Psychological stress denotes a condition of mental or emotional tension arising from unfavourable or challenging situations [1]. It occurs when individuals believe that the difficulties they encounter surpass their capacity to manage successfully. In contrast to physical stress, which pertains to urgent bodily risks, psychological stress is frequently related to emotional, social, or cognitive demands. It activates the body's stress response by stimulating the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system, resulting in physiological alterations including heightened heart rate, raised cortisol levels, and modified breathing patterns.

Hans Selye, the pioneer of stress study, defined stress as "the nonspecific response of the body to any demand for alteration." Psychological stress may be classified as acute (short-term) or chronic (long-term). Acute stress arises from certain events, such as examinations or public speaking, but chronic stress stems from persistent exposure to circumstances like financial hardships or tumultuous relationships. Stress may have both beneficial and detrimental effects. In limited amounts, it can improve performance and resilience; nevertheless, chronic or excessive stress can detrimentally affect physical and mental health, leading to issues such as anxiety, depression, cardiovascular illnesses, and respiratory dysfunction.

Psychological stress in young people is a considerable concern, impacting 15-20% of the worldwide population. Contributors to this stress encompass academic pressure, economic hardship, social media impact, and health and lifestyle elements [2]. Chronic stress can result in physical health complications, including cardiovascular disorders, gastrointestinal troubles, and compromised immune function, while mental health is adversely affected by elevated stress levels, resulting in anxiety, sadness, and exhaustion. Suicide rates are elevated among young adults, especially those enduring chronic stress. Addressing stress in young adults necessitates efficacious treatments, including stress education, mindfulness practices, counselling services, lifestyle modifications, and social support systems. Educational institutions and companies may provide programs to assist young adults in comprehending stress and cultivating coping strategies, while consistent exercise, nutritious meals, and sufficient sleep may markedly reduce stress levels.

The physiological effects of psychological stress are essential for comprehending its influence on breathing patterns [3]. The respiratory system, responsive to emotional and psychological conditions, frequently acts as an instant sign of stress. Alterations in breathing due to stress are not only symptoms; they also play a role in the body's whole stress response. Psychological stress stimulates the autonomic nervous system, namely the sympathetic division, which regulates the body's "fight or flight" response. This activation results in an elevated respiratory rate (tachypnoea) and superficial breathing (thoracic breathing) as the body endeavours to provide additional oxygen to satisfy perceived needs. Extended stress can disrupt normal respiratory function, leading to hyperventilation or persistent shallow breathing. Chronic stress-induced changes in breathing patterns can lead to long-term health complications, including cardiovascular disease, diminished immunological function, and heightened vulnerability to anxiety and depression.

Comprehending stress-induced respiratory alterations is essential for public health, particularly among high-stress demographics such as students and young professionals. Irregular breathing patterns frequently correlate with anxiety and panic episodes, underscoring the necessity of educating individuals and healthcare professionals on monitoring and regulating respiration. Public health specialists may create ways to instruct individuals on preserving optimal respiratory health, especially in high-stress scenarios [4]. Recognizing and mitigating stress-induced respiratory alterations in high-stress demographics can alleviate the overall strain on healthcare systems, diminish absenteeism in professional and educational settings, boost productivity, and improve overall quality of life. Establishing supportive settings that foster mental and physical well-being may mitigate the stigma associated with mental health, facilitate open discussions on stress, and advocate for policies that safeguard against its detrimental effects. Resilience training is a crucial element of stress management programs, aiding individuals in modulating their stress responses, safeguarding against the enduring consequences of chronic stress, and enhancing general well-being. Young adults frequently get insufficient focus in stress-related studies due to their susceptibility to significant life changes, such as scholastic constraints, job ambiguity, social and relational stress, and decisions regarding independence and life choices. This study work seeks to examine the impact of psychological stress on respiratory rate and breathing patterns in young people [5].

• Study Design:

This was a cross-sectional study designed to investigate the effects of psychological stress on respiratory rate and patterns in young adults. The study aimed to quantify changes in respiratory parameters under controlled stress-inducing conditions and analyse their association with perceived stress levels.

• Study Area:

The study was conducted in a controlled laboratory setting equipped with spirometry devices and wearable respiratory monitors to ensure standardized and accurate data collection. Participants were recruited from a university campus, ensuring easy access to a diverse group of young adults.

• Sample Size:

The study included 100 healthy young adults aged 18 to 25 years. The sample size was determined based on a pilot study and powered to detect significant changes in respiratory parameters between baseline and post-stress conditions.

