Abstract Pets have been seen as good companions to human beings since the eons. The rapid growth in science and technology has made the working population more prone to stress and related disorders. This study aimed to assess the effects of pet rearing on stress and sleep among the working population in Chennai. This cross-sectional study included 210 working adult professionals with Indian government-approved pets (103) and without pets (107). The study population comprised 74 males and 136 females. The demographic details and pet activities of the participants were assessed using a general questionnaire. Subjective assessment of stress was performed using the Perceived Stress Scale and objectively using heart rate variability. Sleep Quality was assessed using the Epworth Sleepiness Scale. Both pet and non-pet owners were identical in demographic details and showed moderate stress, as assessed using the Perceived Stress Scale. Pet owners had reduced stress levels objectively (P <0.001), and sex-wise male pet owners had lower low-frequency and high-frequency heartbeat ratios (P <0.001), indicating lower stress than females. Pet owners were also found to have better quality of sleep than their counterparts (P = 0.006). The current study showed that pet rearing is associated with reduced stress and improved sleep quality among the working population in Chennai.

Keywords: Pet ownership, Stress, Sleep quality, Working professionals, Perceived stress scale, Epworth sleepiness scale

Citation: Arasu, P., Ramamoorthy, S., Subramanian, M., and Chandrasekar, M.D. 2025. Effects of pet ownership on stress and sleep quality among working professionals in Chennai: A cross-sectional study. Natural and Life Sciences Communications. 24(3): e2025044.

INTRODUCTION

Rapid growth in science and technology and the expansion of urbanization have resulted in enormous changes in human life. These technological changes have increased job opportunities, socio-economic status, and exposure to global networks, and have also significantly altered lifestyle patterns, including physical activity, sleep patterns and quality, food habits, and mental health, leading to lifestyle modifications among individuals. These lifestyle modifications have been shown to alter psycho-physiological functions, affecting overall health and well-being and making them more prone to a new set of disorders called lifestyle disorders (Hacker, 2024).     

Stress is defined as a non-specific response of the body to a stimulus, and its prevalence has been reported to increase worldwide. This is predominantly attributed to lifestyle modifications (McEwen, 2007). When an individual is subjected to stress, sympathetic nervous system is activated, resulting in release of stress hormones, such as catecholamines and cortisol, which trigger a surge in blood glucose levels and fatty acids, blood pressure, and mental alertness (Fink, 2016).

Sleep is an active physiological function required for both somatic and mental rejuvenation. WHO recommends 6-8 hours of night sleep for adults for a healthy life (Bull et al., 2020). Altered sleep patterns, reduced sleep duration, and poor sleep quality have also been demonstrated to activate the sympathetic nervous system, resulting in the release of stress hormones. Prolonged exposure to stress, poor sleep, and stress hormones has been shown to alter homeostasis, leading to the early development of metabolic disorders such as type II diabetes mellitus, hypertension, dyslipidemia, cardiac and renal diseases, infertility, and early death. Hence, managing stress levels and achieving good night sleep are required for good quality of life (Ramamoorthy et al., 2019).

Pets are legally authorized, domesticated animals that are reared at home by humans, and act as a source of guardianship, companionship, and support to humans. The relationship between humans and pet animals dates back centuries (Cucchi and Arbuckle, 2021). The earliest picture of a domesticated dog is seen in prehistoric paintings in Bhimbetka, India (Mathpal, 1998). Early literature has shown that a strong bond always exists between humans and pet animals (Smith, 2021). The Indian government allows certain animals (dogs, cats, fish, birds, and cattle) as pets and has also laid down laws for their protection and safety (D’Souza and Singh, 2020).

Research has demonstrated that companion animals play a significant role in human health and well-being. Pet dogs act as a source of affection and has been shown to alleviate loneliness, anxiety and stress (Wein, 2018). A study conducted in the United States showed that, in a stressful environment, the physical presence of a pet dog reduced stress levels among individuals (Foreman et al., 2017). Stroking a dog, cat, or any other pet has been shown to lower blood pressure and help an individual quickly feel calmer and less stressed (Applebaum et al., 2021).

