Analytical comparison of physiological parameters in participants during an analog space mission

1 Introduction

Long-duration human missions are associated with exposure to a complex combination of physiological and psychological stressors, including isolation, confinement, altered circadian rhythms, restricted physical activity, and limited environmental variability. These factors are known to influence cardiovascular regulation, thermoregulation, metabolic balance, and autonomic nervous system activity, even in the absence of microgravity or radiation exposure (Foucher et al., 2021; Carrière et al., 2022; Snook and Mendell, 2004; NASA, 2020). Understanding the magnitude and variability of these responses is essential for improving health monitoring strategies during long-duration missions and for refining experimental designs in space-related research. Due to the limited availability of in-flight biomedical data, terrestrial analog environments play a crucial role in investigating human responses to isolation and confinement. Analog missions allow controlled observation of physiological and behavioral changes under reproducible conditions and have been widely used in space medicine research (Gangale, 2017; Riva et al., 2022; Gronwald BJ. et al., 2022). Studies conducted in facilities such as Mars500, HI-SEAS, and Antarctic research stations including Concordia and Vostok have demonstrated that prolonged isolation may influence cardiovascular function, sleep regulation, thermoregulation, and psychological wellbeing, although the magnitude of these effects varies considerably across individuals and mission durations (Perchonok and Bourland, 2002; Gronwald B. et al., 2022; Silva-Espinoza et al., 2020; Oeland et al., 2010; Reckelhoff, 2018; Smith et al., 2020). Importantly, terrestrial analogs are not intended to replicate spaceflight in its entirety. Rather, they model selected stressors most notably confinement, social isolation, and structured daily routines that are common to both analog missions and long-duration spaceflight. In this context, analog studies provide valuable insight into inter-individual variability and short-term physiological stability under controlled environmental conditions (Navarro-Ledesma et al., 2022; Barnett et al., 2007; Kuht and Farmery, 2021; Saeki et al., 2014). Despite increasing interest in analog research, available studies remain heterogeneous with respect to study design, monitoring frequency, and measured outcomes. Many investigations rely on relatively small sample sizes and limited observation periods, which restricts the ability to draw conclusions regarding physiological adaptation or long-term health effects (Hill et al., 2023; Christiansen et al., 2007; Iqbal et al., 2023; Winterton et al., 2020). Furthermore, basic physiological parameters such as body weight, blood pressure, heart rate, body temperature, and oxygen saturation although routinely collected are often interpreted without sufficient consideration of confounding factors such as hydration status, physical activity, circadian influences, or environmental variability (Holt-Lunstad et al., 2015; Long et al., 2023; Richard et al., 2017; Hom et al., 2017). Previous investigations conducted in long-term isolation environments, particularly in Antarctic stations such as Concordia and Vostok, have demonstrated that physiological responses to confinement evolve over time and may differ substantially between short-term and long-term exposure (O’Riordan et al., 2023; Jia et al., 2019; Di Angelantonio et al., 2016; Bangash et al., 2022; Sondej and Zawadzka, 2022). These studies highlight the importance of distinguishing between transient physiological variability and true adaptive or maladaptive responses. The present study was designed as a descriptive observational investigation conducted during a 14-day isolated analog mission at the LunAres Research Station. The study does not aim to simulate spaceflight conditions such as microgravity or radiation exposure. Instead, it focuses on assessing short-term physiological responses to isolation and confinement in healthy adult participants under controlled terrestrial conditions. By characterizing changes in body weight, core body temperature, blood pressure, heart rate, and peripheral oxygen saturation, and by examining inter-individual variability across the mission duration, this study aims to contribute to a better understanding of physiological stability during short-term isolation. The findings are intended to support the methodological refinement of future analog studies and to provide context for interpreting physiological data obtained in longer and more complex mission scenarios.

2 Aim of the study

The aim of this study was to descriptively assess changes in selected physiological parameters in healthy adult participants during a 14-day isolated analog mission conducted under controlled terrestrial conditions.

Specifically, the study sought to:

• characterize temporal changes in body weight, core body temperature, systolic and diastolic blood pressure, heart rate, and peripheral oxygen saturation;
• evaluate inter-individual variability of these parameters during short-term isolation;
• assess the feasibility and limitations of routine physiological monitoring in a confined analog environment.

