USSR Space Life Sciences Digest, issue 6

This is the sixth issue of NASA's USSR Space Life Sciences Digest. It contains abstracts of 54 papers recently published in Russian language periodicals and bound collections and of 10 new Soviet monographs. Selected abstracts are illustrated with figures and tables from the original. Additional features include a table of Soviet EVAs and information about English translations of Soviet materials available to readers. The topics covered in this issue have been identified as relevant to 26 areas of aerospace medicine and space biology. These areas are adaptation, biospherics, body fluids, botany, cardiovascular and respiratory systems, developmental biology, endocrinology, enzymology, exobiology, genetics, habitability and environment effects, health and medical treatment, hematology, human performance, immunology, life support systems, mathematical modeling, metabolism., microbiology, morphology and cytology, musculoskeletal system, neurophysiology, nutrition, perception, personnel selection, psychology, radiobiology, reproductive biology, and space medicine

Effects of circadian rhythm phase alteration on physiological and psychological variables: Implications to pilot performance (including a partially annotated bibliography)

The effects of environmental synchronizers upon circadian rhythmic stability in man and the deleterious alterations in performance and which result from changes in this stability are points of interest in a review of selected literature published between 1972 and 1980. A total of 2,084 references relevant to pilot performance and circadian phase alteration are cited and arranged in the following categories: (1) human performance, with focus on the effects of sleep loss or disturbance and fatigue; (2) phase shift in which ground based light/dark alteration and transmeridian flight studies are discussed; (3) shiftwork; (4)internal desynchronization which includes the effect of evironmental factors on rhythmic stability, and of rhythm disturbances on sleep and psychopathology; (5) chronotherapy, the application of methods to ameliorate desynchronization symptomatology; and (6) biorythm theory, in which the birthdate based biorythm method for predicting aircraft accident susceptability is critically analyzed. Annotations are provided for most citations

The Impact of Acute and Chronic Weight Restriction and Weight Regulation practices on Physiological, Osteogenic, Metabolic and Cognitive Function in Elite Jockeys

Horse racing is a weight category sport. One of the key challenges facing jockeys is the pressure of “making weight” throughout the protracted racing season. Aim: The aim of this study was to examine the effect of a chronically weight restrictive lifestyle and acute weight loss practices on aspects of physiological, osteogenic, metabolic and cognitive function in jockeys. Methods: The primary aim was achieved through the completion of four related studies. Study One: The effect of a 4% reduction in body mass in 48 hours on physiological and cognitive function was assessed through performance on an incremental cycle ergometer test to volitional exhaustion and a computer based cognitive test battery. Study Two: Bone mass was compared between jockeys (flat and national hunt), elite amateur boxers and a group of age, gender and BMI matched controls. Study Three: Bone mass, bone turnover and endocrine factors related to growth and metabolism were analysed in a group of jockeys and age, gender and BMI matched controls. Study Four: The impact of 6 months whole body vibration therapy (0.3 g and 30 Hz) on bone mass and turnover was analysed in a group of professional jockeys. Results: In study one maximal aerobic exercise performance was negatively affected following a 4% loss in body mass in 48 hours as evidenced by a reduction in peak power output achieved and an increase in submaximal cardiovascular strain. No changes to cognitive performance were identified in this study. In study two both groups of jockeys had lower bone mass at a number of sites than either the boxer or control groups. Adjustment of bone data revealed that differences in height and lean mass accounted for some of the variation between the groups, but that additional factors were present which may have impacted on bone mass in. Study three showed that bone mass was reduced and bone resorption increased in a jockey group. Elevated SHBG and reduced IGF-1 levels in comparison to an age, gender and BMI matched control group appeared to have a role to play in this finding. No aspect of body composition, bone mass or turnover was affected by the vibration therapy protocol used within study four. Conclusion: Results from this research appeared to indicate that aspects of physiological, osteogenic and metabolic function are affected in jockeys. This is likely to have occurred in response to a chronically weight restricted lifestyle. These findings may convey both long and short term health risks to jockeys and as such represent a major health and safety concern to the racing industry