Individuals who own pets are less likely to experience depression compared to those without pets. Furthermore, pet owners demonstrate reduced blood pressure in stressful situations relative to individuals who do not possess pets. Individuals who owned pets exhibited lower triglyceride and cholesterol levels compared to those without pets. Patients who possessed pets demonstrated increased longevity following myocardial infarction relative to those without pets. Pet owners aged 65 years and above made 30 percent fewer visits to their physicians than their counterparts without pets (Schreiner, 2016).

Companion animal ownership has been associated with improved physical and psychological outcomes, including reduced anxiety, decreased risk of cardiovascular disease, lower mortality rates, diminished loneliness, and enhanced emotional support during mental health crises (Brooks et al., 2018).

A study demonstrated that individuals who possessed aquariums and interacted frequently with their pet fish exhibited a greater reduction in induced anxiety levels. This reduction was comparable to that experienced by individuals who interacted with dogs or plants, suggesting that irrespective of species, companion animals contribute positively to human well-being. Even viewing human-pet animal interaction videos has been found to significantly reduce diastolic blood pressure (Clements et al., 2019).

Studies have shown that pets bring joy and happiness to an individual’s life. Various studies conducted among children, adolescents, college goers, and the elderly have shown that pet rearing has positive health benefits. However, the literature shows that there is a dearth of objective studies regarding the effect of pet rearing on stress and sleep among working professionals, although anecdotal experiences were shared. Working professionals face enormous work pressure, work targets, odd working hours, and responsibilities, leading to increased mental stress and poor sleep. Hence, the current study assessed the effects of pet rearing on stress and sleep quality among working professionals in Chennai.

MATERIAL AND METHODS

This cross-sectional study was conducted at Department of Mind Body Medicine & Lifestyle Sciences, Sri Ramachandra Institute of Higher Education & Research in compliance with the ethical guidelines for research involving human participants. The study protocol was approved by the Institutional Ethics Committee (approval number CSP/21/AUG/97/406 dated 02.09.2021) prior to the commencement of the study. Informed consent was obtained from all the willing participants.

Working adult professionals with Indian government-approved pets (n=103) and without pets (n=107) in Chennai were chosen as study participants (n=210). The study population comprised 74 males and 136 females. Participants below the age of 18 years, the non-working population, and those with known metabolic and neuropsychiatric disorders were excluded from the study.

General and health-related details were collected using a general health questionnaire, and pet-related data such as pet type, age, years of rearing, previous experience in handling pets, and involvement in pet-rearing activities were also collected.

Stress level was assessed subjectively using the Perceived Stress Scale (PSS) (Liu et al., 2020). PSS has ten questions with each question having five options. The total score was calculated and categorized as mild (0-13), moderate (14-26) and severe stress (27-40). Stress levels were objectively assessed based on Heart Rate Variability (HRV) using a validated HRV apparatus (Catai et al., 1996). HRV refers to the beat-to-beat change that occurs in an individual’s heart. HRV records time and the frequency domain parameter, Low-Frequency /High-Frequency heart beat ratio (LF/HF ratio), reflects the sympathetic-vagal balance in an individual, thus reflecting their stress level. As per the HRV task force, an LF/HF ratio above 2 indicates high sympathetic activity, indicating distress. The participants were instructed to have good night sleep, empty bladders, and avoid smoking and caffeine products before the HRV recording. They were asked to relax, and Lead II ECG was recorded using the HRV apparatus for five minutes (short-term recording). After recording, the data were analyzed using the Kubios software.

The Epworth Sleepiness Scale (ESS) was used to assess sleep quality in adults (Guo et al., 2020). It has eight questions inquiring about the chances of dozing in various situations. A total score < 10 was normal, and a score above that indicates excessive daytime sleepiness, an indicator of poor sleep hygiene.

