By Philipp Beranek and Dr Ian C Dunican 

Sleep impacts how we feel and perform at work or other tasks [1-3]. Sleep is also crucial for our health, such as mental health [4]. Yet, many people regularly experience sleep difficulties [5]. These can include difficulty falling asleep or frequent awakenings throughout the night. Multiple factors can cause these sleep difficulties. For instance, work-related stress, alcohol consumption, or pain can result in short sleep and poor sleep quality [6]. Sleep hygiene guidelines involving behavioural strategies and environmental factors are recommended for improving sleep [7]. For instance, avoiding caffeine within 4 hours of bedtime and creating a dark sleep environment can be beneficial for sleep [8]. Researchers continue to investigate what factors may influence our sleep.

One such example is

“Do we sleep longer and better when we spend more time in green spaces, such as parks and natural environments?

Evidence shows the beneficial effects of green space exposure on mental health and physical activity levels [9]. However, do green spaces have additional benefits such as better sleep? In this blog, we look at the evidence and delve into the impact of green space exposure on sleep.

Green space exposure and sleep

Research on green spaces and sleep is scarce. However, the existing literature reveals a interesting link between green spaces and sleep [10]. In particular, study results have shown that adults who lived in an area with a greater green space percentage (e.g., 80% vs. 20%) had a reduced risk of short sleep (e.g., < 6hrs) [11]. Similar findings were observed in children. Children with limited access to parks presented a 1.2 times greater likelihood to experience at least three days of short sleep per week [12]. Interestingly, one study observed the same link for sleep on weekdays, but not for sleep on weekends, this may be attributed to social and behavioural factors [13]. These initial studies suggest that green space exposure has a beneficial effect on sleep, particularly on weekdays. To date, the responsible mechanism for better sleep with a greater green space percentage is unclear. However, authors have discussed that green space exposure may facilitate good mental health, regular physical activity, and social cohesion, which all have been previously linked with good sleep [13]. The exposure to natural light in these greenspaces may also support mental health and good sleep. Researchers analysed data from the UK Biobank cohort, a large study conducted in 502,000 adults of the UK general population. They observed a positive relationship between outdoor light exposure and mood and sleep outcomes [14]. These results indicate beneficial effects of outdoor light exposure during the day on mental health and sleep.

Activities in green environments have been suggested to be beneficial for sleep [10]. Two hours of forest walking has been shown to improve sleep duration and self-reported sleep quality in healthy adults with sleep complaints [15]. One study observed long-lasting positive physiological effects on the autonomic system during sleep after a 1.8 km walk in a green environment compared to an urban environment, potentially enhancing the restoration effect during sleep [16].  Can’t get outside, don’t worry as indoor gardening for four weeks (every morning and afternoon) had a beneficial effect on sleep in people with dementia [17].

The research shows promising results for the beneficial effects of green space exposure on sleep. However, it is important to acknowledge that not all studies found a link between green space exposure and sleep. For instance, one study investigated the relationship between the type of land use (commercial, residential, industrial, green space) and the sleep of 2,411 participants [18]. Green space was not independently linked with better sleep outcomes. The study results suggested that noise and traffic levels were mediators for the associations between land use type and sleep outcomes [18].

Practical applications

How can you apply the study findings to improve your sleep?

1. Dedicate time to green spaces.

Incorporate exposure to green spaces into your routine. Make an effort to regularly spend time in parks, gardens, or natural settings. This can include a morning walk in the local park, lunch in a green space near work, an after-work run in the forest on your way home, or working on your garden at home. Weekends are suitable for more time-consuming activities, such as hikes or longer walks in national parks, as it may be easier to dedicate more time to them. If the time allows, weekend getaways are an excellent way to spend more time in nature.

2. Join organised activities in green spaces

Many communities offer regular activities in green spaces, such as walking groups or running clubs. These activities provide excellent opportunities to be physically active, socialise, and be in green spaces at the same time. An example is the popularity of parkrun. Parkrun organises weekly free community events in 20 countries. Parkrun events involve either walking, jogging, or running a 5km course (2km for juniors) with the local community at the local park. Find a parkrun event near you at www.parkrun.com.

3. Organise activities in green spaces

If not enough activities are offered near you, organise regular activities in green spaces with your family, neighbours, friends, or co-workers.

Conclusion

The research on green space exposure and its effects on sleep is promising, albeit complex. Whilst the mechanisms are unclear, positive findings from multiple studies suggest that spending time in green spaces can enhance our sleep quality and duration. These findings encourage people to spend more time in green spaces by incorporating them into their routines. Joining organised activities, regularly organising activities with like-minded people, and weekend getaways or excellent opportunities to spend more time in green spaces.

References

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15. Morita, E., et al., A before and after comparison of the effects of forest walking on the sleep of a community-based sample of people with sleep complaints. BioPsychoSocial medicine, 2011. 5(1): p. 1-7.
16. Gladwell, V.F., et al., A lunchtime walk in nature enhances restoration of autonomic control during night-time sleep: Results from a preliminary study. International journal of environmental research and public health, 2016. 13(3): p. 280.
17. Lee, Y. and S. Kim, Effects of indoor gardening on sleep, agitation, and cognition in dementia patients—a pilot study. International Journal of Geriatric Psychiatry, 2008. 23(5): p. 485-489.
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