The health impact of residential retreats: a systematic review

Lifestyle-related chronic diseases such as obesity, diabetes and lung disease are a global issue, which the World Health Organisation estimate account for 60% of all deaths [1]. These diseases are characterised by modifiable risk factors such as physical inactivity, unhealthy diet such as diets high in salt, sugar, fat, alcohol and tobacco, and exposure to environmental toxicants [1]. Unhealthy lifestyles are a major factor in the development of chronic disease and are directly addressed by the health retreat industry, which promises to deliver enhanced health and the reversal of chronic disease and age-related conditions by engaging people directly in healthy lifestyle behaviours and experiences [2‐4].

Health retreats have emerged from a history of travel to foreign destinations such as spas, hot springs, sacred sites, and pilgrimage locations that have been used as places of rest and rejuvenation for countless generations [3, 5]. Such locations have given rise to a booming wellness tourism industry that is estimated to have generated US$563.2 billion in revenues in 2015, with growth projections that are nearly 50% faster than for overall global tourism [6, 7]. A retreat may be defined as “a purpose-built centre which accommodates its guests for the purpose of learning/improving a body-mind activity (e.g., yoga, pilates) and/or learning-receiving complementary therapies or treatments whilst there” [2]. Retreats cover a broad spectrum of facilities ranging from low-cost ashrams in India [2, 3, 8] that focus on a spiritual-based lifestyle, to luxury lifestyle resorts [8], to residential centers that focus on chronic disease. Retreat guests range from people who want to improve their general health and learn positive lifestyle practices, to those facing life-threatening illnesses, and others who seek greater spiritual awareness or body-mind-spirit rejuvenation [9].

Despite the growing popularity of retreats and the growth of wellness tourism, the health impacts (either positive or negative) of attending retreats are uncertain and it is unclear if retreats offer any economic return for individuals or other stakeholders such as businesses, health insurance companies or governments. This paper aims to systematically review published studies that report on the health, wellbeing and economic impact of retreat experiences according to the PICOS approach (Participants, Intervention, Comparators, Outcomes and Study design) [10], and thereby explore the impact of these experiences on retreat guests.

There were 23 studies (reported in 28 articles) included in this systematic review, published over a 22-year period from 1995 to 2017 and involving 2592 participants. Of the 23 studies included, eight were randomised controlled trials (RCTs) including, one quasi-randomised trial and one randomised multi-centre trial; six non-randomised controlled trails and nine longitudinal cohort studies. A study flow chart is provided in Fig. 1. The results from the RCTs are presented in Table 1, results from the non-randomised controlled trials are presented in Table 2 and results from the longitudinal cohort studies are presented in Table 3.

The retreat industry is a niche sector of the wellness tourism industry that focuses on transformative experiences that aim to improve the health of participants through healthy lifestyle experiences, along with providing the skills and knowledge to help maintain healthy behaviours. The findings from the reviewed studies suggest there are many positive health benefits from retreat experiences that includes improvements in both subjective and objective measures. Most studies used a quasi-experimental design with small sample sizes, poorly described methodology with little follow-up data and reliance on self-report questionnaires to report on psychological and spiritual benefits. The results from the most rigorous studies that used randomized controlled designs were consistent with less rigorous studies and suggest that retreat experiences can produce benefits that include positive changes in metabolic and neurological pathways, loss of weight, blood pressure and abdominal girth, reduction in health symptoms and improvements in quality of life and subjective wellbeing.

In addition to facilitating general health improvements, there is evidence that retreat experiences can have a positive impact on chronic disease processes and provide benefits for some people with life threatening and/or chronic diseases. Of the four studies of retreat experiences aimed at improving quality of life for cancer patients [27, 28, 30, 36], all showed some benefits from retreat participation, including improvements in quality of life, depression and anxiety scores, and increased telomere length, with benefits being recorded up to five years post-retreat. Similarly, benefits of retreat participation are reported for people with multiple sclerosis with improvements in quality of life along with physical and mental health being evident up to five years post-retreat [31, 32]. Not all measures in the studies of life-threatening chronic diseases improved [30, 36], and as they are all small, poorly-controlled studies, more rigorous research is needed.