Demographic variables and questionnaire data were documented and expressed as frequency and percentage. A chi-square test of independence was conducted to explore the association between pet ownership and scores on the Perceived Stress Scale and Epworth Sleepiness Scale. Quantitative data were expressed as Mean ± Standard Deviation (SD). Differences in HRV between professionals with and without pets and between males and females were analyzed using an independent t-test. SPSS Software version 18.0 was used for statistical analysis.

RESULTS

This cross-sectional observational study was conducted among adult working professionals in Chennai (n = 210). Of the 210 participants, 103 were pet owners and 107 were non-pet owners.

Baseline characteristics of the study participants

Table 1 presents the baseline characteristics of the study participants. The results highlighted that young adults (41.90%) between the ages of 18 and 25 years predominantly participated in the study. Similarly, the proportion of females (64.76%) was higher in this study.

Table 1. Baseline characteristics of the study population.

Note: The data are expressed as frequencies and percentages. N: Number

Pet animal details

This study revealed that most people preferred dogs as pets, with 89.32% of pet owners having dogs. Cats came second, owned by 6.79% of participants, while birds were the choice for only 0.97% (Table 2), which highlights a strong preference for canine companionship in the group studied. Interestingly, 40.77% of pet owners had pets for two years or less, suggesting that many participants had recently started keeping pets. On average, owners spent approximately 30 minutes a day with their pets, reflecting a moderate level of daily interaction. Additionally, 71.84% of pet owners actively participated in multiple pet-care activities such as walking, feeding, and grooming. This shows that most owners are more involved in their pets’ wellbeing.

Table 2. Pet animal details.

Note: The data are expressed as frequencies and percentages. N: Number; min: Minutes

Perceived stress among pet and non-pet owners

Table 3 shows the perceived stress levels of the study participants. The results showed that the majority of participants had a moderate level of stress (74.76%), followed by a severe level of stress (20.47%) and a mild level of stress (4.76%). Most pet owners had a moderate level of stress (61.20%), followed by severe stress (35.90%) and mild stress (2.90%). The majority of non-pet owners also had a moderate level of stress (87.90%), followed by a mild level (6.50%) and a severe level (5.60%).

Table 3. Perceived Stress Scale score among pet and non-pet owners.

Note: The data are expressed as frequencies and percentages. The chi-square test of independence was used to evaluate the relationship between pet ownership and perceived stress. N: Number; *: P<0.05.

Sleep quality among pet owners and non-pet owners

Most pet owners (44.66%) had lower normal daytime sleepiness, as measured by the ESS. In contrast, the majority of non-pet owners (42.10%) reported higher normal daytime sleepiness (Table 4). Pet owners had better sleep quality than their counterparts without pets (P = 0.006). Further, the data indicate that pet owners are less likely to suffer from mild, moderate, or severe excessive daytime sleepiness than non-pet owners.

Table 4. Epworth sleepiness scale score among pet and non-pet owners.

Note: The data are expressed as frequencies and percentages. The chi-square test of independence was used to evaluate the relationship between pet ownership and the Epworth Sleepiness Scale scores. N: Number; *: P <0.05.

HRV among pet owners and non-pet owners

HRV analysis revealed significant differences between pet and non-pet owners (Table 5). Pet owners exhibited higher parasympathetic nervous system (PNS) activity, as evidenced by increased mean RR interval (1,195.64 ± 197.17 ms vs 764.12 ± 141.36 ms, P <0.001), RMSSD (352.95 ± 73.13 ms vs 310.88 ± 35.92 ms, P <0.001), and PNS index (9.73 ± 1.86 vs 6.68 ± 2.47, P <0.001). Conversely, pet owners showed lower sympathetic nervous system (SNS) activity, with decreased mean heart rate (74.00 ± 18.67 bpm vs 80.80 ± 13.38 bpm, P <0.001), stress index (3.63 ± 1.28 vs 6.66 ± 1.20, P<0.001), and SNS index (-0.54 ± 0.20 vs 0.62 ± 0.19, P <0.001). Notably, the LF/HF ratio, an indicator of sympathovagal balance, was significantly lower in pet owners (1.67 ± 0.04 vs 2.26 ± 1.12, P <0.001), suggesting better autonomic balance. These findings indicate that pet ownership is associated with a more favorable HRV profile characterized by increased parasympathetic activity and decreased sympathetic activity, potentially reflecting lower stress levels among pet owners.

