Effects of a combined nature-based and audio-based virtual mindfulness intervention on stress and wellbeing of COVID-19 healthcare workers: a randomized controlled trial

Introduction

The COVID-19 pandemic has contributed to psychosocial distress experienced by healthcare workers. The context surrounding the care of patients with COVID-19 may involve witnessing patient death, death of colleagues, and the distress of exposing oneself and family to the virus (Huang et al., 2020; Murthy, 2022; Santarone, McKenney & Elkbuli, 2020). Healthcare workers (HCWs) working under these conditions can experience increased levels of stress, trauma, and psychosocial-spiritual distress (Andhavarapu et al., 2022; Cenat et al., 2021; Lee et al., 2023; Lu et al., 2020; Muehlhausen, 2021; Shanafelt, Ripp & Trockel, 2020; Wu et al., 2021). Such chronic stress and spiritual distress may culminate into burnout, which has been associated with impaired patient care and increased medical errors, posing risks to patient health (Fahrenkopf et al., 2008; Holland & Neimeyer, 2005; Jungmar Ridell & Orvelius, 2023; Muehlhausen, 2021; West et al., 2006).

Psychosocial-spiritual wellbeing is related to overall wellbeing and associated with improved coping ability and quality of life. Recent studies document the benefits of mindfulness and nature-based interventions for mental health and wellbeing, including their potential to mitigate the adverse effects of stress, depression, and anxiety (Coventry et al., 2021; Khoury et al., 2015; Labib, Lindley & Huck, 2020; Poulsen, Stigsdotter & Davidsen, 2018). Nature-based programs typically use outdoor activities such as rock climbing, surfing, and kayaking to promote wellbeing and personal growth (Herring, Knowles & Alschuler, 2021). These programs demonstrate efficacy in decreasing symptoms of depression, alienation, and improving self-efficacy (Rosenberg et al., 2014; Zebrack, Kwak & Sundstrom, 2017). Notably, however, benefits derived from nature-based programs can be short-lived and may require additional interventions to strengthen and prolong their efficacy (Kotera, Richardson & Sheffield, 2022).

Mindfulness interventions are evidence-based (Green & Kinchen, 2021; Melnyk et al., 2020; Yang et al., 2023) and represent a promising option in combination with nature programs to enhance benefit (Menardo et al., 2022). Mindfulness is defined as the awareness that emerges through paying attention, on purpose, in the present moment, and non-judgmentally to the unfolding of experience (Kabat-Zinn, 1990). Mindfulness-based interventions are highly correlated with psychosocial-spiritual wellbeing (Bagereka et al., 2023) and are reported to alleviate symptoms associated with stress and trauma (Lomas et al., 2019). Among HCWs, mindfulness-based interventions, including brief therapies, have been shown to reduce work-related stress, anxiety, and burnout while improving measures of wellbeing including job satisfaction, empathy, and fulfillment (Ameli et al., 2020; Chmielewski, Łoś & Łuczyński, 2021; Ghawadra et al., 2020; Goldhagen et al., 2015; Green & Kinchen, 2021; Krasner et al., 2009).

The present study proposes to combine a nature-based program with an audio-based mindfulness intervention to address stress and psychosocial-spiritual wellbeing. To investigate the efficacy of this combined intervention, we designed a study with three groups: the combined Nature-Mindfulness group (Combined), the Nature-only group (Nature), and a control group (Control). This design allows us to evaluate the specific and combined effects of nature-based activities and mindfulness practices on the wellbeing of healthcare workers. We hypothesize that HCWs in the Combined group will have greater reduction in stress and improvement in wellbeing when compared to the Nature and the Control groups. Similarly, we expect HCWs in either Nature group to have greater reduction in stress and improvement in wellbeing when compared to the Control group.

Materials & Methods

This randomized controlled study was approved by the National Institutes of Health (NIH) Institutional Review Board (IRB) at the Office of Human Subject Research Protection (OHSRP) approval number 000192 (NCT04846790). Verbal and written consent were obtained from each participant prior to enrollment. Data were collected anonymously and were deidentified, and study procedures were noninvasive. Participation was voluntary and all were informed that they could withdraw from the study at any time.

Study design and procedures

The study included three groups: a Combined Nature-Mindfulness group (Combined), a Nature-only group (Nature), and a control group (Control). The Combined group participated in both the nature program and the mindfulness program. The Nature group participated only in the nature program. The Control group did not participate in either program while completing the study assessments but later participated in the FD nature program.

Eligible participants were randomized into one of the three, Combined, Nature, or control groups. The randomization scheme was based on block sizes of six, with 2:2:2 random assignments into each group. Participants completed a demographic questionnaire. They also completed self-administered assessments at three or four time points, depending on group and per study design. REDCap automated prompts for tasks and assessments were emailed throughout the study. Each assessment took about 40 min to complete.

