Background: Fatigue is a frequent and severe problem after treatment of patients with hematological malignancies. This symptom has been associated with anemia, reduced physical performance, mood, endocrine disorders and impaired nutritional status. Recently, it has been suggested that fatigue can be related to a persistent activation of the immune system with increased production of proinflammatory cytokines. However, there is no conclusive evidence regarding the role of the immune system in the origin of fatigue in cancer patients. Patients and methods: We evaluated the correlation of fatigue with thyroid function, markers of immune activity [interleukin (IL)-1α, IL-1 soluble receptor, IL-6, C-reactive protein and neopterin], liver and kidney function, mood and physical ability in 71 patients with hematological malignancies. All patients had been free of relapse and not received treatment (chemotherapy, radiotherapy or immune modulators) for at least 3 months. Results: Fatigue was related to depression (r=0.84; P<0.0001) and reduced performance status (r=−0.61; P<0.0001). However, there was no correlation between fatigue and thyroid, liver and kidney function, anemia, albumin concentration or markers of immune activity (all r-values 0.05). Conclusions: We conclude that fatigue in relapse-free patients with hematological malignancies is associated with depressive mood and reduced physical performance, but not with impairment of thyroid function, anemia or persistent activation of the immune system.

The aim of this investigation was to study how the known dependence of working efficiency on pedaling frequency is influenced by the work load as well as by physical fitness. Oxygen uptake, CO₂ output, ventilation, heart rate, and lactate concentration in capillary blood from the ear-lobe were determined at varying combinations of work loads and pedaling rates in road-racing cyclists and medical students. Respiratory exchange ratio, consumption of energy, gross efficiency, net efficiency, and delta efficiency (Δ work rate/Δ metabolic rate) were calculated. All parameters showed a nonlinear dependence on pedaling frequency. The lowest oxygen uptake and the highest efficiency shifted to higher frequencies with increasing work load. Delta efficiency increased with rising pedaling frequency. Differences of V̇O₂ and efficiencies between trained and untrained subjects were only small. Most effects can be explained by variations in leg movement frequency and recruitment of muscle fibers. There is evidence that racing cyclists chose pedaling rates yielding optimal efficiency at any load.

. Methods: Male athletes (N = 90) and untrained male controls (N = 58) were investigated for aerobic performance, hematological parameters, serum erythropoietin concentration (EPO), soluble transferrin receptor concentration (sTFR), and erythrocyte aspartate aminotransferase activity (eAST). Results: On hard floor running disciplines (HFR, N = 26, short- and long-distance runners, triathletes) showed a lower eAST (P < 0.001) and thus no younger RBC population than not on hard floor running athletes (NHFR, N = 64, cyclists, soccer players, others) or the untrained control group (N = 58). HFR had higher but still normal EPO (P < 0.01) and no higher sTFR. Conclusion: Because intravascular hemolysis occurs in swimmers, cyclists, and runners, and mean RBC age is not reduced in runners, mechanisms other than foot-strike hemolysis have to be considered as well. Possible reasons are intramuscular destruction, osmotic stress, and membrane lipid peroxidation caused by free radicals released by activated leukocytes. Intravascular hemolysis can even be regarded as physiological means to provide heme and proteins for muscle growth....

The purpose of our study was to evaluate hematologic acclimatization during 2 weeks of intensive normoxic training with regeneration at moderate altitude (living high-training low, LHTL) and its effects on sea-level performance in well trained athletes compared to another group of equally trained athletes under control conditions (living low - training low, CONTROL). Twenty-one triathletes were ascribed either to LHTL (n = 11; age: 23.0 ± 4.3 yrs; V˙O₂max: 62.5 ± 9.7 [ml × min^-1 × kg^-1]) living at 1956 m of altitude or to CONTROL (n = 10; age: 18.7 ± 5.6 yrs; V˙O₂max: 60.5 ± 6.7 ml × min^-1 × kg^-1) living at 800 m. Both groups perfomed an equal training schedule at 800 m. V˙O₂max, endurance performance, erythropoietin in serum, hemoglobin mass (Hb_tot, CO-rebreathing method) and hematological quantities were measured. A tendency to improved performance in LHTL after the camp was not significant (p < 0.07). Erythropoietin concentration increased temporarily in LHTL (Δ 14.3 ± 8.7 mU × ml^-1; p < 0.012). Hb_tot remained unchanged in LHTL whereas was slightly decreased from 12.5 ± 1.3 to 11.9 ± 1.3g × kg^-1 in CONTROL (p < 0.01). As the reticulocyte number tended to higher values in LHTL than in CONTROL, it seems that a moderate stimulation of erythropoiesis during regeneration at altitude served as a compensation for an exercise-induced destruction of red cells.