Table 5. Heart rate variability (HRV) among pet owners and non-pet owners across sexes.

Note: Data are expressed as Mean ± Standard deviation. Differences between the groups were analyzed using an independent t-test. n: number; RMSSD: Root mean square of successive RR interval differences; SD: Standard deviation; PNS: Parasympathetic Nervous System; HR: Heart rate; SNS: Sympathetic Nervous System; SDNN: Standard deviation of NN intervals; NN: Interbeat interval; pNN: Percentage of successive RR intervals that differ by more than 50 ms; RR: Interval between two R waves; TINN: Baseline width of the RR interval histogram; LF/HF: Low Frequency heart beats/High frequency heart beats; bpm: beats per minute; ms: millisecond; *: P<0.05.

Association of HRV with sex among pet owners

Heart rate variability (HRV) analysis revealed significant differences between male and female pet owners (Table 5). Male pet owners exhibited higher parasympathetic nervous system activity and lower sympathetic nervous system activity compared to female pet owners. Specifically, males had increased mean RR intervals (P <0.001), RMSSD (P =0.005), and PNS index values (P <0.001), along with decreased mean heart rate, stress index, and SNS index values (P <0.001). Most notably, male pet owners had a significantly lower LF/HF ratio (0.71 ± 0.20 vs 1.97 ± 0.91, P <0.001) compared to female pet owners, indicating better autonomic balance and potentially lower stress levels.

DISCUSSION

Pet rearing has been a social relationship imbibed by humans since its evolution. Pet association is a positive and symbiotic relationship between humans (O'Keefe et al., 2019). Recent lifestyle modifications have made humans more prone to stress and its associated disorders. Hence, this study was conducted to assess the effect of pet rearing on stress and sleep quality among working adult professionals in Chennai, India.

The study invited voluntary participation through various sources such as pet shops, a door-to-door approach, and social media. The majority of the study participants were within the age group of 18-25 years highlighting the fact that young urban working professionals prefer to have a pet that could counteract the stress they are exposed to or as a compensatory act for the increasing trend of nuclear families in society (Hall et al., 2017). Overall, the number of females was higher than that of males in the study, and even among pet owners, females were predominantly higher than males. In a study conducted on nurturing pets in Ireland, the number of female pet owners was higher than that of males (Downes et al., 2015). The female sex hormone estrogen is associated with stress and depression (Hokenson et al., 2021), and inhibits dopamine receptors in the brain. In addition, estrogen is associated with caring and bonding, which could explain the increased number of female pet owners in this study (Zhou et al., 2024).

Dogs were the preferred pet type among the pet owners in this study. A study conducted to assess subjective well-being among pet owners showed that dogs are the preferred choice of pet compared to other animals (Xin et al., 2021). The concept of pets in the human race started with dogs, and dogs are associated with loyalty, friendliness, and reliability. Dogs have a higher level of intelligence and are more easily trainable than any other pets. Hence, dogs are the preferred choice of pet owners (Bray et al., 2017).

The majority of pet owners in our study were within the age group of 18-25 years which is the beginning of their work/career, reflecting the fact that a higher percentage of pet owners were rearing pets between 0 and 2 years. A higher percentage of pet owners were found to spend 30-60 minutes/day with their pets and were also found to be involved in multiple rearing activities such as walking, feeding, and grooming. Spending time with pets is a major factor that has an impact on pet owners. This allowed us to study the effects of pet rearing on stress and other physiological parameters.

