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
    Rheological modelling of physiological variables during temperature variations at rest (1990)
    Springer
    International journal of biometeorology 34 (1990), S. 76-86 
    Details
    ISSN: 1432-1254
    Keywords: Rheology ; Human ; Heart rate ; Oxygen consumption ; Body temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract The evolution with time of cardio-respiratory variables, blood pressure and body temperature has been studied on six males, resting in semi-nude conditions during short (30 min) cold stress exposure (0°C) and during passive recovery (60 min) at 20°C. Passive cold exposure does not induce a change inHR but increasesVO 2,VCO 2 Ve and core temperatureT re, whereas peripheral temperature is significantly lowered. The kinetic evolution of the studied variables was investigated using a Kelvin-Voigt rheological model. The results suggest that the human body, and by extension the measured physiological variables of its functioning, does not react as a perfect viscoelastic system. Cold exposure induces a more rapid adaptation for heart rate, blood pressure and skin temperatures than that observed during the rewarming period (20°C), whereas respiratory adjustments show an opposite evolution. During the cooling period of the experiment the adaptative mechanisms, taking effect to preserve core homeothermy and to obtain a higher oxygen supply, increase the energy loss of the body.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01093451
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Spectral resolution of cardio-circulatory variations in men measured by autorhythmometry over 2 years (1990)
    Springer
    International journal of biometeorology 34 (1990), S. 105-121 
    Details
    ISSN: 1432-1254
    Keywords: Spectral analysis ; Harmonic analysis ; Unequal sampling ; Cardio-circulatory variables ; Autorhythmometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract An analogue of the periodogram method for unequally spaced data is presented with a view to resolving the frequency structure of the observations. The algorithm is explicitly based on the sequential least squares procedure. In particular, the key concept is that the with-in-plot spectral analysis can be augmented by the between-plot information to make inferences about common characteristics. It is also shown how the between-plot random variations can be incorporated into the multiple harmonic regression model. A detailed spectral analysis investigates the periodic fluctuations in four cardio-circulatory variables, measured by autorhythmometric observation by eight men at rest and extending over a time span of 2 years. The spectral curves show the existence of circadian and circaseptan rhythmicities. The amplitude modulation of the dian rhythm by circaseptan variation is assimilated with the rhythmicity of work during the week. The blood-pressure variables situate their maximum annual peak in the winter period. These quasi-periodic fluctuations appear to be related to the amount of physical activity performed in time by the subjects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01093456
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Cardiac output variations in supine resting subjects during head-out cold water immersion (1995)
    Springer
    International journal of biometeorology 39 (1995), S. 40-45 
    Details
    ISSN: 1432-1254
    Keywords: Cardiac output ; Water ; Cold ; Rest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract Five men, aged 31.2 years (SD 2.3), under semi-nude conditions and resting in a dorsal reclining position, were exposed to thermoneutral air for 30 min, followed immediately by a cold water (15°C) immersion for 60 min. Cardiac output was measured using a dualbeam Doppler flow meter. During immersion in cold water, cardiac frequency (f c) showed an initial bradycardia. The lowest values were reached at about 10 min after immersion, 58.3 (SD 2.5) to 48.3 (SD 7.8) beats min−1 (P 〈 0.05). By the 20th min of exposure,f c had gradually risen to 70.0 beats min−1 (SD 6.6,P 〈 0.05). This change could be due to the inhibition of the initial vagal reflex by increased catecholamine concentration. Stroke volume (V s) was significantly increased (P 〈 0.05) during the whole cold immersion period. Cardiac output, increased from 3.57 (SD 0.50) to 6.26 (SD 1.33)1 min−1 (P 〈 0.05) and its change with time was a function of bothV s andf c. On the other hand, systolic flow acceleration was unchanged during the period of immersion. The changes in the respiratory variables (ventilation, oxygen uptake, carbon dioxide output and respiratory exchange ratio) during immersion showed an initial hyperventilation followed, as immersion proceeded, by a slower metabolic increase due to shivering.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01320892
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Metabolic and hormonal responses during exercise at 20°, 0° and −20°C (1989)
    Springer
    International journal of biometeorology 33 (1989), S. 227-232 
    Details
    ISSN: 1432-1254