This investigation was designed as an observational study and was not intended to model spaceflight physiology or to assess causal mechanisms of physiological adaptation. The focus was placed on descriptive analysis of physiological stability under isolation conditions rather than on hypothesis testing or prediction of long-term health outcomes.

3 Materials and methods

3.1 Research setting

The study was conducted at the LunAres Research Station in Piła, Poland, a terrestrial space analog facility designed to simulate conditions relevant to future lunar and Martian missions. The station was specifically developed to reproduce key characteristics of Integrated, Confined, and Extreme (ICE) environments. The habitat consists of a central research area connected to modular units, including living quarters, laboratory space, a gym, and a kitchen.

Throughout the 14-day mission, the facility remained fully isolated from the external environment, with no access to natural light or fresh air. Ambient temperature was maintained at a constant level of 21 °C ± 1 °C. Illumination was provided by a fully automated LED lighting system programmed to simulate a standard 16:8 light–dark cycle, thereby supporting circadian entrainment despite the absence of natural zeitgebers.

3.2 Study design

The present study was designed as a prospective observational investigation conducted during a 14-day isolated analog mission at the LunAres Research Station. The study aimed to document changes in selected physiological parameters under conditions of confinement and controlled environmental exposure.

No experimental intervention was applied. The study was not intended to simulate spaceflight physiology, nor to investigate causal mechanisms of physiological adaptation. Instead, it focused on descriptive monitoring of physiological responses to isolation, which represents a key stressor common to long-duration missions.

The study followed a non-interventional design, and all analyses were descriptive in nature.

3.3 Participants

A total of 40 healthy adult volunteers (21 females and 19 males) were enrolled in the study across multiple independent 14-day isolation sessions. All participants underwent medical screening prior to inclusion to confirm eligibility for participation in a confined environment. Long-term smoking status was not used as an inclusion or exclusion criterion. However, all participants were required to maintain complete nicotine abstinence throughout the isolation mission. No chronic medication use was reported during the study period.

3.3.1 Inclusion criteria

• Age between 20 and 50 years,
• Absence of diagnosed cardiovascular, metabolic, or neurological disorders,
• No acute illness at the time of inclusion,
• Ability to comply with isolation and monitoring protocols.

3.3.2 Exclusion criteria

• Failure to meet medical clearance requirements,
• Withdrawal of informed consent,
• Protocol non-compliance,
• Incomplete physiological data,
• Technical or operational issues affecting data integrity.

All enrolled participants completed the mission and were included in the final analysis. No exclusions were related to adverse medical events. Written informed consent was obtained from all participants prior to enrollment. Two individuals were excluded from the final analysis of body temperature data due to technical measurement artifacts; however, the full cohort (n = 40) was retained for all other physiological parameters.

3.4 Description of the research setting and environmental conditions

The study was conducted during a 14-day isolated analog mission at the LunAres Research Station, a terrestrial analog facility designed to reproduce selected operational and psychosocial aspects of long-duration space missions. The facility enables controlled investigation of human responses to confinement, isolation, restricted external communication, and structured daily routines, which are recognized as key stressors in long-duration spaceflight analog research.

The general external view of the LunAres habitat is presented in Figure 1, while the internal spatial organization and functional layout of the station are shown in Figure 2.

3.4.1 Analog environment characteristics

The LunAres habitat is a closed, self-contained facility in which participants remain fully isolated from the external environment for the duration of the mission. All daily activities including work, rest, meals, and scientific tasks are performed entirely within the habitat.

It is important to emphasize that the facility does not simulate microgravity or cosmic radiation exposure. Atmospheric pressure, oxygen concentration, and gravitational load remained within normal terrestrial ranges throughout the study. Consequently, the present investigation should be interpreted as an isolation and confinement analog, rather than a direct simulation of orbital or planetary spaceflight.

The primary scientific value of the LunAres environment lies in its ability to reproduce:

• Prolonged social and sensory isolation,
• Restricted living space,
• Limited privacy,
• Structured operational schedules,
• Sustained separation from external environmental cues.

These conditions represent core stressors common to long-duration missions and are widely used in analog research.