Stress was assessed using both subjective and objective parameters. Subjective measurements of stress were assessed using the PSS and objectively using HRV. Assessment of stress using the PSS showed that both groups had a moderate level of stress, which predominantly indicated the perceived stress status among the working population in recent days (Ezekekwu et al., 2025). Among the study groups, pet owners were found to experience less moderate stress than non-pet owners. Following moderate stress, pet owners were found to have severe stress followed by mild stress, whereas it was the opposite among non-pet owners. Recently, pet rearing, more than a committed and enjoyable process, has been considered a serious and attention-seeking process. Young adults, due to increasing nuclear family trends, social media, and peer pressure, were seen to indulge in exhaustive pet-rearing processes, such as professional pet grooming, makeover, and photoshoots, buying costly toys and dresses for their pets (McDonald et al., 2022), resulting in the development of severe perceived stress. In addition, leaving pets at shelters during travel and illness of the pets could have been the other factors for increased severe perceived stress next to moderate stress among pet owners.

Objective assessment of stress was performed by HRV measurement, which is a reflection of sympathovagal balance. HRV assessment performed using the Parasympathetic Nervous System (PNS), Sympathetic Nervous System (SNS), and Time and Frequency domain components showed that pet owners had significantly increased PNS parameters such as mean interval between two R waves (mean RR), root mean square of successive RR interval differences (RMSSD), and PNS index, and reduced SNS parameters such as mean heart rate (HR), stress index, standard deviation 2% (SD2%), and SNS index. Time domain parameters, such as the percentage of successive RR intervals that differ by more than 50 ms (pNN50), which reflect HF and Baseline width of the RR interval histogram (TINN), which reflects total power, were found to be increased among pet owners. The frequency domain parameter LF/HF ratio, which is an indicator of sympatho-vagal balance (sympathetic-parasympathetic activity), was found to be better among pet owners, showing that pet ownership objectively provides a marked reduction in autonomic activity and stress levels among individuals (Yilmaz et al., 2018).

Based on sex, HRV assessment showed that there was an increase in PNS parameters, such as Mean RR, RMSSD, SD1% and PNS index among males. A decrease in SNS parameters, such as SD2% and the SNS index, was also observed among males. Males were found to have increased NN50, pNN50, RR index, and TINN (indicators of HF and Total power) in the time-domain parameters and a marked reduction in the LF/HF ratio in the frequency-domain parameter. The LF/HF ratio is a power spectral frequency component of HRV that reflects sympathovagal balance in an individual. An LF/HF ratio between 1.5-2.0 is considered normal (Yilmaz et al., 2018), and in the current study, male pet owners had a significant reduction in the LF/HF ratio, indicating reduced stress among male pet owners. The male sex hormone testosterone is associated with being social, dominant, and responsible (Bredewold and Veenema, 2018), and Indian sociocultural factors favour males to spend more time with pets at home than females, which could have contributed to reduced stress among male pet owners than among females. HRV studies have been performed under various conditions and diseases (Shaffer and Ginsberg, 2017). In the current study, the effect of pet rearing on stress was studied using subjective (PSS) and objective tools (HRV), and it was shown that pet rearing is associated with decreased stress levels, especially among male pet owners.

Sleep is a physiological process required for psychosocial well-being. Good night sleep has been associated with physical and mental rejuvenation. Good night sleep is associated with increased work efficiency and productivity, better interpersonal relationships, and better social wellbeing. Recent lifestyle changes have altered sleep patterns among individuals, leading to early development of lifestyle disorders (Ramamoorthy et al., 2014). In the current study, sleep hygiene was assessed using ESS, and it has been shown that pet owners have a better quality of sleep than their counterparts. In one study, pet rearing was found to have a positive association with sleep hygiene, which was assessed using the Pittsburgh Sleep Quality Index (Rosano et al., 2021). Pet-rearing is associated with bonding, hugging, and love. These behaviours decrease the sympathetic surge and cortisol levels and increase the release of serotonin, oxytocin, and pleasure hormones (Oliva et al., 2019). Increased levels of stress hormones are associated with chronic inflammation, increased free radical levels, and sleep disturbances that may lead to the disruption of blood brain barrier (Paithoon et al., 2025). Pet-rearing activities and behaviour increase the level of pleasure hormones in the body, which in turn improves psychosomatic health, contributing to reduced stress levels and improved quality and quantity of sleep.

