The Daily Telegraph reports that five minutes of exercising in the countryside rather than an urban gym gives a boost to mental health. According to the paper, a recent study has found exercising in wilderness areas or near water has the biggest impact on one's mental state, with the greatest health changes to be seen in the young and the mentally-ill.

The news report has been based on research pooling the results of ten University of Essex studies on how exercising outdoor in green surroundings affects one's self-esteem and mood. The study has a number of limitations, as all the studies were conducted by the same institution, including the fact that none of the studies had a control group, meaning whether these improvements would have occurred naturally over time, or if gym exercise or other leisure activities would have similar results, remains unclear.

Physical activity has been proven to be not only beneficial for one's physical health, but also mental health. Ideally, individuals should participate in physical activity that they enjoy, which may include outdoor exercise.

Dr. Jo Barton and Professor Jules Pretty from the University of Essex conducted the research, which has been published in the journal Environmental Science and Technology.

This study is a meta-analysis of the pooled results of 10 previous studies involving 1,252 volunteers, on the effects of `green exercise' on mood and self-esteem that the University of Essex carried out over the past six years. Researchers defined green exercise as activity in the presence of nature.

They looked at how the results of the studies were affected by the location of the exercise, individual's age, gender, and whether they had any mental health problems.

Volunteers comprised of people already opting for green exercise in environments, including urban parks, countryside, farmland, forest and woodland, waterside areas and wild habitats, members of a local mental health association (Mind), allotment holders, young offenders and students. Exercise activities included walking, cycling, fishing, boating or sailing, horse-riding, farming activities and gardening.

All ten studies looked at participants' mood and self-esteem immediately before and after green exercise. The analyses looked at different durations of exercise: 5 minutes, 10 - 60 minutes, half day, or whole day.

The meta analysis indicated green exercise was associated with statistically significant improvements in self-esteem and mood, with slightly larger improvements seen in mood than self-esteem.

These improvements were greatest with five minutes of green exercise, while there were smaller benefits from longer exposures, such as, 10 minutes to a whole day. Light intensity activity had the greatest effect on self-esteem; light activity and vigorous activity had similar effects on mood, with less effect seen for moderate activity.

All of the green environments had a positive effect on self-esteem and mood. The greatest effect was seen in environments featuring water.

Green exercise had a similar effect on self-esteem and mood for both men and women. People with self-reported mental health problems showed greater improvements in self-esteem with green exercise than those without such problems. However, they showed no difference in improvement in moods. Those under 30 showed the greatest improvements in self-esteem, while those aged 31 to 70 years old showed the greatest improvement in mood.