Without vaccines and effective treatments, public health approaches to controlling the COVID-19 pandemic will continue to depend on measures such as isolation, quarantine, physical distancing, and increased hand-washing. Some of these measures, such as physical distancing and quarantine, may negatively impact mental health when implemented simultaneously and for long periods of time [1]. This in turn can influence adherence to the public health measures [2], potentially undermining their effectiveness over time.

Evidence-based strategies are urgently needed to mitigate the short- and long-term impact that some public health measures might have on mental health. As access to in-person health resources may be limited during the COVID-19 public health emergency, alternative and complementary activities that promote mental health and wellbeing need to be explored and identified. Of particular importance are activities that can be performed at home and that do not require facilitation by mental health professionals. These activities include those that can be performed by an individual or in groups as facilitated by video conferencing platforms.

Currently, there is extensive literature on the impact of various activities on mental health in general. To our knowledge, there has been no study that has examined activities that can promote mental wellness during pandemics, quarantines, social isolation or other stress-inducing events. This study was conducted to help address that gap in knowledge.

This rapid review study was informed by the guidelines provided by the Cochrane Collaboration [3].

Our search identified a total of 1,781 records obtained from databases and from backward and forward searches. After removing all duplicates, we screened 1,236 unique titles and abstracts and excluded 1,076. Of the 160 articles that were reviewed in full, 16 met all study criteria and 144 were excluded. The reasons for excluding the articles and the review process are summarized in Fig 1.

The 16 included studies, half of which were RCTs, investigated the effects of five types of activities on various mental health outcomes. The most frequently investigated activities were exercise (eight studies) and yoga (five studies). The mental health outcomes examined pertain to reduction in anxiety, depression, psychological distress, feelings of hopelessness, and improvement in overall symptom severity.

Of the 16 included studies, 13 were conducted in prisons; the other 3 were conducted in a forensic psychiatry unit, hospital ward, and community setting. All of the exercise studies were conducted in group settings with no indications that the activity could not be performed alone. Likewise, in the yoga studies, which were all done in classes led by a yoga instructor, the activity was described as an activity that could be performed alone. Only one study, an RCT investigating the effect of progressive muscle relaxation technique on anxiety in a sample of hospitalized individuals, was conducted during the COVID-19 pandemic.

A summary of the characteristics of each included study and details on the reported outcomes are presented on Table 1.

This rapid review found evidence indicative of the potential role of exercise, yoga, and other activities like progressive muscles relaxation, listening to music, and religious activities on mental wellness. The eligible studies have reported mostly favourable changes or differences associated with these activities on various mental health outcomes including anxiety, depression, and psychological distress. In one study, however, a counter intuitive effect was reported suggesting a specific type of religious activity, namely solitary religious activity, is associated with higher PTSD symptoms. Overall, the methodological limitations in the eligible studies characterize the body of evidence as being at risk of bias and preclude precise estimation of the magnitude of the impact.

We posit that the risk of bias in the evidence is largely due to the use of self-report measures of mental health outcomes, participants’ partial awareness of the study purpose, outcome, and the activities they are performing, and the relatively short interval between the onset of the intervention and outcome measurement. These limitations are common in mental health research and are most of the time challenging to overcome. For example, it is often not feasible to blind participants to the study conditions if the intervention involves exercise, yoga, or relaxation. As well, participants’ adherence to or persistence in pursuing an activity is likely associated with their perception that the activity has resulted in a change in their mental well-being. Nevertheless, the use of self-reported outcomes in mental health research is acceptable if the tools have good psychometric properties for the target population, even though it can be expected that the data remains susceptible to self-reporting bias [27].

The generalizability of the evidence is high as the studies were conducted in various countries, populations, and contexts, including in very low resource settings that have a number of commonalities with what most people will experience during public health restrictions or lockdown. The findings are particularly useful and relevant to the COVID-19 pandemic because many of the activities identified can be done at home, and without the assistance of a mental health professional or trained clinician. This is important for systems with shortages of mental health professionals and for vulnerable populations who do not have access to the healthcare system due to stigma and other inequities.

It should be noted that our search did not yield studies that investigated exercise or yoga in purely individual settings. Because of this, the effect sizes reported in these studies may differ from what could be achieved if these activities were performed alone. With exercise, some studies suggest that synergistic effects can be observed if exercises are performed in group settings [28]. On the other hand, there appears to be no evidence of difference in the self-reported benefits that can be derived from performing yoga alone versus in a group setting [29].