3.4.2 Environmental conditions

Environmental parameters within the habitat were maintained within predefined operational ranges throughout the mission. These included:

• Ambient temperature, maintained within a stable indoor range suitable for prolonged habitation,
• Relative humidity, controlled to avoid extreme fluctuations,
• Artificial lighting, following a fixed light dark cycle,
• Acoustic and visual isolation, with minimal external stimuli.

Although the environment was controlled, minor day-to-day variations in temperature, humidity, and workload were unavoidable and are acknowledged as potential contributors to physiological variability.

The overall spatial organization of the habitat, including living quarters, working areas, and EVA simulation zones, is illustrated in Figure 2.

3.4.3 Operational conditions and daily routine

Participants followed a structured daily schedule consisting of:

• Mission-related operational tasks,
• Scientific and technical activities,
• Standardized meals based on freeze-dried food rations,
• Designated rest periods.

To preserve ecological validity, the protocol allowed limited flexibility in daily activities. Consequently:

• Physical activity was not strictly standardized,
• Exercise intensity was not quantitatively monitored,
• Sleep onset and wake times were not rigidly enforced.

This approach reflects realistic operational conditions in analog missions but is acknowledged as a limitation when interpreting physiological variability.

3.4.4 Scope and limitations of environmental simulation

The present study was not designed to replicate the full spectrum of spaceflight stressors. In particular:

• Microgravity effects were not simulated,
• Ionizing radiation exposure was absent,
• No artificial atmospheric modification was applied.

Therefore, the observed physiological responses should not be interpreted as spaceflight-induced adaptations. Instead, they reflect responses to isolation, confinement, and altered daily structure, which are common features of both terrestrial analog missions and long-duration spaceflight.

3.4.5 Implications for data interpretation

The environmental characteristics of the LunAres habitat provide a valid framework for examining:

• Short-term physiological responses to confinement,
• Inter-individual variability under isolated conditions,
• Feasibility of physiological monitoring protocols in analog missions.

At the same time, the absence of strict environmental and behavioral standardization limits causal interpretation. Accordingly, the results should be considered descriptive rather than mechanistic, and interpreted in conjunction with the methodological constraints outlined above.

3.5 Study protocol and daily routine

Participants followed a structured daily schedule that included:

• Mission-related operational tasks,
• Scientific and maintenance activities,
• Standardized meals based on freeze-dried food rations,
• Designated rest periods.

Physical activity was not standardized and was not quantitatively monitored. Exercise equipment was available but use was voluntary. Sleep timing followed the imposed day–night cycle but was not strictly controlled. No pharmacological interventions were permitted during the mission unless medically indicated.

3.6 Measurement protocol and equipment physiological measurements

All physiological measurements were conducted daily during the morning hours, typically between 07:00 and 09:00 a.m., in accordance with the standardized daily schedule implemented within the habitat. Measurements were performed after participants had completed their morning hygiene routine and consumed a standardized breakfast, as well as following a brief daily planning discussion outlining scheduled activities.

Although measurements were not obtained in a strict fasting state, they were consistently collected within the same circadian phase and before the onset of planned operational tasks and structured exercise, thereby minimizing the influence of diurnal variability and acute physical exertion.

The following physiological parameters were assessed:

• Body Weight: Measured using a Beurer GS 203 digital scale (Beurer GmbH, Ulm, Germany) with a precision of 0.1 kg. Participants were weighed in light clothing and without footwear,
• Core Body Temperature: Assessed using a non-contact infrared thermometer (Visiomed ThermoFlash LX-26; Visiomed Group, Paris, France) with measurements taken at the temporal artery. Readings below 32.0 °C were either cross-validated using a secondary digital thermometer or classified as artifacts resulting from improper sensor positioning and excluded from further analysis. systolic blood pressure (SBP),
• Blood Pressure (SBP/DBP) and Heart Rate (HR): Measured using an automated oscillometric sphygmomanometer (Omron M3 Comfort; Omron Healthcare, Kyoto, Japan). In accordance with standard clinical guidelines, participants were instructed to remain seated and relaxed for at least 5 min prior to measurement. heart rate (HR),
• Oxygen Saturation (SpO₂): Measured using a finger pulse oximeter (Beurer PO 30; Beurer GmbH, Ulm, Germany) placed on the index finger.

Participants were instructed to abstain from caffeine consumption and vigorous physical activity for at least 30 min prior to all measurements.