Studies have reported mixed results regarding the impact of pets on sleep quality. Some research suggests that pet owners, particularly those who share their bedrooms with pets, may experience more sleep disturbances and lower sleep efficiency than non-pet owners (Chin et al., 2024). Factors such as pet movement, noise, and the need for nighttime care can contribute to fragmented sleep. However, other studies have found that the presence of pets can provide comfort and security, potentially leading to improved sleep quality in some individuals (Hoffman et al., 2018). The relationship between pet ownership and sleep quality appears to be complex and is influenced by factors such as pet type, sleeping arrangements, and individual preferences.

The findings of the current study show that pet rearing decreases stress and improves sleep quality among working professionals, and could be considered a part of broader stress management and wellness programs for them. These results can be further enhanced by conducting longitudinal randomized controlled trials to establish a causal relationship between pet ownership, improved stress, and sleep outcomes. Diverse populations by age, socioeconomic status, geographic location, and culture could be included, which would help in generalizing the findings. The physiological and psychological mechanisms through which pet ownership may reduce stress and improve sleep quality can be investigated.

LIMITATIONS

The study population was limited to working professionals in Chennai, which may not represent a broader population, including those in different professions, geographic locations, or cultural contexts. Being a cross-sectional study, it can only suggest associations, rather than causal relationships, between pet rearing and stress or sleep quality. ESS involves self-reported measures that can introduce subjectivity and potential bias into the findings. The study predominantly involved dog owners, with limited representation of other pets, reducing the variety and reporting fewer human-pet interactions. Although the study tried to contain variations in the demographic variables, other confounding factors, such as the participants' overall health, lifestyle, and social support systems, may influence stress and sleep quality.

CONCLUSION

The current study, conducted among working adult professionals in Chennai, showed that young working professionals, especially females (64%), preferred pets, and dogs (89%) were the most preferred pet animals. Most pet owners had significantly lower moderate levels of stress (61.2%), higher PNS index (9.73 ± 1.86), and lower SNS index (-0.54 ± 0.20) than non-pet owners. Male pet owners were found to have a significant sympathovagal balance in HRV (LF/HF ratio 0.71, P <0.001), indicating that male pet owners had reduced stress levels. Sleep quality assessed using ESS showed significantly reduced daytime sleepiness (44.7% with a score of 0 – 5, P =0.006), indicating better sleep quality among pet owners. Despite the inability to establish a causal relationship using this cross-sectional design, the current study shows that pet rearing objectively decreases stress and improves sleep quality among working professionals in Chennai. These findings suggest that pet rearing could be considered part of broader stress management and wellness programs for working professionals. Future studies with a longitudinal design and more diverse samples across different geographic locations could establish the causality and universality of these findings. Interdisciplinary research involving physiology, psychology, and occupational health could unravel pet-rearing interactions with stress management and sleep improvements.

ACKNOWLEDGEMENTS

The authors express their gratitude to Dr. G. Pitchaimani, Assistant Professor of Medical Sociology, Faculty of Allied Health Sciences, Sri Ramachandra Institute of Higher Education & Research, for his assistance with the statistical analysis.

AUTHOR CONTRIBUTIONS

Srihari Ramamoorthy designed and supervised the study. Priyadharshini Arasu conducted the study. Manickam Subramanian and Mathangi Damal Chandrasekar wrote the manuscript. All authors have read and approved the final manuscript.

CONFLICT OF INTEREST

The authors declare that they have no competing interests.

ETHICAL STATEMENT

This study was conducted in accordance with ethical principles of research involving human participants. The study protocol was approved by the Institutional Ethics Committee of Sri Ramachandra Institute of Higher Education and Research, Chennai (approval number CSP/21/AUG/97/406 dated 02.09.2021) prior to the commencement of the study. All participants provided informed consent before taking part in the study.

REFERENCES

Applebaum, J.W., Ellison, C., Struckmeyer, L., Zsembik, B.A., and McDonald, S.E. 2021. The impact of pets on everyday life for older adults during the covid-19 pandemic. Frontiers in Public Health. 9: 652610.

