Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Volume changes in the forearm and lower limbs during 2 h of acute hypobaric hypoxia in nonacclimatized subjects (1997)
    Springer
    European journal of applied physiology 75 (1997), S. 124-131 
    Details
    ISSN: 1439-6327
    Keywords: Key words Altitude  ;  Respiration  ;  Circulation  ;  Fluid distribution  ;  Acclimatization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  To investigate the role of fluid shifts during the short-term adjustment to acute hypobaric hypoxia (AHH), the changes in lower limb (LV) and forearm volumes (FV) were measured using a strain-gauge plethysmograph technique in ten healthy volunteers exposed to different altitudes (450 m, 2500 m, 3500 m, 4500 m) in a hypobaric chamber. Arterial blood pressure, heart rate, arterial oxygen saturation (S aO2), endtidal gases, minute ventilation and urine flow were also determined. A control experiment was performed with an analogous protocol under normobaric normoxic conditions. The results showed mean decreases both in LV and FV of −0.52 (SD 0.39) ml · 100 ml−1 and −0.65 (SD 0.32) ml · 100 ml−1, respectively, in the hypoxia experiments [controls: LV −0.28 (SD 0.37), FV −0.41 (SD 0.47) ml · 100 ml−1]. Descent to normoxia resulted in further small but not significant decreases in mean LV [−0.02 (SD 0.11) ml · 100 ml−1], whereas mean FV tended to increase slightly [ + 0.02 (SD 0.14) ml · 100 ml−1]; in the control experiments mean LV and FV decreased continuously during the corresponding times [−0.19 (SD 0.31), −0.18 (SD 0.10) ml · 100 ml−1, respectively]. During the whole AHH, mean urine flow increased significantly from 0.84 (SD 0.41) ml · min−1 to 3.29 (SD 1.43) ml · min−1 in contrast to the control conditions. We concluded that peripheral fluid volume shifts form a part of the hypoxia-induced acute cardiovascular changes at high altitude. In contrast to the often reported formation of peripheral oedema after prolonged exposure to hypobaric hypoxia, the results provided no evidence for the development of peripheral oedema during acute induction to high altitude. However, the marked increase in interindividual variance in S aO2 and urine flow points to the appearance of the first differences in the short-term adjustment even after 2 h of acute hypobaric hypoxia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004210050136
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Running training and co-ordination between breathing and running rhythms during aerobic and anaerobic conditions in humans (1995)
    Springer
    European journal of applied physiology 70 (1995), S. 387-393 
    Details
    ISSN: 1439-6327
    Keywords: Exercise ; Respiration ; Rhythms co-ordination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The study was carried out on ten triathletes, six sprinters and ten subjects not trained in running (controls) to assess the effects of training history on the co-ordination between breathing and running rhythms during running on a treadmill. Three exercise intensities were used: 50%, 80% and 110% of the subject's anaerobic threshold (AT). All three intensities were performed twice: once with spontaneous breathing and once with breathing intentionally co-ordinated to the running rhythm. Heart rate, respiratory parameters and leg movements were continuously recorded. Blood lactate concentrations were measured discontinuously. The degree of co-ordination between running and breathing was quantified as the percentage of inspirations and/or expirations starting during the same phase of step. The results showed that the degree of both spontaneous and intended co-ordination at aerobic exercise intensities was in all three groups the same and increased in all groups with increasing intensity from 50% to 80% of AT; further increase of intensity to 110% of AT was associated with a significant decrease of co-ordination in controls and sprinters, whereas triathletes were able to maintain the same high degree of co-ordination as at 80% of AT. It was concluded that running training of either type at aerobic work loads had no effect on the co-ordination between running and breathing rhythms. At anaerobic intensities, however, the degree of co-ordination between running and breathing rhythms was higher in the endurance trained athletes than in the sprinters or in the untrained subjects. The degree of co-ordination increased with increasing regularity of breathing. The ability to increase intentionally the degree of co-ordination by paced breathing was independent of running training and was lowest at anaerobic exercise intensities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00618488
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Altitude diuresis: endocrine and renal responses to acute hypoxia of acclimatized and non-acclimatized subjects (1991)
    Springer
    European journal of applied physiology 62 (1991), S. 228-234 
    Details
    ISSN: 1439-6327
    Keywords: Altitude ; Atrial natriuretic peptide ; Arginine vasopressin ; Diuresis ; Cardiac load
