Rachel Ashe has always struggled with her mental health. But after a particularly vile year, she impulsively took part in the Loony Dook, a New Year’s Day swim in the chilly Firth of Forth in Scotland. “I hated it!” she says. “But afterwards, I felt just a little glimmer of hope.”

On her return home to Swansea, that glimmer was enough to motivate her to take to the water again and invite others experiencing mental health challenges to come along. Five years on, Ashe, who has complex mental health issues, an autism diagnosis and attention deficit hyperactivity disorder, heads up Mental Health Swims, a peer-support community with 140 groups across the UK.

The free sessions take place once a month and are run by one of more than 400 trained volunteer “swim hosts”. “The structure is always the same: we dip, have a chat and do a litter pick – but there’s no pressure to do any of it, no emphasis on time, distance or progression,” Ashe says. “We’re about short dips, not long distances; community, not competition.” About 75% of participants say their mental health has improved since joining.

Mark Harper, director of Mental Health Swims, who studies the effects of cold-water immersion on anxiety and depression at Brighton and Sussex University Hospitals and is the author of Chill: The Cold Water Swim Cure, isn’t surprised. “Our studies have shown a meaningful reduction in depression from swimming once a week,” he says. His maxim is “not that long, not that often”, and this approach is rising to prominence in encouraging people with mental health problems to experience the benefits of being active.

Siobhan Miles, 64, stopped running with her local club when she found it was hurting her knees and feet and she could no longer keep up. “I realised then how important moving outside was to my mental health,” says the financial analyst. “Now I start the day with a half-mile mindful walk, noticing and appreciating my surroundings. I can’t tell you what a difference it has made to my perspective on what really matters in life.”

None of these exercise regimes would meet the physical activity guidelines issued by national and global bodies, which set out the amount of exercise “required” for physical and mental health. For adults aged 18-64, the latest World Health Organization (WHO) advice recommends “at least 150-300 minutes of moderate-intensity aerobic activity, or at least 75-150 minutes of vigorous-intensity aerobic activity, or an equivalent combination throughout the week” – along with muscle strengthening activities that involve all major muscle groups at moderate or greater intensity at least twice a week.

But briefer or gentler bouts of activity can still have a positive impact on mental health. Some experts believe there is a risk that, faced with such rigorous and prescriptive guidelines, people experiencing mental health challenges may be put off being active at all. “Given that people with mental health issues are typically less active than the population average, it is even more important to present exercise as a positive, enjoyable and accessible option,” says Stuart Biddle, professor of physical activity and health at the University of Southern Queensland.

For Ashe, the focus on quantity is not helpful. “Obsessing over distance, speed and amount per week takes the enjoyment out of the movement I am doing,” she says. “The reality for a lot of people experiencing mental health issues is that things can be very up and down. What we’re able to do one week can differ hugely from the next. Failing to reach a nationally prescribed number of rigorous exercise minutes is just another reason to feel bad about yourself.”

Exercise guidelines were first issued in 1975, with the aim of preventing cardiovascular disease. While their scope has now widened to include other physical conditions as well as cognitive and mental health, Panteleimon Ekkekakis, professor of exercise psychology at the department of kinesiology at Michigan State University, believes it isn’t rational to apply guidelines that were developed for cardiovascular health to mental health. “We do know that exercise is good for mental health,” he says. “But we don’t see the same clear dose-response relationship that we see with physical health – it’s too individual and there are many contextual factors that go beyond issues of quantity.”

In 2022, Brendon Stubbs, a physical activity and mental health researcher at King’s College London, conducted research in conjunction with sports brand Asics into the emotional and mental responses to movement in 1,000 people. Often, this type of study relies simply on asking people how they feel, before and after, but Stubbs also used electroencephalogram tests to monitor their brain activity. “We found that 15 minutes was the point at which people began to experience the uplifting effects of exercise, dispelling the notion that long periods of activity are needed in order to get a positive impact on mental health,” he says.

