΔSmO2) were significantly lower in CHF than those in healthy subjects. As a result of exercise training, peak oxygen uptake in patients with CHF was improved and positively associated with change in ΔSmO2. In contrast, there was no change in peak cardiac output. The results of this study indicate that both cardiac and skeletal muscle functions in patients with CHF were lower than those in healthy subjects. Further, the results suggest that the improvement of exercise capacity in patients with CHF by exercise training was related to the improved utilization of oxygen (a peripheral factor) in skeletal muscle.

The Borg scale rating of perceived exertion is a reliable indicator and widely used to monitor and guide exercise intensity. We aimed to evaluate the relationships between the Borg scale score and oxygenated hemoglobin (O2Hb) and deoxygenated hemoglobin (HHb) concentrations in the leg muscle as measured by near-infrared spectroscopy (NIRS) during cardiopulmonary exercise testing (CPET) in healthy adult men. We also investigated the relationships between the Borg scale score and the work rate (WR), heart rate (HR), oxygen uptake (VO

), and minute ventilation (VE).

Participants comprised 12 healthy men. Cardiopulmonary and NIRS parameters were assessed during each minute of CPET and at the end of the test.

The Borg scale score was significantly correlated with cardiopulmonary parameters including WR, HR, VO

, and VE during CPET (Rs=0.87-0.95; p<0.05). Furthermore, the Borg scale score was significantly correlated with NIRS parameters including O2Hb and HHb levels during CPET (Rs=-0.48 and 0.45, respectively; p<0.05).

The Borg scale score is significantly correlated with cardiopulmonary parameters (WR, HR, VO

, and VE), as well as with leg-muscle oxygenation parameters as assessed by NIRS, during CPET in healthy adults. GSK3 inhibitor The correlation coefficients obtained from NIRS parameters were lower than those of cardiopulmonary parameters.

The Borg scale score might better reflect cardiopulmonary responses than muscle deoxygenation during exercise. These results can aid in the planning of rehabilitation programs for healthy adults.

The Borg scale score might better reflect cardiopulmonary responses than muscle deoxygenation during exercise. These results can aid in the planning of rehabilitation programs for healthy adults.

After hematopoietic stem-cell transplantation (HSCT), patients exhibit decreased muscle strength and muscle oxygen consumption. Furthermore, total corticosteroid dose affects the reduction in muscle strength after HSCT. However, to date, no studies have investigated the relationship between corticosteroid dose and muscle oxygen consumption and saturation in these patients. The purpose of this study was to investigate the relationship between steroid dose and deoxyhemoglobin (ΔHHb) and muscle oxyhemoglobin saturation (ΔSmO

) in patients undergoing HSCT.

This study included 17 men with hematologic disease who underwent allogeneic HSCT. We evaluated ankle dorsiflexor muscle force, ΔHHb, and ΔSmO

in skeletal muscles by near-infrared spectroscopy (NIRS) in patients before and after HSCT.

Peak ankle dorsiflexion, ΔHHb, and ΔSmO

decreased significantly after transplantation as compared to measurements taken before transplantation (p <0.01). The change in peak ankle dorsiflexion from before to after HSCsical exercise in such patients.Continuous noninvasive monitoring of muscle oxygenation has important clinical applications for muscle disorders such as compartmentation syndrome, fibromyalgia, deep vein thrombosis, malignant hyperthermia, and the assessment of training in athletic performance. NIRS has precisely such potential and has been used to detect deep venous thrombosis, evaluate athletic performance, and assess limb reperfusion and revascularization. The aim of this study was to examine the relationship between muscle hemoglobin oxygen (HbO2) and myoglobin (MbO2) desaturation using NIRS combined with venous blood sampling and HbO2 desaturation during forearm muscle exercise. Eleven normal subjects were studied, with informed consent and an IRB-approved protocol. A NIRS sensor (INVOS4100, Somanetics, Corp.) was applied on the volar aspect of the forearm. The subjects exercised their forearm by clenching and relaxing their fist while observing the oximeter and driving the reading to specified levels from 90% to 15% (minimum possible reading). Venous blood samples were withdrawn for measurement of blood gases and oxygen saturation (IL-Co-Oximeter). RSO2 (%) vs VO2 Sat showed a two-component HbO2 desaturation suggesting representation of venous HbO2 desaturation and perhaps myoglobin oxygen (MBO2) desaturation. Subtraction of the linear venous HbO2 curve from the two-component curve suggests MbO2 desaturation at venous hemoglobin oxygen saturation of about 10-20%. Conclusions The kinetics of desaturation during exercise revealed two components representing HbO2 and MbO2 deoxygenation. The data show that MbO2 represents approximately 40% of the NIRS signal and the balance or 60% to HbO2.