• Sample Selection Criteria:

Participants were selected using the following criteria:

• Inclusion Criteria: Healthy individuals aged 18 to 25 years with no history of chronic respiratory, cardiovascular, or neurological disorders.
• Exclusion Criteria: Individuals with recent respiratory infections, ongoing medications affecting respiratory or stress responses, and diagnosed psychiatric conditions, including anxiety disorders.

• Procedure:

Upon entering the study, participants had to provide written informed consent, following which they received assurances about their participation and the study's objectives and procedures. Following the receipt of consent, we conducted an initial assessment to gather demographic information such as age, gender, and any pertinent medical history. This ensured that healthy individuals meeting the inclusion criteria only entered the study. Baseline measurements of respiration, including respiratory rate and patterns, were taken with spirometry and wearable respiratory monitors. The baselines provided reference readings for changes brought about by psychological stress. A standardized mental arithmetic task, to simulate psychological stress, was carried out. It involved making as many rapid calculations as possible in time and while being observed by researchers. Such a process was a controlled yet stressful environment. This was because the environment had been designed to induce responses from participants since it is one method applied to create cognitive pressure and performance anxiety. Immediately after the task is completed, the respiratory rate and patterns of the participants are measured again with the same instruments to capture changes caused by the stress stimulus. A validated scale, that is, the Perceived Stress Scale, was used in measuring the participants' levels of psychological stress. Scores obtained from the scales were then categorized into low, moderate, or high categories so that it would provide a basis for the analyses regarding how the participants' stress levels relate to changes in their respiration. In addition, the time that had elapsed for each respondent to recover back to their original respiration level after conducting the stress-evoking activity was recorded and taken as a recovery period. These periods of recovery were further included in the examination of physiological resilience against stress among respondents. The study also looked into gender differences in respiratory responses. A subgroup analysis was conducted to determine if the stress-induced changes in respiratory functions and recovery patterns are different in males and females. This analysis could help identify potential gender-specific responses to psychological stress and shed more light on the complex interplay between stress and respiratory function.

• Statistical Analysis:

All data were analysed using SPSS software. Baseline and post-stress respiratory parameters were compared using paired t-tests to identify significant changes. Correlation analysis was conducted to examine associations between PSS scores and respiratory parameters. Gender differences in respiratory responses were analysed using independent t-tests. Statistical significance was set at p < 0.05 for all tests. Descriptive statistics, including mean and standard deviation, were used to summarize demographic data and respiratory outcomes

Table 1 outlines the demographic characteristics of the 100 participants, evenly divided between males (n = 50) and females (n = 50). The average age of males was 21.5 ± 2.2 years, slightly higher than females at 21.1 ± 2.0 years. Males had a higher mean BMI (23.1 ± 3.6 kg/m²) compared to females (21.9 ± 3.1 kg/m²). The mean Perceived Stress Scale (PSS) score was lower for males (17.5 ± 5.8) than females (19.9 ± 6.4), indicating higher perceived stress levels among females. None of the participants had a smoking history or any reported chronic medical conditions, ensuring a healthy cohort for the study.

Table 2 highlights significant changes in respiratory parameters before and after the stress-inducing task. The mean respiratory rate increased from 16.8 ± 1.8 breaths/min at baseline to 20.1 ± 2.2 breaths/min post-stress, showing a 19.60% increase (p < 0.001). Tidal volume decreased by 6.20%, from 480.6 ± 32.4 mL to 450.8 ± 40.2 mL (p = 0.003). Minute ventilation rose by 12.30%, from 8.1 ± 0.8 L/min to 9.1 ± 1.1 L/min (p < 0.001). Additionally, irregular breathing patterns were observed in 31% of participants post-stress, a statistically significant finding (p < 0.001). These results indicate notable respiratory changes induced by psychological stress.

Table 3 presents the correlation between Perceived Stress Scale (PSS) scores and respiratory parameters. A strong positive correlation was observed between PSS scores and post-stress respiratory rate (r = 0.63, p < 0.001) as well as recovery time (r = 0.71, p < 0.001), indicating that higher stress levels were associated with increased respiratory rate and prolonged recovery. A moderate positive correlation was found with post-stress minute ventilation (r = 0.55, p = 0.002). Conversely, tidal volume showed a negative correlation with PSS scores (r = -0.45, p = 0.013), suggesting reduced tidal volume with higher perceived stress. These findings underscore the significant impact of stress on respiratory parameters.

