According to a study exercising outdoors relieves stress more than working out indoors.
Mountain biking and running in landscapes without any buildings were found to have the biggest positive impact on mental health.
Psychologists believe it’s the calming effect of nature that makes outdoor exercise so stress relieving.
The research adds to a swathe of studies that have found exposure to green space is beneficial for our mood.
Experts at the University of Roehampton along with a team in Germany, published their findings in the journal Mental Health and Prevention.
The team led by Dr Sandra Klaperski asked 140 participants to report on their mood, stress levels and feeling of anxiety before and after exercise.
The participants had to regularly take part in either an indoor sport – aerobics, aqua aerobics, basketball, fencing, swimming or volleyball – or an outdoor sport – running, football or mountain biking.
The football took place on a green lawn field with buildings on the one side and a view on a river and a forest on the other side.
The running and mountain bike groups had views of a hilly forest with hardly any urban views, the researchers said.
The questionnaires the participants answered consisted of a total of 54 items with a five-point scale.
For example, they rated how strongly they agreed with the statement, ‘Right now I feel energetic’.
In addition to the mood, anxiety and stress scales, the post-questionnaire assessed the naturalness and calmness of the environment.
Overall, all exercise methods improved mood, stress and anxiety, which supports a plethora of evidence that shows exercise can boost mental wellbeing.
The study found working out in environments perceived as more calming – notably outdoor and green spaces – had a greater impact on stress than exercise in indoor spaces.
The indoor group reported stress levels of 2.42 out of five before exercise, which reduced by eight per cent to 2.23 after exercise.
Whereas the outdoor groups’ stress levels reduced by 13 percent, from 2.35 to 2.05 out of five.
Only one indoor exercise was found to significantly improve mood and stress, which was swimming at a reduction of 11 percent.
An aerobics class indoors, which could be anything from cardio, circuits of HIIT – reduced stress by seven percent.
Mountain biking improved stress more than other forms of exercise, with participants rating their stress 18 percent lower after taking part.
However, running came out top because it improved all four mood outcomes – restlessness, bad mood, stress and anxiety.
A run improved restlessness and bad mood by around 27 percent, stress by 14 percent and anxiety by 16 percent.
The authors wrote: ‘This could nonetheless suggest that green exercise, and running outdoors in particular, has stronger positive effects on acute mood and perceived stress levels than non-green types of exercise.’
The researchers note that it may simply be a ‘calm environment’ while exercising that reduces stress, which correlates with green spaces.
Therefore, places like gyms could reduce noise level to make sure the room is still perceived as calm, the researchers suggested.