    Keywords: Exercise ; Cold ; Lactate ; Catecholamines ; Workload
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract This study was designed to clarify the effects of cold air exposure on metabolic and hormonal responses during progressive incremental exercise. Eight healthy males volunteered for the study. Informed consent was obtained from every participant. The following protocol was administered to each subject on three occasions in a climatic chamber in which the temperature was 20°, 0° or −20°C with relative humidity at 60%±1%. Exercise tests were conducted on an electrically braked ergocycle, and consisted of a propressive incremental maximal exercise. Respiratory parameters were continuously monitored by an automated open-circuit sampling system Exercise blood lactate (LA), free fatty acids (FFA), glucose levels, bicarbonate concentration (HCO 3 − ), acidbase balance, plasma epinephrine (E) and norepinephrine (NE) were determined from venous blood samples obtained through an indwelling brachial catheter. Maximal oxygen uptake was significantly different between conditions: 72.0±5.4 ml kg−1 min−1 at 20°C; 68.9±5.1 ml kg−1 min−1 at 0°C and 68.5±4.6 ml kg−1 min−1 at −20°C. Workload, time to exhaustion, glucose levels and rectal Catecholamines and lactate values were not significantly altered by thermal conditions after maximal exercise but the catecholamines were decreased during rest. Bicarbonate, respiratory quotient, lactate and ventilatory thresholds increased significantly at −20°C. The data support the contention that metabolic and hormonal responses following progressive incremental exercise are altered by cold exposure and they indicate a marked decrease in maximal oxygen uptake, time to exhaustion and workload.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01051082
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Effects of selective cooling of the facial area on physiological and metabolic output during graded maximal or prolonged submaximal exercise (1989)
    Springer
    International journal of biometeorology 33 (1989), S. 82-84 
    Details
    ISSN: 1432-1254
    Keywords: Cold wind ; Exertion ; Lactate ; Work-load
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract Physiological and metabolic output responses to facial cooling during a graded maximal exercise and a prolonged submaximal exercise lasting 30 min at 65% $$\dot VO_2$$ max were investigated in five male subjects. Pedalling on a cycle ergometer was performed both with and without facial cooling (10°C, 4.6 m s−1). Facial cooling at the end of graded maximal exercise apparently had no effect on plasma lactate (LA), maximal oxygen consumption ( $$\dot VO_2$$ max), maximal heart rate (HR max), rectal temperature (T re), work-load, lactate threshold (LT), ventilatory threshold (VT) and onset of blood lactate accumulation (OBLA). However, the response to facial cooling after prolonged submaximal exercise is significantly different for heart rate and work-load. The results suggest that facial wind stimulation during maximal exercise does not produce a stress high enough to alter the metabolic and physiological responses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01686282
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Variations cardio-respiratoires et metaboliques à l'effort sous-maximal (P=40% Pmax) et maximal (Vita Max) en conditions thermiques froide (0 (1986)
    Springer
    International journal of biometeorology 30 (1986), S. 91-106 
    Details
    ISSN: 1432-1254
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Description / Table of Contents: Resume Cette étude a pour but d'étudier les variations physiologiques et métaboliques tant au repos, qu'au cours d'efforts physiques de longue durée (2h) à 40% de la puissance maximale et d'efforts exhaustifs dans des conditions d'hypothermie ambiante (0
    Notes: Abstract The purpose of this study is to investigate the responses on cardiorespiratory and metabolic level measured at rest, during a long-term (2 h) submaximal exercise (P=40% Pmax) and during an exhaustive exercise (Vita Max) and recovery time in normal (20
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02189448
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Hematological variations at rest and during maximal and submaximal exercise in a cold (0°C) environment (1990)
    Springer
    International journal of biometeorology 34 (1990), S. 1-14 
    Details
    ISSN: 1432-1254
    Keywords: Cold ; Hematology ; Cardio-respiratory ; Rest ; Exercise