Measurements were performed at three predefined time points:

• Day 1 (baseline),
• Day 7,
• Day 14.

All measurements were obtained using the same calibrated equipment throughout the mission. Participants were assessed in a seated position following a short rest period. Measurement timing was not strictly standardized within the daily schedule, which is acknowledged as a limitation. Body composition (e.g., fat mass, lean mass, hydration status) was not assessed; therefore, changes in body weight should be interpreted with caution.

3.7 Standardized routine and physical activity

Dietary intake was standardized with respect to food type. Participants had access exclusively to freeze-dried meals provided by LyoFood, which were prepared according to the manufacturer’s instructions by rehydration with a specified volume of water. Although total caloric intake was not strictly controlled, restricting food sources to a uniform category of products reduced dietary variability related to macronutrient composition and food processing.

All participants were required to consume a minimum of 2 L of water per day to ensure adequate hydration. This requirement was particularly relevant given the freeze-dried nature of the diet, which necessitates rehydration prior to consumption and may increase daily fluid demands. These procedures reflect standard practices in spaceflight analog missions, where hydration monitoring is considered a critical component of crew health maintenance.

Physical activity during the mission was not enforced as a mandatory protocol. Participants were encouraged to engage in daily movement and moderate physical activity according to individual preference and perceived wellbeing, reflecting natural behavioral patterns under conditions of confinement and isolation. The habitat was equipped with basic exercise facilities, including a treadmill and resistance bands; however, their use was voluntary.

A central principle of the protocol was the prioritization of participant safety and wellbeing. In the event of adverse symptoms such as weakness, headache, gastrointestinal discomfort, or general malaise either in the morning or during physical activity participants were instructed to immediately discontinue exercise and rest. Consequently, physical activity could be reduced or omitted entirely on a given day if required.

This flexible, symptom-driven approach was intended to preserve operational realism consistent with crewed spaceflight and space-analog missions, in which scheduled exercise may be modified or suspended in response to crew health status.

3.8 Statistical analysis

Statistical analyses were performed using Statistica software, version 13.3 (TIBCO Software Inc., Palo Alto, CA, USA). Due to the non-normal distribution of several variables, as confirmed by Q–Q plot inspection, non-parametric statistical methods were applied. Given the limited sample size and low temporal resolution, inferential statistical modeling was not emphasized. Due to deviations from normality observed for several parameters, inferential testing was limited and results were interpreted descriptively. Pairwise comparisons between Day 1, Day 7, and Day 14 were conducted using the Wilcoxon signed-rank test. Inter-individual variability was assessed using quantile analysis, skewness, and kurtosis. Statistical significance was set at p < 0.05. Despite some deviations from the normal distribution, differences in the measured characteristics were examined using the repeated-measures Student’s t-test with Holm’s correction for multiple comparisons. Therefore, p values should be considered approximate. No causal inferences were drawn from the data. Individual trajectory graphs for parameters were used.

3.9 Ethical considerations

The study was conducted in accordance with the Declaration of Helsinki. Ethical approval was obtained from the Bioethics Committee of the Pomeranian Medical University (approval no. KB-0012/105/18).

All participants provided written informed consent prior to participation. The study involved non-invasive physiological monitoring only and did not include experimental medical interventions.

4 Results

4.1 Study population

A total of 40 participants completed the 14-day isolation mission and were included in the final analysis. All planned physiological measurements were successfully collected at the predefined time points (Day 1, Day 7, and Day 14). No participant withdrew from the study, and no adverse medical events were reported during the mission. The study was conducted across four separate isolation sessions, each lasting 14 days, with 10 participants per session. All sessions followed the same operational protocol, environmental conditions, and measurement procedures, allowing data to be pooled for descriptive analysis. Descriptive statistics of physiological parameters measured on Days 1, 7, and 14 of the isolated analog mission are presented in Table 1. Data are presented as median with interquartile range (IQR), mean ± standard deviation (SD), and distribution characteristics (skewness and kurtosis). All measurements remained within physiological reference ranges. Pairwise comparisons of physiological parameters measured on Days 1, 7, and 14 of the 14-day analog mission are presented in Table 2. P-values were obtained using paired comparisons with Holm correction. Due to non-normal distributions and limited temporal resolution, results are presented descriptively and do not imply causal inference.