The finding that retreat experiences can lead to sustained and significant health improvements long after participants return home suggests that these experiences assist guests in making positive lifestyle changes and adopting healthy behaviours that lead to a variety of positive psychological, physiological, cognitive, clinical and metabolic effects. The ability to influence participants’ health once they return home is dependent on many factors including the type of participants involved, the education and experiences provided during the retreat program, and the provision of follow-up activities such as online coaching, nutrition programs, or follow-up consultations with practitioners. Of the four studies that showed a reduced effect over time in some measures [12, 17, 34, 35], two studies did not include a follow-up retreat component [12, 35].While it is not possible to determine which parts of the retreat intervention have the greatest influence, it is likely that improvements in health are due to a combination of psychological and behavioural factors that lead to better coping mechanisms and enhanced resilience to stress, as well as metabolic factors that lead to alterations in gene expression and DNA repair mechanisms that are evident in the observed changes in the metabolome [15] and teleomere length [27, 41].

Despite the potential for retreat experiences to benefit people with chronic and life threatening disease, the retreat industry does not routinely interact with the health care sector with few patients being referred to retreats by medical practitioners and retreat experiences generally not covered by third party payment schemes or eligible for tax deductions or incentives. The lack of integration between the healthcare and retreat sectors may be partly due to a lack of data with which to evaluate retreat experiences. Few retreats routinely collect and/or communicate data relevant to the healthcare sector, and even when formal studies such as those reviewed here are conducted, there is great heterogeneity in the range and scope of outcome measures, with few measures being comparable across studies. The retreat industry would therefore benefit from the use of a standardised dataset collected from guests on a routine basis. Such data could include a combination of psychological, cognitive, physiological, anthropometric and biochemical measures that together provide a holistic assessment of outcomes. This would allow retreat participants to evaluate and monitor the impact of their experiences and provide data to engage the medical profession and third party payers. It would also be beneficial for the industry to develop a standardised reporting system for retreat activities so that the influence of different types of retreat experiences can be assessed and results meaningfully compared across retreats and studies.

While retreat experiences appear to have positive health impacts, there is no published data on the economic impact of retreat experiences. There is however, substantial evidence that non-residential wellness programs, which share a similar focus on health promotion and lifestyle modification, provide a substantial economic return [42‐44]. A review of 28 studies of corporate wellness programs [45] finds that the economic benefit of participation is substantially higher than the costs of providing the program. Stead [45] reports benefit-to-cost ratios averaging 3.4–1 which indicates that corporate companies receive on average US$3.40 for every US$1 invested in the respective wellness program. In addition to return on investment, employees benefit from participating in corporate wellness programs through experiencing better health, lowered disability payments and reduced health care expenditures, while companies benefit from reduced employee turnover, increased productivity [45] and reduced absenteeism and presenteeism along with intangible benefits such as being an employer of choice and attracting highly skilled employees and creating a positive corporate culture [45, 46].

While the economic benefits of corporate wellness programs are becoming well established, it is unclear if similar benefits are offered by residential retreats. Future studies that include a health economic analysis are therefore needed to determine the cost-benefits of retreat experiences and the return on investment for participants, businesses, health insurers and policy makers. This may enable retreat operators to advocate for tax benefits, as well as inclusion in health insurance policies, and corporate wellness schemes. Furthermore, there is no data on the occurrence of adverse events. Future studies would benefit from including measures of adverse outcomes to confirm the safety and efficacy of retreat interventions.

Despite the consistent reporting of positive health effects from retreat interventions across multiple study designs and locations, the ability to draw definitive conclusions for any one condition or population is limited due to poor methodological rigor and substantial heterogeneity in study design, length and type of retreat program, target population, outcome measures and length of follow-up. Furthermore, while the reviewed studies included subjects from a wide range of demographic groups in multiple countries, only published English language studies were reviewed and it is uncertain if the findings can be generalized to the wider population. The use of mostly self-selected populations also introduces the possibility of selection bias, while a lack of blinding and adequate controls may introduce performance bias due to exposure to factors other than the specific intervention such as the vacation effect whereby health can improve from simply being removed from normal routines and behaviours. The lack of any reported adverse events may further indicate reporting bias with researchers not actively looking to identify adverse outcomes, or outcome measurement tools not being designed to capture adverse outcomes. Future studies, with more rigorous methodology and long-term follow-ups are now needed to determine the longevity of any effects, their mechanisms of action and the conditions most likely to respond.

The findings of this review suggest that retreat experiences appear to have positive health benefits that include benefits for people with chronic diseases. As the observed improvements in chronic diseases are based on a small number of patients, future research using larger numbers of subjects and longer follow-up periods is needed in order to determine the populations most likely to benefit and quantify any long-term health benefits. Future studies could also benefit from more rigorous study designs including the use of standardized outcome measures, more detailed descriptions of the retreat interventions and study population, and the inclusion of a health economics analysis in order to determine the economic benefits of retreat experiences for individuals, as well as for businesses, health insurers and policy makers.