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Abstract The affect of negative thermal stress on hematological variables at rest, and during submaximal (sub ex) and maximal exercise (max ex) were observed for young males who volunteered in two experimental sessions, performed in cold (0°C) and in normal room temperature (20°C). At rest, hematological variables such as RBC and derivates Hb and Hct were significantly increased (P〈0.05) during cold stress exposure, while plasma volume decreased. The findings of this study suggest that the major factor inducing hypovolemia during low thermal stress can be imputed to local plasma water-shift mechanisms and especially to a transient shift of plasma water from intrato extravascular compartments. Rest values for WBC and platelets (Pla) were also slightly increased during cold stress exposure. However this increase can partly be related to hemoconcentration but also to the cold induced hyperventilation activating the lung circulation. Maximal exhaustive exercise induced, in both experimental temperatures, significant (P〈0.05) increments of RBC, Hb, Hct, and WBC while plasma volume decreased. However, Pla increase was less marked. On the other hand, cold stress raised slightly the observed variations of the different hematological variables. Submaximal exercise induced a similar, though non-significant, pattern for the different hematological variables in both experimental conditions. Observed plasma volume (Δ PV%) reduction appears during exercise. However cold stress induced resting plasma volume variations that are transferred at every exercise level. Neither exercise nor cold inducement significantly modified the hematological indices (MCH, MCV, MCHC). In conclusion hematological variables are affected by cold stress exposure, even when subjects perform a physical activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01045813
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Lactate threshold and onset of blood lactate accumulation during incremental exercise after dietary modifications (1988)
    Springer
    European journal of applied physiology 57 (1988), S. 192-197 
    Details
    ISSN: 1439-6327
    Keywords: Lactate threshold ; Onset on blood lactate accumulation ; Dietary modifications
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study was designed to clarify the effects of dietary modifications on the lactate threshold (LT) and on the onset of blood lactate accumulation (OBLA) during progressive incremental exercise. Six healthy males volunteered for the study. Informed consent was obtained from every participant. The following protocol was administered to each subject on three occasions: a 48-h period of mixed dieting (53% carbohydrates, 30% lipids, 17% proteins) preceding the first exercise test, immediately followed by a 48-h period of either a carbohydrate-rich (68% CHO, 23% lipids, 9% proteins) or a fat-rich (19% CHO, 57% lipids, 26% proteins) iso-caloric diet leading to the second exercise and separated from the third test by a 12-days period. Exercise tests were conducted on an electrically-braked ergocycle, and consisted of a progressive incremental maximal exercise. Respiratory parameters were continuously monitored by an automated open circuit sampling system. Exercise blood lactate (LA), free fatty acids (FFA), glucose levels and acid-base balance were determined from venous blood samples obtained through an indwelling brachial catheter. Peak lactate values, workload and performance time were not significantly altered by imposed diets. Furthermore, dietary modifications had no significant effect on LT, OBLA fixed at 4 mmol and ventilatory threshold. Increased pH and FFA mobilization were observed with fat-rich diet, while CHO-rich diet markedly increased the respiratory exchange ratio (R). It is concluded that LT and OBLA are not significantly altered by fat or CHO enrichment of diets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00640662
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Reversal of cold induced haemoconcentration (1992)
    Springer
    European journal of applied physiology 64 (1992), S. 244-249 
    Details
    ISSN: 1439-6327
    Keywords: Cold ; Haematology ; Urinary excretion ; Cardio-respiratory ; Rest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Classically, cold induced plasma volume reduction is explained by an increased diuresis which is generated by an inhibition of antidiuretic hormone release. However, most of the haemoconcentration appears to be reversible during rewarming. This observation weakens the former statement. The aim of this study was to clarify the mechanisms involved in the reversal of the cold induced haemoconcentration. Six young males, resting in a dorsal reclining position, were exposed successively to a thermoneutral environment (30 min), a cold environment (1° C; cold) or thermoneutrality (control) for 120 min, and during a 60-min recovery period in thermoneutral conditions. During cold stress, a reduction of 15% (i.e. 510 ml) of the plasma volume was observed, and osmolality was unchanged. After the 60-min recovery under thermoneutral conditions, plasma volume variation between the Cold and the Control experiments was reduced and reached 3% (i.e. 100 ml). This volume equalled the increased amount of urine production observed during the cold stress experiment. Haemoconcentration cannot be explained by increased urinary water loss (± 100 ml) alone. Therefore a transient shift of plasma water from vascular to interstitial spaces, due to an increase of blood pressure, could be involved in the reduction of plasma volume.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00626287
    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...