The Combined group completed a total of four assessments. Their baseline assessment (Assmt-0) was at least one week before starting the nature program. The day after the nature program had ended, participants completed another set of assessments, Assmt-1. They then began a 10-day audio mindfulness program, followed immediately by Assmt-2. The Combined group also completed a two-month follow-up assessment, Assmt-3. Throughout the eight weeks, participants received weekly reminders to engage in mindfulness activities that they had learned during the 10-day mindfulness program (see Fig. 1, study design).

The Nature group also completed a total of four assessments. Assmt-0 was at least one week before starting the nature program. The day after the nature program had ended, participants completed Assmt-1. Ten days later, they completed Assmt-2. A two-month follow-up assessment (Assmt-3) was also administered. Throughout the eight weeks, participants received short weekly surveys to monitor engagement (see Fig. 1).

Participants in the Control group completed three assessments: Assmt-0, Assmt-1, and Assmt-2. Assmt-1 was completed one week after Assmt-0, and Assmt-2 was completed ten days after Assmt-1 (Fig. 1). All assessments were administered before participation in the nature program. Assmt-2 (see Fig. 1) time point was the study primary endpoint for all participants. Follow up data were collected for the intervention (Combined or Nature) groups only. The 10-week follow-up assessment period was deemed an inappropriate wait time for Control group participants who were eager to participate in the FD nature. They were offered the mindfulness program on their own if they chose to use it following their study participation.

Results

Seventy-eight subjects were randomized to participate in the study. Fifty-three participants completed the study, including 16 in the Combined group, 19 in the Nature group, and 18 in the Control group. There was a comparable dropout rate for the two intervention groups with similar reasons for dropping out (see Fig. 2, the flow diagram).

The mean age was 35.7 ± 6.2 years. Participants indicated their gender as male (11%) or female (88%). Other gender identifications were not made. Participants were White (68%), Asian (21%), Black (2%), or Other (9%). The vast majority (70%) of participants worked in a hospital setting, and indicated their occupation as Nurse (55%), Physician (13%), Nurse Practitioner (7%), Physician Assistant (6%), or Social Worker (6%). All had exposure to COVID-19, either directly (77%), indirectly (4%), or both (19%). Participants reported their pandemic stress levels as no stress (0%), mild (0%), moderate (45%), severe (34%), very severe (13%), or extreme (7%). Further description of participant demographics is detailed in Table 1.

The mean baseline PSS score, the primary outcome measure, was 21.2 ± 3.2 in the Combined, 22.3 ± 2.8 in the Nature, and 23.2 ± 3.3 in the Control groups (Table 2). Following Assmt-2, the primary endpoint, PSS score was 20.3 ± 3.1 in the Combined, 20.9 ± 3.5 in the Nature, and 21.2 ± 2.8 in the Control groups. PSS at follow-up, the secondary endpoint, was 21.1  ± 2.1 in the Combined and 20.9 ± 4.9 in the Nature groups (Table 2). Notably, overall global tests of significance showed a p-value of 0.36 among the group and 0.045 across time, indicating no substantial change among the groups but suggesting some change over time (Fig. 3A).

The mean baseline NIH-HEALS score was 123.1 ± 19.4 in the Combined, 118.1 ± 17.1 in the Nature, and 114.3 ± 17.8 in the Control groups (Table 2). At the primary endpoint (Assmt 2), the mean NIH-HEALS score increased to 129.7 ± 19.7 in the Combined and 126.8 ± 21.3 in the Nature groups. The mean score in the Control group, at the primary endpoint, was 112.0 ± 15.3. At follow-up, the secondary time point for the intervention groups, the NIH-HEALS increased in the Combined group (131.3 ± 21.2) but decreased in the Nature group (120.4 ± 23.9) (Table 2). Overall global tests of significance showed a weak group effect (p = 0.044) and no time effect (p = 0.067) (Fig. 4A). However, aggregating data from the Combined and Nature groups into a single intervention arm yielded a substantial improvement in NIH-HEALS score when compared to the Control group (p = 0.019) (Fig. 4B).

Discussion

The present study reports the effects of a nature activity and a combined nature and mindfulness intervention on the stress and wellbeing of COVID-19 HCWs. The results demonstrated that engaging in nature-based and mindfulness-based activities did not significantly impact the stress levels as was hypothesized and assessed by the PSS, the primary outcome measure. The results, however, demonstrated that nature activity and nature combined with mindfulness can improve psychosocial-spiritual wellbeing as assessed by the NIH HEALs, a secondary outcome measure. The Combined group had greater improvement in wellbeing when compared to the Nature and the Control groups. Similarly, the Nature group had greater improvement in wellbeing compared to the Control group. Finally, at follow-up, the Combined group maintained improvements in wellbeing when compared to the Nature group. There were no notable changes in stress levels among the groups.

Mean PSS scores among our groups ranged from 21.2–23.2 at baseline and 20.9–21.1 at follow-up. These score ranges are consistent with moderate stress levels. PSS did not detect change neither between nor within the groups. Several factors might explain this result. The low statistical power of the study likely hindered our ability to detect change. Additionally, changes in PSS scores are typically small with 0.25−0.50 SD changes indicating meaningful effect. Given our small sample size, these small changes may have been particularly challenging to capture.

