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Background: Very few studies have been conducted on the effects of simulation of Mars conditions on taste. Aims: This study was planned to find the effects of physical and mental workload on taste sensitivity and salivary stress biomarkers. Materials and Methods: Twelve crew members were selected. Taste reactions and intensity of the taste sensations to quinine sulfate, citric acid, and sucrose were tested before and after mental and physical tasks for one hour. Also, psychological mood states by profile of mood state, salivary, salivary alpha amylase and cortisol, and current stress test scores were measured before and after mental and physical tasks. Results: Average time intensity evaluation showed that after the mental and physical tasks, the perceived duration of bitter, sour, and sweet taste sensations was significantly shortened relative to control group. There were good correlations between average time intensity of sweetness, bitterness, sourness and cortisol levels. Conclusions: Taste alterations due to stress can have an effect on the health and confidence of astronauts in long- term space missions. Thus, this issue remains one of the important issues for future human explorations. [ABSTRACT FROM AUTHOR]

Objective: Wound healing in an extreme environment with microgravity is not well characterized, despite the likelihood that the increasing use of manned spaceflight as a research and commercial enterprise raises the probability of traumatic injury in this state. Hence, this study was conducted to determine the impact of the isolated environment of the Mars Desert Research Station on mucosal immunity and wound healing. Materials and Methods: Two punch biopsy wounds were placed on the hard palate of two crewmembers. The first wound was made during summer vacation, whereas the second was placed on the contralateral side 3 days before the Mars analog mission began. Thus, each crewmember served as his/her own control. Two independent methods were used to assess healing. A ten-item perceived stress scale, salivary cortisol, Immunoglobulin A, IgG and IgM were measured. Results: There were significant differences in the proportion of the wound size healed between vacation and the mission. Salivary IgA, IgM, IgG and cortisol levels showed significant differences between vacation and mission. Conclusion: These data suggest that stress can have significant consequences for wound healing. The effects of stress on wound repair could have important clinical implications, including for recovery from surgery. [ABSTRACT FROM AUTHOR]

Background: Extravehicular activity (EVA), such as exercise performed under unique environmental conditions, is essential for supporting daily living in weightlessness and for further space exploration like long Mars mission. Aim: The study was planned stress, workload, and physiological demands of simulated Mars exploration. Materials and Methods: In this study, the six-person crew lived (24 hours) for 14 days during a short-term stay at the Mars Desert Research Station. The heart rates, salivary cortisol, workload, peak oxygen uptake or maximal aerobic capacity of the crew are measured before, during and after an EVA. Results: Data for heart rate showed the same trend as peak oxygen uptake or maximal aerobic capacity, with a maximal increase to 85% of peak. The rating of subscale showed a significant increase in EVA as compared to run. Salivary cortisol levels and heart rates were increased in both groups, although significant increased of cortisol levels and heart rates more in EVA as compared to hill running crew members. Conclusion: Further study is required on large scale taken into account of limitations of this study and including other physiological and psychological parameters in Mars analog environment. [ABSTRACT FROM AUTHOR]

Spaceflight occurs in an environment of temperature extremes, microgravity, solar and galactic cosmic radiation, lack of atmospheric pressure, and high-speed micrometeorites. Exposure to microgravity and the space environment during space missions of short and long duration has important medical and health implications for astronauts. Psychological well-being is of increasing importance in planned spaceflights and interplanetary missions of long duration. The 6° head-down tilt (HDT) is an established method of mimicking low gravity on earth. The aim of the present study was to determine the effects of 21 days of HDT on psychological stress in 12 healthy male volunteers. Psychological state was assessed by the current stress test, and chromogranin-A (CgA), cortisol, alpha-amylase, and beta-endorphin were measured in saliva. After one week of HDT, all volunteers developed psychological stress, and secretion of CgA, cortisol, alpha-amylase, and beta-endorphin were all significantly higher. Thus, 6° HDT appears to be a valid model to induce psychological stress changes in the immune system, changes that might also be encountered by astronauts and cosmonauts during both a short stay in space, such as that required while orbiting a space station, and in longer spaceflights. [ABSTRACT FROM AUTHOR]