Table 4 presents a gender-based comparison of respiratory responses. Males exhibited an average respiratory rate increase of 18.2 ± 4.1%, while females showed a slightly higher increase of 21.0 ± 3.8%, with the difference being statistically significant (p = 0.021). Recovery time was also longer for females, averaging 10.3 ± 2.4 minutes compared to 8.5 ± 2.1 minutes in males (p = 0.007). Additionally, a greater percentage of females (34%) exhibited irregular breathing patterns compared to males (28%), with this difference also being statistically significant (p = 0.045). These results suggest that females experience more pronounced respiratory changes and longer recovery times following psychological stress compared to males.

Table 5 shows the recovery time based on stress levels categorized by the Perceived Stress Scale (PSS). Participants in the low-stress category (n = 34) had a significantly shorter respiratory rate recovery time of 6.8 ± 1.5 minutes, compared to 9.2 ± 2.0 minutes in those with moderate stress (n = 38) and 11.6 ± 2.5 minutes in those with high stress (n = 28), with a p-value of <0.001. Similarly, the normalization time for breathing patterns was shorter in the low-stress group (7.2 ± 1.6 minutes) compared to the moderate (9.8 ± 2.1 minutes) and high-stress groups (12.2 ± 2.6 minutes), with a p-value of <0.001. These results indicate that higher perceived stress levels are associated with longer recovery times for both respiratory rate and breathing pattern normalization.

This demographic analysis shows that the sample was young adults with a mean age of 21.3 years and moderate levels of perceived stress as measured by the PSS scale with a mean score of 18.7 ± 6.2. Such results have been found in studies such as Cohen et al. (1983) [6], where the Perceived Stress Scale was validated and demonstrated comparable scores among university-aged subjects who experienced academic and social pressures. The absence of chronic diseases, as well as smoking history, ensured a homogenous sample; this is compatible with stress research by McEwen (2007) [7], which emphasized the control of confounding variables for studies on stress responses.

Important increase in the rate of breathing (+19.6%) and minute ventilation (+12.3%) that has been elicited by the stress-inducing task matches the findings provided by Lehrer et al. (2000) [8], which states acute psychological stress would cause hyperventilation as well as disrupting patterned breathing. The declining rate in the tidal volume of (-6.2%) resulted from the experimentation also aligns with studies conducted by Grassmann et al. (2016) [9], stating these respiratory effects regarding stress favor rate rather than depth, as a means to express "fight or flight" through physiological reactions.

A positive correlation was obtained between PSS scores and post-stress respiratory rate, r = 0.63, which is supported by Chrousos (2009) [10], who suggested that a higher perceived level of stress correlates with exaggerated responses of the respiratory system through enhanced sympathetic activation. Also, the scores of PSS were significantly correlated with recovery time in days (r = 0.71), which concurs with Thayer et al. (2012) [11], wherein stressed people took more time to recover, and this was surmised to be due to reduced parasympathetic tone.

There is a marked gender difference that comes up during this study, where females show more increased respiratory rate (+21.0%), and longer recovery times (10.3 ± 2.4 minutes). Similar trends have been reported by Becklake and Kauffmann, (1999) [12], who mentioned females respond more to the distress that could be due to hormone difference and higher stress experienced by them. Besides, "women have less effective recovery ventilation after stress" compared with men, as recent findings by Lehrer et al. (2004) [13] recently have stated; this subgroup analysis concurs with theirs.

Patients with higher PSS scores took significantly longer recovery times, (11.6 ± 2.5 minutes), as reported by studies by Romero et al. (2024) [14], which explained that the more stressed people are, the longer it takes to recover baseline physiological states because chronic stress induces some derangements in the balance of autonomic. This long recovery time further supports the theory of Viner (1999) [15] General Adaptation Syndrome, which explains that stress responses over time impede the body's ability to return to homeostasis.

The respiratory parameters of young individuals were significantly affected, exhibiting an increased respiratory rate, diminished tidal volumes, and altered breathing patterns compared to pre-stress values. Perceived stress levels and their correlations with changes in respiratory function, such as increased respiratory rate and prolonged recovery time. The study revealed that, on average, females exhibited somewhat larger elevations in stress-induced respiratory rate and prolonged recovery durations relative to males. These data suggest that physiological and stress reactions must be recognized and addressed, especially in high-stress environments like academia, and that treatments aimed at alleviating stress may mitigate its adverse effects on respiratory health. Future research may investigate the long-term consequences of chronic stress on respiratory function and perhaps develop tailored techniques for stress management to improve both mental and physical well-being.

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