There is plenty more where that came from. A 2023 study, published in the British Journal of Sports Medicine, gathered evidence from 97 reviews and found that, regardless of type and dose, movement was beneficial for depression, anxiety and psychological distress. Anything from tai chi to weight training, dance to running, yoga to walking worked, though “effect size” – the measured impact on mental health – varied. For example, strength-based exercise was found to be the most clinically meaningful (impactful) on depression, while yoga and other mind-body activities had the most significant effect on anxiety.

Meanwhile, a recent meta-analysis published in the Journal of the American Medical Association found that meeting the WHO guidelines reduced the risk of depression by 25%, while doing half the amount still reduced the risk by 18%. “These findings are particularly important when you consider that people who are experiencing – or at risk of – mental ill-health are more likely to be physically inactive, and more likely to prefer lower-intensity activity,” says Megan Teychenne, associate professor at the Institute for Physical Activity and Nutrition at Deakin University, Australia. “Getting out for a walk twice a week may not tick the physical activity guidelines, but it has been shown to yield mental health benefits.”

Teychenne was one of the contributors to a “consensus statement” entitled Optimising the Mental Health Benefits of Physical Activity, issued by the Australian Psychological Society and Sports Medicine Australia last year. It highlights ways in which the current guidelines could be adjusted to promote mental health and wellbeing.

One is to shift the focus from quantity to quality. “Alongside issues of ‘how much, for how long, and at what intensity’ we need to consider the ‘where, when, what, and with who’ of physical activity,” says Prof David Lubans, who contributed to the statement and is co-director of the Centre for Active Living and Learning at the University of Newcastle in New South Wales.

“Is it something you’ve chosen to do in your leisure time, or something you have to do at work or school? If it’s in a social setting, do you feel connected with others, do you feel valued and supported? What is the physical environment like? All of these can significantly influence mental health outcomes.”

Exercise affects the brain not just through neurobiological mechanisms but also psychological, behavioural and social ones. A US study, published last year, found that a reduction in anxiety and depression among people who had returned to physical activity after the Covid lockdowns could only be partly explained by the increase in exercise, and was more attributable to social connection and other psychological factors.

Biddle has been involved in the development of physical activity guidelines for more than four decades. He welcomes the recent consensus statement. “I would like to see more emphasis on mental health in the guidelines,” he says. “They are strongly oriented to physical health outcomes, such as cardiovascular disease and diabetes, where there is a clear dose-response relationship. There’s a lot more variability when it comes to the relationship between physical activity and mental health than there is in terms of say, diabetes. It’s more individualistic, more nuanced.”

However, Biddle wonders whether, rather than studying dose-response relationships to the nth degree, the more important question is how we actually get people – regardless of their mental health status – to engage in the physical activity that will benefit their overall health and wellbeing.

According to a 2022 global report by the WHO, 36% of adults in the UK do not meet the physical activity targets. Among adolescents, the figure is much worse: only one in five of those aged 11-17 achieve the 60 minutes a day recommended for this age group. Meanwhile, 8.7 million – just over 15% of people in England – received antidepressant medication in the year to March 2024, a number that has risen year on year since 2015.

So how can the guidelines be better geared towards helping people get active for mental health and wellbeing? “We need to be kinder with our messaging,” says Stubbs. “It’s a win if you can do something. Forget about the minutes and the intensity – not everyone is going to achieve 150 minutes a week.”

Teychenne’s advice is to “prioritise physical activity that you enjoy and have personally chosen to undertake. You are more likely to gain mental health benefits – and more likely to stick to physical activity – if you’re doing something you enjoy.”

That might sound obvious, but Ekkekakis says pleasure has been woefully disregarded in the public messaging. “Think about how exercise is presented in western society,” he says. “It’s not ‘fun’, it’s not ‘family time’, it’s not ‘time outdoors’ – it’s ‘medicine’ that will do you good; it’s the price you have to pay for succumbing to the pleasures of eating. Even the words used in the recommendations, like ‘dose’ and ‘prescription’, have negative connotations.”