Bray, E.E., Sammel, M.D., Cheney, D.L., Serpell, J.A., and Seyfarth, R.M. 2017. Effects of maternal investment, temperament, and cognition on guide dog success. Proceedings of the National Academy of Sciences.  114(34): 9128-9133.

Bredewold, R., and Veenema, A.H. 2018. Sex differences in the regulation of social and anxiety-related behaviors: Insights from vasopressin and oxytocin brain systems. Current Opinion in Neurobiology.  49: 132-140.

Brooks, H.L., Rushton, K., Lovell, K., Bee, P., Walker, L., Grant, L., and Rogers, A. 2018. The power of support from companion animals for people living with mental health problems: A systematic review and narrative synthesis of the evidence. BMC Psychiatry.  18: 31.

Bull, F.C., Al-Ansari, S.S., Biddle, S., Borodulin, K., Buman, M.P., Cardon, G., Carty, C., Chaput, J-P., Chastin, S., Chou, R. et al. 2020. World health organization 2020 guidelines on physical activity and sedentary behaviour. British Journal of Sports Medicine. 54(24): 1451-1462.

Chin, B.N., Singh, T., and Carothers, A.S. 2024. Co-sleeping with pets, stress, and sleep in a nationally-representative sample of United states adults. Scientific Reports.  14: 5577.

Clements, H., Valentin, S., Jenkins, N., Rankin, J., Baker, J.S., Gee, N., Snellgrove, D., and Sloman, K. 2019. The effects of interacting with fish in aquariums on human health and well-being: A systematic review. PLoS One.  14(7): e0220524.

Cucchi, T., and Arbuckle, B. 2021. Animal domestication: From distant past to current development and issues. Animal Frontiers. 19; 11(3): 6–9.

Downes, M.J., Devitt, C., Downes, M.T., and More, S.J. 2015. Neutering of cats and dogs in Ireland; pet owner self-reported perceptions of enabling and disabling factors in the decision to neuter. PeerJ.  3: e1196.

D’Souza, L., and Singh, R. 2020. Legality of the use of animals for recreational purposes in India [Internet]. National Law School of India University; Aug 2020 [accessed 2025 Apr 15]. https://ceerapub.nls.ac.in/legality-of-the-use-of-animals-for-recreational-purposes-in-india/.

Ezekekwu, E., Johnson, C., Karimi, S., Lorenz, D., and Antimisiaris, D. 2025. A longitudinal analysis of long working hours and the onset of psychological distress. Journal of Occupational and Environmental Medicine. 67(1): 11-18.

Fink, G. 2016. Stress, definitions, mechanisms, and effects outlined: Lessons from anxiety. Vol. 1 p 3-12. In: Fink G, editor. Stress: Concepts, cognition, emotion, and behavior. Academic Press.

Foreman, A.M., Glenn, M.K., Meade, B.J., and Wirth, O. 2017. Dogs in the workplace: A review of the benefits and potential challenges. International Journal of Environmental Research and Public Health.  14(5): 498.

Guo, Q., Song, W.D., Li, W., Zeng, C., Li, Y.H., Mo, J.M., Lü, Z.D., and Jiang, M. 2020. Weighted Epworth sleepiness scale predicted the apnea-hypopnea index better. Respiratory Research.  21: 147.

Hacker, K. 2024. The burden of chronic disease. Mayo Clinic Proceedings: Innovations, Quality and Outcomes. 8(1): 112-119. 

Hall, S.S., Wright, H.F., and Mills, D.S. 2017. Parent perceptions of the quality of life of pet dogs living with neuro-typically developing and neuro-atypically developing children: An exploratory study. PLoS One.  12(9): e0185300.

Hoffman, C.L., Stutz, K., Vasilopoulos, T. 2018. An examination of adult women’s sleep quality and sleep routines in relation to pet ownership and bedsharing. Anthrozoös.  31(6): 711-725.