TABLE 1. Descriptive statistics of physiological parameters measured during the 14-day isolation mission.

Descriptive statistics of physiological parameters measured on Days 1, 7, and 14 of the isolated analog mission. Data are presented as median with interquartile range (IQR), mean ± standard deviation (SD), and distribution characteristics (skewness and kurtosis). All measurements remained within physiological reference ranges.

TABLE 2. Pairwise comparisons of physiological parameters between mission days.

Pairwise comparisons of physiological parameters measured on Days 1, 7, and 14 of the 14-day analog mission. P-values were obtained using paired comparisons with Holm correction. Due to non-normal distributions and limited temporal resolution, results are presented descriptively and do not imply causal inference.

4.2 Body weight

Changes in body weight over the isolation period are summarized illustrate in Figure 3.

At the group level, mean body weight remained stable across the three measurement points. However, analysis of individual trajectories revealed noticeable inter-individual variability, with several participants exhibiting transient fluctuations of approximately ±1 kg during the mission (Figure 4).

The deviation from normality observed in the distribution supports the descriptive analytical approach applied in this study. Given the absence of body composition and hydration measurements, observed changes in body mass cannot be attributed to alterations in fat mass or lean tissue and are likely influenced by short-term fluid balance or daily variability.

4.3 Core body temperature

Mean core body temperature values remained within physiological reference ranges throughout the study period (Table 1). No systematic increase or decrease was observed across the three measurement points (Day 1, Day 7, and Day 14).

Individual temperature trajectories are presented in Figure 5, while the corresponding distributional characteristics are shown in Figure 6.

Although minor intra-individual fluctuations were observed, these variations remained within normal physiological limits and did not demonstrate a consistent temporal trend across participants. The observed variability likely reflects normal thermoregulatory responses influenced by daily activity patterns, environmental conditions, and individual physiological differences rather than pathological or adaptive changes related to isolation. The lowest recorded temperature value (31.6 °C) was observed in one female participant during the first measurement day. This participant had arrived shortly before the mission from Cyprus, and the transient decrease in measured temperature likely reflected short-term acclimatization to a markedly cooler indoor and outdoor environment rather than true core hypothermia. The value normalized on subsequent measurement days and was therefore interpreted as an individual, temporary physiological response to environmental transition.

4.4 Blood pressure

4.4.1 Systolic blood pressure

Systolic blood pressure values are summarized in Table 1 and illustrated in Figure 7. Mean SBP remained stable throughout the isolation period, with no consistent increase or decrease observed across the three measurement points.

Analysis of individual trajectories revealed moderate inter-individual variability; however, no consistent directional pattern was identified across participants.

The distribution of SBP values is presented in Figure 8, which demonstrates deviation from normality and supports the use of a descriptive analytical approach.

4.4.2 Diastolic blood pressure

Diastolic blood pressure values are presented in Table 1 and Figure 9. Similar to systolic pressure, DBP remained within physiological reference ranges throughout the study period. Individual variability was observed, but no systematic temporal trend was evident.

The corresponding distribution of DBP values is shown in Figure 10 (Q–Q plot).

The non-normal distribution further supports the descriptive interpretation of the data and precludes inferential statistical analysis.

4.5 Heart rate

Heart rate values across the study period are summarized in Table 1 and visualized in Figure 11. Mean heart rate remained within normal resting ranges at all time points. Although individual fluctuations were observed, no consistent increase or decrease was detected across the group.

Distribution analysis (Figure 12) demonstrated non-normality, supporting the use of descriptive statistics.

4.6 Peripheral oxygen saturation (SpO₂)

Peripheral oxygen saturation remained stable throughout the mission, with mean values consistently within normal physiological ranges (Table 1).

Individual trajectories are shown in Figure 13, and distribution characteristics are presented in Figure 14.

No episodes of clinically relevant desaturation were observed. Minor fluctuations were within expected physiological variability.

4.7 Summary of results

Across all analyzed physiological parameters:

• No statistically significant group-level changes were observed during the 14-day isolation period.
• All parameters remained within established physiological reference ranges.
• Inter-individual variability was present across all measured variables.
• Distribution analyses demonstrated non-normality for several parameters, supporting a descriptive analytical approach.
• No clinically relevant adverse trends were detected.