Various pathways have been proposed to explain how the activities identified in this review might contribute to mental wellness. Most explanations postulate that effects on mental well-being are mediated through changes in physiology, brain chemistry, affect, behavior, and in perceived social support. A brief summary of the proposed pathways for each activity is presented in the next paragraphs.

Exercise. Exercise’s impact on mental health has mostly been attributed to its physiological and psychological affects. The anxiolytic and antidepressant properties of exercise, for example, appear to be mediated by its effects on body temperature [30], brain opioid systems [31], adrenal activity, and noradrenaline and dopamine, which play an important role in stress adaptation and mood regulation [32]. Exercise also acts as a form of distraction from stressful situations, thereby creating a sense of control, which improves overall mental wellbeing [32]. Lastly, exercise can produce short-term psychological effects such as increased feelings of vigour and self-esteem, and reduce anxiety, fatigue, and tension [33, 34].

Relaxation. Progressive relaxation has been shown to decrease anxiety and stress by reducing the activity of the sympathetic nervous system, which in turn increases mental relaxation [35]. The two-step process of contracting and releasing muscles activates a relaxation response, which improves the body’s overall functioning and decreases stress levels [36].

Yoga. The practice of yoga involves the body, breath and mind, affecting many systems simultaneously and resulting in reduced anxiety and perceived stress [37] and increased positive well-being [38]. The impact of yoga on mental well being, has been suggested to be mediated mainly by improvement in autonomic responses to stress and coping behaviours [39]. Some studies also suggest that yoga practice is linked to improved immunity and stress regulation [40] as well as better emotional regulation [41].

Music. Several studies highlight that listening to relaxing music reduces agitation, anxiety, anger, negative thoughts, and aggression among various populations [42]. Relaxing music is generally characterized as music with steady, slow, repetitive and flowing rhythms that are similar to a relaxed heart rate [43]. Relaxing music’s effect has been attributed to its ability to decrease sympathetic nervous system activity, state anxiety, and stress [44, 45]. Additionally, relaxing music can act as a distractor from negative stimuli, allowing listeners to focus on pleasant thoughts, which reduces stress, anxiety, and negative mood [46].

Religious activities. Religion and spirituality have been associated with physical and mental health including responses to stress, anxiety and depression [47–50]. Religiosity involves personal and social factors that can contribute to health and wellbeing, such as perceived social support from the religious community [50]. Perceived social support itself has been shown to correlate with reduced psychological distress, and reduced post-traumatic stress disorder [51]. Some aspects of religiosity, however, have been reported to be negatively associated with mental wellness. For example, religiosity associated with religious struggles have been found to be associated with more depression [52]. As well, some forms of religiosity that are practiced independently of a church or religious organization have been linked to higher PTSD symptoms [26, 53].

There is some evidence that activities that can be performed at home can promote mental wellness. Physical activity such as exercise and yoga can be helpful across a broad range of symptoms of mental illness. Due to limitations in the study designs that form the evidence-base for these activities, we recommend that these activities be promoted or offered in conjunction with conventional mental health services when directed towards persons with pre-existing mental health conditions. Also, combining the activities identified in this review with standard therapies delivered online may produce better results, particularly for people experiencing moderate to severe symptoms.

Guidelines on home-based activities that have the potential to promote mental wellness are needed. These will help minimize potential adverse effects that arise when certain activities are done in excess or incorrectly (e.g. excessive or incorrect exercise routines). Guidelines would also increase the likelihood that the activities will be optimized to achieve their intended benefits. More importantly, the guidelines could include reminders about the importance of healthy use of, or exposure to social media and news [54, 55], diet, sleep hygiene recommendations (e.g. reducing or minimizing exposure to light sources before going to sleep), and sensible consumption of substances such as alcohol or caffeine.

There is a need to update this synthesis on a regular basis with results from identified studies that will be published in the next few months and beyond. Studies that use strategies and outcome measures that are less susceptible to self-reporting biases would also help increase the validity of evidence for these activities. Finally, for a medium to long term perspective, a synthesis of current systematic reviews or a meta-review would help identify a wider range of mental health promoting activities that could be rigorously tested during the ongoing and perhaps recurring pandemic periods.