Hokenson, R.E., Short, A.K., Chen, Y., Pham, A.L., Adams, E.T., Bolton, J.L., Swarup, V., Gall, C.M., and Baram, T.Z. 2021. Unexpected role of physiological estrogen in acute stress-induced memory deficits. The Journal of Neuroscience.  41(4): 648-662.

Liu, X., Zhao, Y., Li, J., Dai, J., Wang, X., and Wang, S. 2020. Factor structure of the 10-item perceived stress scale and measurement invariance across genders among chinese adolescents. Frontiers in Psychology.  11: 537.

Mathpal, Y. 1998. Rock paintings of Bhonrawali Hill in central India: Documentation and study. Purakala. 9(1-2): 5-52.

McDonald, S.E., Doherty, C., Sweeney, J., Kisiel, L., Matijczak, A., Niestat, L., and Gupta, M. 2022. Barriers to and facilitators of pet grooming among clients served by a subsidized grooming service program. Frontiers in Veterinary Science.  9: 1021707.

McEwen, B.S. 2007. Physiology and neurobiology of stress and adaptation: Central role of the brain. Physiological Reviews.  87(3): 873-904.

O'Keefe, J.H., O'Keefe, E.L., and Lavie, C.J. 2019. The human-canine bond: A heart's best friend. Mayo Clinic Proceedings: Innovations, Quality and Outcomes. 3(3): 249-250.

Oliva, J.L., Mengoli, M., Mendonça, T., Cozzi, A., Pageat, P., Chabaud, C., Teruel, E., Lafont-Lecuelle, C., and Bienboire-Frosini, C. 2019. Working smarter not harder: Oxytocin increases domestic dogs' (Canis familiaris) accuracy, but not attempts, on an object choice task. Frontiers in Psychology.  10: 2141.

Paithoon, R., Sriyakul, K., Tungsukruthai, P., Srikaew, N., Sawangwong, P., Tungsukruthai, S., and Phetkate, P. 2025. Effectiveness of herbal steam bath therapy for quality of life and sleep quality in post-covid-19 patients. Natural and Life Sciences Communications.  24(1): e2025009.

Ramamoorthy, S., Damal Chandrasekar, M., and Ramnath, S. 2014. Osa: An awaking disorder! IOSR Journal of Pharmacy.  4(4): 04-07.

Ramamoorthy, S., Kamaldeen, D., Ravichandran, L., and Sundaramahalingam, M. 2019. Effect of stress on sleep hygiene among school going adolescents in Chennai. Journal of Family Medicine and Primary Care.  8(9): 2917-2920.

Rosano, J., Howell, T., Conduit, R., and Bennett, P. 2021. Co-sleeping between adolescents and their pets may not impact sleep quality. Clocks and Sleep.  3(1): 1-11.

Schreiner, P.J. 2016. Emerging cardiovascular risk research: impact of pets on cardiovascular risk prevention. Current Cardiovascular Risk Reports. 10(2): 8.

Shaffer, F., and Ginsberg, J.P. 2017. An overview of heart rate variability metrics and norms. Frontiers in Public Health.  5: 258.

Smith, T.D., and Van Valkenburgh, B. 2021. The dog-human connection. Anatomical Record. 304(1): 10-18.

Wein, H. 2018. The power of pets health benefits of human-animal interactions. NIH News in Health. 2: 1-2. https://newsinhealth.nih.gov/sites/newsinhealth/files/2018/February/ NIHNiHFeb2018.pdf

Xin, X., Cheng, L., Li, S., Feng, L., Xin, Y., and Wang, S. 2021. Improvement to the subjective well-being of pet ownership may have positive psychological influence during covid-19 epidemic. Animal Science Journal.  92: e13624.

Yilmaz, M., Kayancicek, H., and Cekici, Y. 2018. Heart rate variability: Highlights from hidden signals. Journal of Integrative Cardiology. 4(5): 1-8.

Zhou, H., Zhu, R., Xia, Y., Zhang, X., Wang, Z., Lorimer, G.H., Ghiladi, R.A., Bayram, H., and Wang, J. 2024. Neuropeptides affecting social behavior in mammals: Oxytocin. Peptides. 177: 171223.

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