Interview conducted by April Cashin-Garbutt, BA Hons (Cantab)
Please could you describe what mental health benefits can result from exercise?
Perhaps we should first of all clear up the definition of exercise. In public health terms it is more common to use the phrase ‘physical activity’ because this phrase encompasses all kinds of movement- indeed anything we do above sitting and resting levels. This can include walking, gardening, playing sports, dancing even doing the housework! But it also includes more structured forms of movement in which the person is taking part for health and fitness gains – and this is the definition we usually reserve for exercise. Typical exercise activities would include going to the gym, running or jogging, cycling and swimming.
Now the point of this long winded beginning to the answer is that a lot of the evidence you are asking about relates to the wider definition of physical activity. For example, at the level of large population surveys, we know that there are strong association between physical activity and well being – meaning the more active people report higher levels of well-being. There are also inverse associations between physical activity and depression – meaning that those with higher physical activity levels report lower depression scores.
However, in more formal studies which try to go beyond the associations to determine cause, people are often asked to exercise rather than simply increase their physical activity. In such studies a consistent finding is that exercise appears to be causally related to decreasing levels of depression. A newer set of findings relates to exercise preventing cognitive decline such as the onset of dementia. For children a consistent finding is that physical activity is related to higher levels of self-esteem.
How much exercise is necessary to derive these benefits?
It would appear that for the dose of exercise required to gain mental health benefits is similar to that suggested for general health benefits – that is for adults to accumulate over the course of the week at least 150 minutes of moderate intensity physical activity and for children to accumulate 60 minutes of moderate intensity activity most days of the week.
Please can you explain the mechanisms by which exercise can cause mental health benefits?
At this moment in time there is no clear answer to this question. A number of plausible explanations have been put forward. Some of these explanations are more psychological – for example by exercising we feel that we are doing something good for ourselves, we might perceive we are getting fitter and stronger and this improves our feelings of worth.
Other explanations are more neurological – for example when we exercise we release a variety of chemicals in our brains that are responsible for how we feel. The most common example of this is that when we exercise we release endorphins and these chemicals are related to the feel good effect many people report when they exercise. However, the technology of determining what is happening in the brain while we exercise is still at early stages so this remains more of a hypothesis than a fact. There may be other mechanisms at play as well if the person is exercising with a group and social benefits are perceived.
The possibility exists for all these plausible mechanisms to be occurring at the same time in a synergistic way and so I doubt that there is one single mechanism that is responsible for people feeling good or feeling less depressed when they exercise.
Please can you tell us about your research into the impact structural changes to the environment can have on walking and cycling?
Walking and cycling for transport might be the best possible way to get more minutes of activity into a person’s day. With the goal of achieving 150 minutes of moderate activity over the course of the week, 15 minutes walking from a bus, train or car parking space to and from work each day would help us reach that target.
In most cities and towns it is possible to walk safely if there are pavements and they are in good repair and well lit, but in most cities and towns there are no special routes for bikes. This means that many people are put off cycling because they perceive it to be dangerous. We know that there are strong associations between people’s perceptions of the environment as being safe and pleasant and their walking and cycling behaviour.
What we do not know is that if we improve the environment will more people walk and cycle? In the Netherlands and Denmark for example, where almost a third of the population use a bike for transport, there are bike lanes separated from traffic and plenty of safe places to lock the bike up.
I am currently part of a big project called iConnect. In this project we are evaluating the impact of changes to the structure of the environment, for example a new bridge over a busy road or the completion of a path over tidal water. In addition we are testing the idea that by providing information and motivation to use these new structures we can influence even more people to try walking and cycling for transport or for recreation.
How else can we encourage people to be more physically active?
I firmly believe that for most sedentary people, who do not think of themselves as ‘sporty’, and who would like to become more active and get fitter, then the best start point is to add 10-15 minutes of walking into 3 days next week and then try to build it up from there. Walk a bit to work, walk more with the dog, walk with the kids to school or walk to the shops – that all counts and is easy to build up over time.
Why are some people harder to encourage to be physically active than others? How can the less inclined people be encouraged to exercise?
Many people have negative memories of PE at school; others do not find sport or gym exercise appealing. As suggested above walking is the best start point in my view, but the trick is to find someway of moving about that is fun….some people can find that through gardening, others through dancing, others maybe playing more with the kids or grandchildren. I doubt if this can be true myself but some people have become more active by doing more housework more often!
What plans do you have for further research into this field?
We are currently working on projects that: encourage people to walk some or part of the way to work; that encourage people with learning disabilities to put some walking into their day; that investigate if teenage girls could be encouraged to walk more and to determine if football fans can get more walking into their week. Walking is it!
Would you like to make any further comments?
Walking provides the best bet for helping most people find a space in their lives to increase physical activity levels and gain the many health benefits that know comes from regular activity. The most immediate benefit – even after one 10 minute walk- might be that people feel better. The ‘feel good’ effect is something we can all do with!
Where can readers find more information?
Global Advocacy for Physical Activity
Iconnect: Impact of COnstructing Non-motorised Networks and Evaluating Changes in Travel
Football fans in training
About Professor Nanette Mutrie
Nanette Mutrie, Ph.D., is Chair of Physical Activity for Health, University of Edinburgh, Scotland. She has researched ways of increasing active living with a particular interest in the mental health benefits.
Current funded projects include:
the Scottish Physical Activity Research Collaboration [SPARColl funded by NHS Scotland; www.sparcoll.org.uk]
the promotion of walking with the use of pedometers for older adults and people with learning disabilities [funded by the Chief Scientist’s Office]
the evaluation of the impact structural changes to the environment on walking and cycling [funded by the Engineering and Physical Sciences Research Council; http://www.iconnect.ac.uk/]
Nanette is an Accredited Sport and Exercise Psychologist with the British Association of Sport and Exercise Science (BASES) and is an Honorary Fellow of that organisation. She is also a Chartered Psychologist with the British Psychological Society.
With her students and colleagues, she has published over 100 peer reviewed articles on exercise behaviour and intervention strategies.
Nanette has editorial roles for The Journal of Physical Activity and Health and Mental Health and Physical Activity and has also contributed to policy, for example, ‘let’s make Scotland more active’ and the National Institute of Health and Clinical Excellence [NICE] programme on physical activity and the environment [www.nice.org.uk].