While a great deal of research report positive outcomes in mindfulness and nature exposure studies (Corazon et al., 2019; Green & Kinchen, 2021; Khoury et al., 2015; Van Den Berg & Custers, 2011; Van Dijk et al., 2017; Yang et al., 2023), the effectiveness of nature-based and mindfulness-based interventions on stress-related issues have also produced mixed results including or no improvements (Ghawadra et al., 2020; Goldhagen et al., 2015; Mygind et al., 2019; Tillmann et al., 2018). Differences in study design may account for these discrepancies. For instance, dose–response in both nature and mindfulness interventions are potentially quite important and such information are gradually emerging. Some studies cite that the most effective nature interventions typically span 8 to 12 weeks, with an optimal weekly dose of 20–90 min (Coventry et al., 2021). Similarly, standard mindfulness-based therapies often last 8 weeks, totaling in about 30-hours in MBSR^TR. The current interventions were briefer with 3–5 days of nature intervention, and a total of 3.5 h of mindfulness intervention. Although brief mindfulness interventions have been reported, they generally exceed four hours; for example, a 7.5-hour program effectively reduced stress in HCWs (Ameli et al., 2020). Interestingly, a study using mobile mindfulness applications for 10-minutes daily over 10 days significantly improved depressive symptoms and mindfulness (Flett et al., 2019).

In the present study, overall wellbeing was assessed using the NIH-HEALS, a measure of psychosocial-spiritual wellbeing. Results show that NIH-HEALS scores increased over time for both the Nature and the Combined groups. While these improvements were not statistically substantiated in between-group comparisons, aggregating the data from the intervention groups revealed a meaningful improvement in wellbeing relative to the control. Moreover, follow-up analyses showed that only the Combined group maintained its improvement two-months post-intervention. These findings indicate that nature programs improve wellbeing and that adding a mindfulness program may sustain the benefits overtime. As mentioned before, the study was not sufficiently powered to produce definitive results.

Our results are consistent with previous research showing that nature-based interventions improve overall wellbeing (Shanahan et al., 2016; Yang et al., 2023). These interventions, which include activities like therapeutic gardening and exposure to green spaces, have been shown to enhance mood, quality of life, and to increase overall emotional and psychological health (Annerstedt & Wahrborg, 2011; Petitt, Rolander & Johnsson, 2023; Van Den Berg & Custers, 2011). In the context of workplace wellbeing, incorporating nature activities could lead to better job and life satisfaction, and cognitive engagement in daily work activities (Gritzka et al., 2020).

Notably, however, the effects of nature-based interventions can be short-lasting (Kotera, Richardson & Sheffield, 2022). Our results indicate that mindfulness-based interventions can be combined with nature interventions to sustain positive psychosocial-spiritual wellbeing changes for at least two months. This is in line with previous research findings. Mindfulness interventions have been shown to promote psychosocial wellbeing and improve resilience in healthcare professionals (Lomas et al., 2019; Shiri, Nikunlaakso & Laitinen, 2023; Van Dijk et al., 2017). Recent evidence even suggests similar benefits from brief mindfulness programs as well as app-based digital interventions (Ameli et al., 2020; Taylor et al., 2022). Mindfulness interventions, including virtual guided meditations, such as mindful breathing exercises, and body scans, provide flexibility and accessibility. Short-term, audio, online, and virtual mindfulness interventions can be particularly viable methods to enhance wellbeing in HCWs with busy and or inflexible schedules.

There are several limitations to consider when interpreting the results. The study was underpowered and therefore the potential impact of the interventions was not fully captured. The small sample size and demographic profile of the participants, predominantly female, non-Hispanic white Christian nurses, may limit the generalizability of our findings to other groups and/or healthcare professionals. Nonetheless, the group adequately represents the healthcare workforce in the USA, with nurses being the predominant profession and women comprising over 87% of nursing workforce (U. S. Bureau of Labor Statistics, 2023). Our study spanned over two years, during which the profile and impact of COVID-19 evolved and changed. This could have influenced the participants stress levels as well as their motivation for participation in the study.

Finally, the drop-out rate in the intervention groups was high, at around 40%. While this is significant, attrition rates have been cited as high as 38% for face-to-face mindfulness interventions, with a mean of 19.1% (Lam, Kirvin-Quamme & Goldberg, 2022; Strauss et al., 2014). Attrition rates in nature-based interventions is not well documented, although a recent study reported a rate of 29% (Vermeesch et al., 2022). Among online mindfulness interventions, attrition rates can be seen as high as 59% (Nadler, Carswell & Minda, 2020). High attrition rates in online mindfulness interventions are largely attributed to the voluntary nature of participation and the lack of face-to-face instruction, which often leads to lower engagement compared to in-person programs.

In sum we did not detect change in stress levels, but nature and mindfulness interventions improved wellbeing. Future studies with larger sample size are needed to further elucidate the effectiveness of mindfulness interventions combined with nature activities, to improve and sustain the impact of nature related interventions.

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