Ekkekakis believes the guidelines are based on a flawed understanding of human behaviour. “The assumption underlying them is that we are rational beings, driven only by information,” he says. “But this is not how the human brain works. What we know and how we act do not always align, because we are motivated by other factors than information.”

Ekkekakis’s research over the past two decades has identified that having an element of free choice (autonomy) plays a key role. In his most recent study, gym-goers who were encouraged to regulate their exercise intensity with the goal of maintaining enjoyment, not effort or heart rate, rated the experience far more favourably than those following standard exercise-intensity guidelines. They also performed 77% more sessions over the eight-week follow-up period than the control group.

In Stubbs’ study – in which 15 minutes was shown to be enough to get a mood boost from movement – neither the type of exercise nor the intensity was prescribed. People could choose any type of movement and make it as hard or easy as they liked, which probably contributed to the sense of wellbeing they derived from it.

A similar philosophy underpins Green Gym – a nature-based volunteering initiative with 60 sites across the UK, run by the Conservation Volunteers. “Activities range from weeding and pruning to digging and planting – and everyone is free to choose how often they come, and what, how much or how little they do,” says Abi Townsend, London operations leader. “Our emphasis isn’t on output. It’s about being part of a community, getting active and being in the outdoors.”

In a survey earlier this year, 94% of Green Gym-goers said that taking part had improved their wellbeing; a similar number said it had increased their connection to other people and to nature, and 87% said it had made them more physically active. It is an example of how, when delivered appropriately, physical activity can work wonders on mental health. But the reverse is also true. “Poorly designed physical activity programmes can have negative effects on mental health,” says Lubans.

For example, in exercise or sport environments in which success, as opposed to effort, is praised, or where participants are left out, shamed or humiliated for making mistakes, physiological and psychological stress increases. Ringing any bells?

For most of us, the first experience of organised physical activity comes at school. Often it’s not an experience that we remember fondly – and this matters. In a study of how childhood experiences determine attitudes to physical activity in adult life, one participant said: “PE robbed me of the joy of physical activity for many years. It destroyed my physical confidence.”

“If we ask ourselves, as a society, if we’ve ever tried to make people’s experiences of physical activity pleasant, I think the answer is no,” says Ekkekakis. “It is no wonder that when we hit mental health roadblocks, we don’t turn to physical activity for solutions.”

At least now there is growing recognition that exercise, or physical activity, or movement – whatever you want to call it – does not “happen” only to our bodies but to our minds, too. “The notion that ‘exercise is medicine, it doesn’t matter how you take it’, might be fine for cardiovascular health, but when it comes to mental health, it just isn’t good enough,” says Lubans.

How to keep on moving

Prioritise pleasure
Aim to make physical activity pleasurable, says Ekkekakis. “If music makes the experience more pleasant, or gamification, use it. Maybe it’s the presence of a good friend – but if their presence forces you out of your comfort zone, or creates competition that you don’t enjoy, avoid it. You always want the answer to the question ‘Was this a good experience today?’ to be yes.”

Finish on a high
Behavioural economics examines which aspects of an experience are the most consequential in terms of how it is remembered and judged. Research shows that our views are particularly coloured by the last part of an experience – so make sure that bit feels good. A great reason to do a cooldown.

Move outside
“Setting can play a key role in how you feel when getting active,” says Hayley Jarvis, head of physical activity at mental health charity Mind. Movement in pleasant natural surroundings has been shown to have a greater impact on mental health than exercising indoors or being sedentary in nature: “The colours, sounds and smells we encounter outdoors stimulate our senses in a way that the gym or urban environments do not.”

Park your goals
Don’t worry about daily or weekly targets if you are struggling mentally. Lubans says recent evidence suggests that for people who are not already active, open goals – in which you simply begin, and see how you get on – are more effective.

Find the right instructor
A good coach, teacher or instructor should support, rather than undermine, your confidence. The emphasis should be on fun and participation.

Be kind to yourself
“Experiencing poor mental health can bring additional barriers to getting active,” says Jarvis. “There are times when even getting out of bed can feel like an achievement. Remember that even small amounts of physical activity can bring benefits.”