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary As a result of our recently published studies we have thought that altitude diuresis resulting from hypoxic stimulation of the arterial chemoreceptors reduces the cardiac volume overload. To test this hypothesis, cardiovascular, endocrine and renal responses to stepwise acute exposure to simulated altitude (6,000 m) were compared in ten acclimatized recumbent mountaineers a mean of 24 days, SD 11, after descending from Himalayan altitudes of at least 4,000 m, with those found in ten non-acclimatized recumbent volunteers. The results showed that natriuresis and diuresis typified the renal responses to altitude exposure of both the acclimatized as well as non-acclimatized subjects, as long as altitude was well tolerated. It was concluded that the renal effects were mediated by atrial natriuretic peptide release and slight suppression of arginine-vasopressin (AVP) secretion, that the increased urine flow at altitude offset the cardiac (volume) overload resulting from hypoxic stimulation of the arterial chemoreceptors, and that enhanced AVP secretion, as found in the non-acclimatized subjects at and above 4,000 m, coincided with subjective and objective distress, i.e. with inadequate altitude adjustment owing to insufficient chemoreflex effects and central hypoxia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00643747
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The effects of acute altitude exposure in swiss highlanders and lowlanders (1993)
    Springer
    European journal of applied physiology 66 (1993), S. 146-154 
    Details
    ISSN: 1439-6327
    Keywords: Hypoxia ; Acclimatization ; Circulation ; Urodilatin ; Respiration ; Neuropsychology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The functional characteristics at rest in responding to stepwise acute exposure to simulated altitude (6000 m) were compared in 10 acclimatized mountaineers (highlanders), residents of Zermatt (1616 m) working at an altitude up to about 4000 m, and in 11 nonacclimatized control subjects (lowlanders) living and working in Zurich (450 m). In comparison with the lowlanders, the highlanders showed at altitude significantly greater hyperventilation, lower heart rate and systolic blood pressure, smaller haemoconcentration, lower urodilatin secretion and natriuresis, and a preserved neuropsychological ability (attentiveness) and vasomotor tone (diastolic blood pressure); the critical altitude at which hypoxic short-term adaptation became insufficient was 6000 m. The lowlanders, however, manifested reduced tolerance of hypoxia, i.e. insufficient short-term adjustment with subjective and objective distress coinciding with the first signs of hypoxia of the central nervous system, already apparent at and above 4000 m. It was concluded that the functional differences between highlanders and lowlanders in responding to acute gradual hypoxia indicated factors contributing to altitude acclimatization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01427056
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Respiratory, circulatory and neuropsychological responses to acute hypoxia in acclimatized and non-acclimatized subjects (1991)
    Springer
    European journal of applied physiology 62 (1991), S. 67-72 
    Details
    ISSN: 1439-6327
    Keywords: Hypoxia ; Acclimatization ; Circulation ; Respiration ; Neuropsychology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Respiratory, circulatory and neuropsychological responses to stepwise, acute exposure at rest to simulated altitude (6,000 m) were compared in ten acclimatized recumbent mountaineers 24 days, SD 11 after descending from Himalayan altitudes of at least 4,000 m with those found in ten non-acclimatized recumbent volunteers. The results showed that hypoxic hyperpnoea and O2 consumption at high altitudes were significantly lower in the mountaineers, their alveolar gases being, however, similar to those of the control group. In the acclimatized subjects the activation of the cardiovascular system was less marked, systolic blood pressure, pulse pressure, heart rate and thus (calculated) cardiac output being always lower than in the controls; diastolic blood pressure and peripheral vascular resistance, however, were maintained throughout in contrast to the vasomotor depression induced by central hypoxia which occurred in the non-acclimatized subjects at and above 4,000 m [alveolar partial pressure of O2 〈 55–50 mmHg (7.3–6.6 kPa)]. It was concluded that in the acclimatized subjects at high altitude arterial vasodilatation and neurobehavioural impairment, which in the non-acclimatized subjects reflect hypoxia of the central nervous system, were prevented; that acclimatization to high altitude resulted in a significant improvement of respiratory efficiency and cardiac economy, and that maintaining diastolic blood pressure (arterial resistance) at and above 4,000 m may represent a useful criterion for assessing hypoxia acclimatization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00626758
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...