As a nation we are becoming more sedentary, more obese and more depressed. An estimated 22 per cent of the UK adult population is classed as obese and as many as one in four is likely be affected by a mental health problem at some point in their lives.

At the dawn of a new decade, there is no better time to kick-start a healthier lifestyle.

We all know exercise is an essential part of a healthy lifestyle. As well as burning calories, aerobic activity results in the release of endorphins, which make us feel happier. Getting into a routine of regular exercise can go a long way to combat both depression and obesity and to greatly reduce the risk of death from heart disease.

Whilst any activity that makes you warm and raises the heartbeat will help shed the pounds, growing medical evidence shows that activities out in nature are most beneficial, improving health and wellbeing, preventing disease and aiding recovery from illness.

A team of researchers from the University of Essex has been studying the effects of various outdoor activities on mood.

Participants were found to be significantly less depressed and had higher self-esteem after engaging in outdoor activities.

“Whether you take a bike ride, join a walking group or plant bulbs in a garden, being active outdoors has been proven to benefit mental and physical health,” reports Professor Jules Pretty, who leads the team of researchers.

So, with the clear message to take your exercise out to the great outdoors, where do you begin?

For many of us, joining an established group is the best motivator. Socialising with others is also a mood-lifter and people with good social networks tend to enjoy better health. A good way to meet people whilst getting fresh air and exercise is to become a conservation volunteer, and there are plenty of opportunities in Oxfordshire.

The Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust (BBOWT) runs regular work parties in several reserves across the county.

Katie Fenton, manager of Sutton Courtenay Environmental Education Centre, near Didcot, organises a number of regular volunteer groups.

She said: “Volunteer groups come in fortnightly on Mondays and Fridays and monthly on Sundays. They do a range of essential jobs from maintaining our wildlife garden to clearing scrub and digging wildlife ponds.

“Their help and expertise enable wildlife to flourish and offer an opportunity for volunteers to acquire new skills and meet new people.”

For the volunteers, the benefits are many. John Bentley, now retired from the IT industry, is a regular on BBOWT conservation teams. “After retiring I wanted to keep active and do something to help the environment,” he said.

“BBOWT had opportunities close to where I live, so I went along and have since made many new friends, worked in some beautiful countryside and had a lot of fun.”

If scrub clearance or pond de-sludging is not for you, there are also opportunities for less strenuous activities such as keeping tabs on the grazing stock on nature reserves.

John Bentley regularly visits his local BBOWT reserve to make sure the resident sheep are healthy, have water and that the fences are secure.

He added: “It’s really just being an extra pair of eyes for the reserve wardens. It gives me a reason to get out for a walk and helps the wildlife trust with their important work.”

The British Trust for Conservation Volunteers (BTCV) operates a ‘Green Gym’ scheme, with a focus on improving the physical health and well-being of those involved.

Starting out as the idea of a local GP from Sonning Common over ten years ago, the scheme is now active across the country. Five groups operate in Oxfordshire with activities to suit all levels of fitness. Tasks such as digging out ponds and driving in fence posts give a heavy work-out, whereas nailing slats to a boardwalk or pruning overgrown footpaths is steady but lighter work.

One volunteer, who joins in at Withymead Nature Reserve, near Goring-on-Thames, said: “With so many different things to do and such beneficial results, it’s not surprising that everyone has a smile on their face when they’re working here.”

There are also programmes that simply encourage people to get outside. Natural England has a Walking for Health programme, devised in partnership with healthcare practitioners. This aims to encourage people, particularly those who take little exercise, to do regular short walks in their local community. A number of local health walks meet on a regular basis across Oxfordshire, including in Oxford city centre.

The healing effect of nature is not limited to exercise alone. There is evidence to suggest that simply looking at fields or gardens can have a beneficial effect on health.

Research from the 1980s shows that patients recovering from operations did so more quickly if they looked out on to green spaces from their hospital bed — a finding that is now often taken into account when designing new hospitals.

The effect of nature on our health is so compelling that the mental health charity Mind is calling for a new green agenda for mental health. Mind is campaigning for health practitioners to be able to offer sufferers of mental illness accessible, cost-effective, natural alternatives to existing treatment options, for example joining a walking group or community gardening project.

The temptation to stay indoors in this miserable weather can often be overwhelming but getting out into nature and being active can brighten up some of those miserable winter blues.

To find out more about how to join or volunteer for BBOWT go to www.bbowt.org.uk