European journal of applied physiology
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Eur. J. Appl. Physiol. · Sep 2011
Randomized Controlled TrialArtificial gravity with ergometric exercise as a countermeasure against cardiovascular deconditioning during 4 days of head-down bed rest in humans.
We have shown previously that combined short-arm centrifuge and aerobic exercise training preserved several physiologically important cardiovascular functions in humans. We hypothesized that artificial gravity (AG) and exercise is effective to prevent changes of physical problems during head-down bed rest (HDBR). To test this hypothesis, 12 healthy male subjects had undergone 4 days of 6° HDBR. ⋯ Further, orthostatic tolerance was evaluated by a 75° head-up tilt test and physical working capacity was surveyed by near maximal physical working capacity test before and after bed rest. The data showed that combined centrifuge and exercise applied twice daily for a total of 60 min during 4 days of HDBR prevented (a) a decrease in working capacity, (b) autonomic dysfunction (a decrease in the activity of parasympathetic cardiac innervation) and (c) an increase in leg venous flow resistance. The combination of a 30 min alternating of +1.0 and +2.0 Gz for twice per day of AG with 40 W ergometric exercise may offer a promising countermeasure to short duration simulated microgravity.
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Eur. J. Appl. Physiol. · Sep 2011
Randomized Controlled TrialPleuran (β-glucan from Pleurotus ostreatus) supplementation, cellular immune response and respiratory tract infections in athletes.
Prolonged and exhausting physical activity causes numerous changes in immunity and sometimes transient increases the risk of upper respiratory tract infections (URTIs). Nutritional supplements as countermeasures to exercise-induced changes have increasingly been studied in the last decade. One of the most promising nutritional supplements is β-glucan, a well-known immunomodulator with positive effects on the function of immunocompetent cells. ⋯ In addition, the phagocytosis process remained stable in pleuran group during the study in contrast to placebo group where significant reduction of phagocytosis was observed. These findings indicate that pleuran may serve as an effective nutritional supplement for athletes under heavy physical training. Additional research is needed to determine the mechanisms of pleuran function.
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Eur. J. Appl. Physiol. · Sep 2011
Randomized Controlled TrialNo protective role for hypoxic pulmonary vasoconstriction in severe hypergravity-induced arterial hypoxemia.
Supine subjects exposed to hypergravity show a marked arterial desaturation. Previous work from our laboratory has also shown a paradoxical reduction of lung perfusion in dependent lung regions in supine subjects exposed to hypergravity. We reasoned that the increased lung weight during hypergravity caused either direct compression of the blood vessels in the dependent lung tissue or that poor regional ventilation caused reduced perfusion through hypoxic pulmonary vasoconstriction (HPV). ⋯ In a second phase, 12 supine subjects were exposed to 5 G during three single-blinded conditions; control, after 100 mg sildenafil p.o. and after inhalation of 10 μg iloprost. There was a substantial arterial desaturation by 5-30% units in all subjects with no or only minor differences between conditions. The results speak against HPV as a principal mechanism for the hypergravity-induced reduction of lung perfusion in dependent lung regions in supine humans.
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Eur. J. Appl. Physiol. · Sep 2011
Case ReportsHypothermia following exertional heat stroke treatment.
Exertional heat stroke (EHS) is a life-threatening condition, which deteriorates rapidly. Immediate cooling treatment can, therefore, be life saving. Over the past two winters, we witnessed three cases of hypothermia resulting from treatment of suspected EHS. ⋯ In addition, recommended approaches for proper management of similar situations are discussed. We suggest that in order to avoid hypothermia following aggressive cooling, core temperature (T (core)) should be continuously monitored. Upon reaching 38°C, cooling must be discontinued, and the patient should be dried and covered.