Biomedical subjects

H M Wegmann

Publications and source records attributed to H M Wegmann.

At least 37 records · Page 2Linked to original sources

PubMed1983

A model for prediction of resynchronization after time-zone flights.

Utilizing experimental data from three flight studies, a concept was developed which allows appraising average resynchronization for any day after arrival in a new time-zone. The course of adaptation is nonlinear and can be mathematically represented by an exponential function. The model predicts higher initial resynchronization rates when more time zones are crossed, but total time for complete reentrainment is essentially the same and, thus is independent of the number of time-zones. The equation derived from experimental data is converted into an e-function and the resulting time constants are presented as they evolved for different functions and flight directions.

Aerospace Medicine↗

PubMed1981

Cardiovascular and biochemical response to simulated space flight entry.

Twelve men and 12 women were exposed to two types of short-duration (6 h) space flight entry simulation: bedrest (no head-down tilt) and water immersion (to the neck). Preceding and following the simulation, orthostatic tolerance testing using LBNP (Lower Body Negative Pressure) was performed. Male LBNP tolerance was greater than female LBNP tolerance at all four comparison points (pre- and post-bedrest, pre- and post-water immersion); whereas the short-duration bedrest reduces female LBNP tolerance about as effectively as water immersion, only water immersion leads to marked LBNP intolerance in the male subjects. If the water immersion model simulates zero G, loss of male and female orthostatic tolerance will be about equal after short-duration space flight. On the other hand, the bedrest simulation would indicate a greater loss of orthostatic tolerance for females.

Blood Pressure↗

PubMed1980

Bioinstrumentation for evaluation of workload in payload specialists: results of ASSESS II.

ASSESS II (Airborne Science/Spacelab Experiments System Simulation) was a cooperative NASA-ESA project which consisted of a detailed simulation of Spacelab operations using the NASA Ames Research Center CV-990 aircraft laboratory. The Medical Experiment reported on in this paper was part of the complex payload consisting of 11 different experiments. Its general purpose was to develop a technology, possibly flown on board of Spacelab, and enabling the assessment of workload through evaluating changes of circadian rhythmicity, sleep disturbances and episodical or cumulative stress. As parameters the following variables were measured: Rectal temperature, ECG, sleep-EEG and -EOG, the urinary excretion of hormones and electrolytes. The results revealed evidence that a Spacelab environment, as simulated in ASSESS II, will lead to internal dissociation of circadian rhythms, to sleep disturbances and to highly stressful working conditions. Altogether these effects will impose considerable workload upon Payload Specialists. It is suggested that an intensive pre-mission system simulation will reduce these impairments to a reasonable degree. The bioinstrumentation applied in this experiment proved to be a practical and reliable tool in assessing the objectives of the study.

Adrenal Cortex Hormones↗

PubMed1977

Athletic endurance training - advantage for space flight?: The significance of physical fitness for selection and training of spacelab crews.

While intensive physical exercise has been part of the conditioning of astronauts and consmonauts for spaceflights, its benefits have been questioned. After reviewing the pertinent literature, it is concluded that the morphological and functional changes obtained with athletic endurance training are rather specific and of no general advantage for the tolerance to space stresses. Particularly during gravitational loads, in the relaxed subject, these changes allow a more pronounced shift of fluid into the lower extremities, with the possible consequence of a reduced tolerance. This unfavourable response, obviously, is accentuated through immersion and weightlessness. The aerobic work capacity is also more impaired in athletes. Based on these conclusions, recommendations for crews and passengers of future Spacelab missions are given with respect to selection and pre-and in-flight physical exercise.

Acceleration↗

PubMed1976

Air operations and circadian performance rhythms.

This paper reviews experimental results and pertinent data from the literature on circadian behavioural rhythms and their modifications through various factors. It relates them to the operation of aircrews "round the clock" and on transmeridian routes and discusses some possibilities of an appropriate scheduling.

Aerospace Medicine↗

PubMed1975

[Behavior of the human organism in time zone flights. 2. Sequelae of desynchronization].

The responses of the human organism to time zone flights are reviewed. The physical and biological principles which are connected with dysrhythmic phenomena following shifts of environmental time cues are demonstrated. Quantity and quality of desynchronotic symptoms of psychophysiological functions are described and their significance for performance ability and health of the air traveller, in particular with respect to the possibility of pathogeneous effects, are discussed.

Aerospace Medicine↗

PubMed1975