These results indicate that short-term isolation under controlled analog conditions is not associated with marked physiological alterations in healthy adults, although individual variability remains evident.

5 Discussion

The present study provides a descriptive evaluation of selected physiological parameters recorded during a 14-day isolated analog mission conducted under controlled terrestrial conditions. At the group level, body weight, core body temperature, blood pressure, heart rate, and peripheral oxygen saturation remained within physiological reference ranges throughout the observation period. No consistent temporal trends were observed, while inter-individual variability was evident across all parameters. These findings are consistent with previous reports from short-duration analog missions and confinement studies, which indicate that short-term isolation alone does not necessarily induce pronounced physiological alterations in healthy individuals (Foucher et al., 2021; Carrière et al., 2022; Snook and Mendell, 2004; NASA, 2020). Importantly, the present investigation was not designed to assess causal mechanisms or long-term physiological adaptation. Instead, it aimed to characterize short-term physiological stability and variability under isolated conditions, which represents an important but often underreported aspect of analog mission research.

5.1 Physiological stability and inter-individual variability

One of the most notable findings of this study was the presence of inter-individual variability in the absence of consistent group-level changes. This pattern has been repeatedly observed in analog and spaceflight-related studies and reflects the complex interaction between individual physiology, behavioral responses, and environmental exposure (Gangale, 2017; Riva et al., 2022; Gronwald BJ. et al., 2022; Perchonok and Bourland, 2002; Pagel and Chouktèr, 2016). Body weight remained generally stable across the observation period, with only minor fluctuations observed in individual participants. In the absence of body composition or hydration assessments, these changes cannot be attributed to alterations in fat or lean mass and are more likely related to short-term fluid balance or daily dietary variability, as reported in previous confinement and nutritional studies (Gronwald B. et al., 2022; Silva-Espinoza et al., 2020; Oeland et al., 2010; Reckelhoff, 2018; Jia et al., 2019; Hill et al., 2005). Core body temperature also remained within physiological limits. Minor fluctuations were observed, which are consistent with circadian variation and measurement-related variability. Similar findings have been reported in isolation and thermoregulation studies, where temperature stability is preserved in the absence of environmental extremes (Barnett et al., 2007; Kuht and Farmery, 2021; Uchida and Izumizaki, 2022; Chudecka et al., 2014).

5.2 Cardiovascular parameters and isolation

Systolic and diastolic blood pressure, as well as heart rate, showed no consistent temporal trends during the mission. These findings align with previous analog and clinical studies demonstrating that short-term confinement does not result in clinically significant cardiovascular changes in healthy individuals (Kuht and Farmery, 2021; Saeki et al., 2014; Hill et al., 2023; Christiansen et al., 2007). However, inter-individual variability was evident, which is consistent with the known sensitivity of cardiovascular parameters to circadian rhythm, physical activity, psychological stress, and autonomic regulation (Iqbal et al., 2023; Winterton et al., 2020; Holt-Lunstad et al., 2015; Tykarski et al., 2006; Verdecchia, 2000; Green et al., 2022; Zeijen et al., 2022). Moreover, prior studies have demonstrated that blood pressure variability and pulse pressure may be influenced by behavioral and emotional factors rather than isolation itself, particularly in short-duration studies (Green et al., 2022; Zeijen et al., 2022; Thibodeau et al., 2012; Berridge, 2008; Sung et al., 2020). The absence of continuous monitoring and standardized measurement timing in the present study likely contributed to the observed variability and represents an important methodological limitation.

5.3 Interpretation of distribution analyses

Distribution analyses revealed deviations from normality for several physiological parameters. Such findings are not unexpected in studies with limited sample sizes and a small number of repeated measurements. Similar distribution patterns have been reported in analog and spaceflight-related investigations, where biological variability and methodological constraints limit the applicability of parametric statistical approaches (Long et al., 2023; Richard et al., 2017; Hom et al., 2017; O’Riordan et al., 2023; Clopper and Pearson, 1934; Wallis, 2013). Accordingly, the present study relied primarily on descriptive statistics, and inferential testing was intentionally restricted. Distribution plots were included to enhance transparency and allow assessment of data structure rather than to support causal inference.