Effect of sleep deprivation on exercise-induced growth hormone release

Growth hormone (GH) is released in a pulsatile fashion from the anterior pituitary gland, with the greatest release occurring during sleep and exercise. Under normal conditions, nocturnal GH release is attenuated during sleep deprivation. Acute sleep deprivation can also impair exercise performance and cognitive function. Therefore, the primary purpose of this study was to assess the impact of acute sleep deprivation on exercise-induced GH release. Secondary aims were to investigate alterations in exercise performance and cognitive function during acute sleep deprivation. Ten male subjects (20.6 ± 1.4 years) were screened for normal sleeping patterns before completing two randomized 24-hour laboratory sessions. They completed a brief, high-intensity exercise bout following either a night of adequate sleep (SLEEP) or acute (24-hour) sleep deprivation (SLD). Anaerobic performance (mean power [MP], peak power [PP], time to peak power [TTPP], minimum power [MinP], fatigue index [FI] and total work per sprint [TWPS]) was determined from four maximal 30-sec Wingate sprints on a cycle ergometer followed by four minutes of active recovery between each sprint. Subjects also performed psychomotor vigilance tasks (PVT) and Paced Auditory Serial Addition Tests (PASAT) during each 24-hr session (0800h, 2000h, 0600h and 0730h) with the latter two taken immediately pre- and post-exercise. The average amount of sleep in the 7 days prior to each session was similar between the SLEEP and SLD sessions (7.92 ± 0.33 vs. 7.98 ± 0.39 hr, p = 0.656, respectively) and during the actual SLEEP session in the lab, the total amount of sleep was similar to the 7 days leading up to the lab session (7.72 ± 0.14 hours vs. 7.92 ± 0.33 hours, respectively) (p = 0.166). Repeated measures analysis of variance (ANOVA) revealed a significant interaction effect of sprint x session on PP (p < 0.05). Only the peak power output during sprint 1 of the SLEEP vs. SLD session was significantly greater (1207 ± 177 vs. 1150 ± 137 W, respectively, p < 0.01). MP, PP, MinP and TWPS decreased significantly within each session (p < 0.01), but there were no significant main effects of session. Respiratory rate (RR) was significantly elevated at rest during the SLD vs. SLEEP session (14.8 ± 2.2 vs. 13.7 ± 3.2 breaths/min, p < 0.05) while heart rate (HR) was significantly depressed at rest (60 ± 8 vs. 64 ± 8 bpm, p < 0.05) and during exercise (176 ± 9 vs. 182 ± 9 bpm, p < 0.05). Average oxygen consumption (VO2), metablic equivalent (METS), expired carbon dioxide (VCO2), ventilation (VE), respiratory exchange ratio (RER), respiratory rate (RR), tidal volume (VT), peak VO2 and peak METS were all similar between sessions. Resting GH concentration and time to reach exercise-induced peak GH concentration were similar between the SLEEP and SLD sessions (0.57 ± 0.13 vs. 1.35 ± 0.55 µg/L, p = 0.575; 29.5 ± 2.2 vs. 27.0 ± 1.5 min, p = 0.257, respectively). However, GH AUC (exercise + recovery), peak GH concentration and ?GH (peak GH – resting GH) were significantly lower during the SLEEP session (p < 0.01). PVT scores post-exercise were significantly poorer during the SLD session (326.2 ± 36.6 vs. 298.8 ± 21.1 msec, p < 0.05). In conclusion, acute sleep deprivation influenced exercise-induced peak HR and GH but had minimal effects on exercise performance. Furthermore, sleep deprivation had no effect on cognitive measures at rest, but did impair sensory sensitivity following exercise

Detection and measurement of stress hormones with mass spectrometry

The purpose of this thesis was to develop and validate a liquid chromatography mass spectrometry (LC-MS) method to measure salivary cortisol and testosterone. Furthermore, to use this method to analyse saliva samples collected during an exercise study measuring the hormonal response to acute exercise. The ongoing contribution to knowledge provided by this research is the application of a developed and validated LC-MS method to analysis of cortisol from pre and post exercise saliva samples, and evaluation of the cortisol and testosterone response to three different training sessions; including an interval session (INT), tempo run (TEMP) and aerobic circuit training (CIR). An LC-MS method was developed to measure cortisol and testosterone. The mass spectrometer used was a triple quadrupole BioQ (Waters/Micromass, UK) coupled with a 1200 series HPLC machine (Agilent Technologies, UK). Optimisation of various parameters was undertaken including: cone voltage and capillary voltage, followed by optimisation of liquid chromatography (LC) parameters such as; mobile phase gradient and flow rate. Saliva samples were collected at rest, and hormones measured with the new LC-MS method and ELISA to validate the developed method. Finally, heart rate and salivary and plasma cortisol and testosterone response to acute exercise were tested, to compare the response to different training protocols in runners. Following this, the MS method underwent further validation against ELISA. Results revealed optimum MS parameters were: cone voltage 25 V; capillary voltage 3.5 kV and LM and HM resolution 8 Da. For the LC method, mobile phase flow rate was optimised at 0.1 mL/min, with a gradient profile ranging from 50 to 95% methanol (MeOH), and a run time of 15 minutes. Sample preparation was also considered (solid phase extraction); and wash phase of 10% MeOH, 10 times sample concentration and reconstitution with 80% MeOH were optimised to improve analyte recovery and detection. Comparison of cortisol measured at rest with LC-MS and ELISA (n=22) revealed a correlation between methods (r=0.83, P<0.001). The exercise study showed the INT elicited a higher peak heart rate (172±11) than CIR (148±10) or TEMP trials (163±10). INT also produced a higher RPE (15 ±2) than CIR (13±1) and TEMP (14±2) trials. Salivary cortisol increased at all time points post exercise in INT and remained higher than rest (1.29 ± 0.51 ng/mL) at 60 minutes recovery (3.13 ±1.59 ng/mL). Salivary testosterone increased pre to post exercise in CIR (119.7±39.5 pg/mL to 150.1 ±51.5 pg/mL), TEMP (142.4±76.5 pg/mL to 185.0±49.1 pg/mL) and INT (117.5±23.5 pg/mL to 176.3±46.0 pg/mL) trials. There was also a correlation between cortisol measured in plasma and saliva (r=0.813, p=0.0001). Additionally, comparison of salivary cortisol measurements obtained with mass spectrometry and ELISA (n=85) showed a correlation (r=0.934, p=00001). In conclusion, validation revealed cortisol could be quantfied accurately and precisely with LC-MS. Additionally, INT elicited a higher mean RPE and cortisol response than TEMP or CIR

Aerospace Medicine and Biology: A continuing bibliography with indexes

This bibliography lists 417 reports, articles and other documents introduced into the NASA scientific and technical information system in March 1985