5.4 Methodological limitations

Several limitations of this study should be acknowledged. First, the relatively small sample size and incomplete datasets for some participants limit statistical power. Second, physiological measurements were obtained at only three time points, reducing temporal resolution. Third, body composition, hydration status, sleep quality, and physical activity were not objectively assessed, despite their known influence on physiological outcomes (Jia et al., 2019; Di et al., 2016; Bangash et al., 2022; Sondej and Zawadzka, 2022). Additionally, environmental parameters such as atmospheric composition and humidity were not continuously monitored, and measurement timing was not strictly standardized, which may have contributed to observed variability. These limitations are common in analog mission research and reflect the balance between experimental control and ecological validity (Clopper and Pearson, 1934; Wallis, 2013; Hill et al., 2005; Uchida and Izumizaki, 2022).

5.5 Context within long-term isolation research

When interpreted within the broader context of isolation research, the present findings align well with observations from long-term studies conducted in Antarctic research stations such as Concordia and Vostok. Comprehensive biomedical investigations at Concordia have demonstrated that pronounced physiological and neurobehavioral changes typically emerge only after prolonged exposure and are mediated by cumulative stress, circadian disruption, and environmental extremity rather than short-term confinement alone (Van Ombergen et al., 2021). Similarly, long-term observations at the Vostok station, considered an analog for future lunar and planetary habitats, have shown that meaningful physiological adaptation develops primarily during extended exposure to hypobaric hypoxia, isolation, and restricted mobility (Osetskiy et al., 2024). These findings underscore the distinction between short-term physiological variability and long-term adaptive processes.

5.6 Implications for future research

The present findings emphasize the need for more comprehensive monitoring strategies in future analog missions. The inclusion of continuous physiological measurements, standardized assessment protocols, body composition analysis, and psychological evaluations would significantly enhance data interpretability and comparability across studies (Morilak et al., 2005; Aston-Jones and Cohen, 2005; Vallejo-De la Hoz et al., 2023; Binsted et al., 2010). Moreover, extending mission duration and integrating detailed environmental monitoring would allow a more precise characterization of physiological adaptation processes relevant to long-duration exploration missions (Shiro et al., 2022; Heinicke et al., 2021; Agaptseva et al., 2024; Bednar et al., 2019; Klicker et al., 2023). Recent long-duration isolation studies, including Mars500 and SIRIUS missions, further highlight the importance of individualized cardiovascular and metabolic monitoring during extended confinement (Vigo et al., 2025; Elmoselhi et al., 2024; Parveen et al., 2026; Osetskiy et al., 2025).

5.7 Summary

In summary, this study demonstrates that a 14-day period of isolation in a terrestrial analog environment is not associated with clinically significant alterations in basic physiological parameters in healthy adults. While inter-individual variability was evident, no consistent trends indicative of physiological deterioration or adaptation were observed. These findings support the use of short-term analog missions as valuable platforms for studying physiological stability under isolated conditions, while underscoring the importance of extended-duration studies and comprehensive monitoring strategies to better understand long-term human adaptation to extreme environments.

6 Conclusion

This study provides a descriptive assessment of selected physiological parameters during a 14-day isolated analog mission. Body weight, core body temperature, blood pressure, heart rate, and peripheral oxygen saturation remained within physiological reference ranges, with no consistent temporal trends observed at the group level. Although inter-individual variability was present, no clinically relevant physiological alterations attributable to short-term isolation were identified. These findings suggest that short-term confinement alone does not substantially disrupt basic physiological homeostasis in healthy adults. The study’s descriptive design and limited temporal resolution should be considered when interpreting the results. Future investigations should include longer mission durations, standardized measurement protocols, and more comprehensive physiological and psychological monitoring to better characterize adaptive responses to prolonged isolation.

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Footnotes

Edited by: Antonio Mattia Grande, Polytechnic University of Milan, Italy

Reviewed by: Nikolay Osetskiy, Russian Academy of Sciences (RAS), Russia

Sagar Jagtap, Haribhai V. Desai College of Commerce, Arts and Science, India

Footnotes

LunAres, an analog space mission facility for scientific research; SpO₂, oxygen saturation; CVD, cardiovascular disease BP, blood pressure; SBP, systolic blood pressure; DBP, diastolic blood pressure; HR, heart rate; HRV, Heart rate variability; BMI, body mass index; ANS, autonomic nervous system.