“Our health-related behaviours can also help us to mitigate climate change and to adapt to it”

Interview by Yvette Moya-Angeler

We spoke to Guillaume Chevance at ISGlobal’s offices in Barcelona while he was visiting the city. Last autumn, Chevance moved to Saillagouse, a village in the French Cerdagne situated close to the Spanish border so he had taken the early morning train to Barcelona. On the coast of the Mediterranean, the day was turning out to be hot and humid but Chevance, a Breton from Saint-Brieuc, explains he is more than familiar with this kind of muggy weather from his university days, when he lived in Montpellier. At thirty years of age, he has just become a father for the first time, and he proudly informs us that the baby is a boy and they are calling him Maël.

Chevance’s first degree was in Physical Exercise and Sports Sciences and Techniques (STAPS-APA) and he received his PhD in Human Movement Sciences. On completing his doctorate he moved to the United States to work as a postdoctoral researcher at the University of California, San Diego (UCSD). The focus of his work at San Diego was the use of digital devices (phones, smart watches, etc.) to help people change their health-related behaviours and lead more active lives, adopt a healthier diet, and sleep better.

In October 2020, he moved to ISGlobal to coordinate the eHealth group, part of the institute’s Severo Ochoa research programme. His main interest at present is to gain a better understanding of how health-related behaviours are changing in response to the effects of climate change, which are already disrupting our routines.

A. Cabrera / ISGlobal

You describe yourself as a behavioural scientist. What does that mean?

My main area of interest is how to change behaviours, especially health-related behaviours. Most of my research seeks to understand the different ways each one of us behaves and how our personal behaviour also varies according to the circumstances. Let me explain. Everyone is different—what motivates you to exercise may not motivate me, or what helps you to sleep well may not help me. However, the context is important too—maybe you’ve just started a new job or it’s very hot in the city where you live. All these external factors influence the way you behave. For example, you won’t act the same way when you are alone as you would if you were with other people and you don’t do the same things on a sunny day that you do on a rainy day. When the context changes, our behaviour changes too. In our research, we try to disentangle this rather complex knot. We are interested in finding out, for example, why some people are more active at certain times, or why some people sleep badly in certain situations.

We have not, as yet, achieved a good understanding of the factors that lead people to change their behaviours. When we find out what those factors are, we will be in a position to help people to improve their diet, exercise more, sleep better... and to prevent many non-communicable diseases.

And why do you want to understand these variations? What is the purpose of this research?

Understanding how people behave is crucial in health care. We know that physical activity, adequate rest and a healthy diet are all factors that protect us against cancer and metabolic disorders. But we have not, as yet, achieved a good understanding of the factors that lead people to change their behaviours. When we find out what those factors are, we will be in a position to help people to improve their diet, exercise more, sleep better... and to prevent many non-communicable diseases.

Using interventions tailored to the individual?

Yes. Using devices such as smart phones and digital monitoring devices (smart watches, for example), we can collect a huge amount of data on the health habits of the people who take part in our studies. Using this data we can create statistical models designed to provide information about why certain strategies seem to work for some people. This in turn will help us to design individualized or targeted interventions for certain groups of people.

A. Cabrera / ISGlobal

Understanding why we stop exercising

What got you interested in health-related issues?

I did my masters degree in Human Movement Sciences at the University of Montpellier in France and at the end of the course I worked in a hospital. My main responsibility there was to promote physical activity among people with chronic diseases, and particularly those with metabolic disorders. So I designed physical health programmes for those people and the programmes worked well: in five weeks, the patients improved their physical fitness and felt happier. But once they had completed the programme, they failed to maintain the same level of physical activity. As a result, I developed an interest in understanding the psychology of why people give up their health programmes. I did a second masters, this time in Health Psychology—also at the University of Montpellier—and I went on to do a doctoral thesis on the role of motivation in the adoption of an active lifestyle in people with chronic diseases.

What motivates you to lead a physically active life?

It depends on the activity. For example, before I came here I lived in California for a few years and did a lot of surfing. In that situation, the social component was important: the fact that I surfed with friends. In fact, it was essential because I often had to get up very early to take advantage of the best time of day to surf and the fact that there was someone waiting there for me helped to get me out of my bed. Now that I am living in the mountains, I don’t need to motivate myself because after I’ve spent the day sitting in front of a computer, the thing I most feel like doing is going outside for a run.

Going beyond the motivational determinants of behaviour, I have broadened the focus of my research to include environmental conditions as well—the place where someone lives, the level of pollution in the air they breathe, and so on. It is interesting to study the question of whether climate influences our motivation. In places where it rains a lot, for example, or where it is very hot people feel less motivation to exercise.

It’s strange: you work with a lot of data and technology, but your work is actually about psychology.

Psychology is highly quantitative; we deal with a lot of data and statistics. But my focus now is not solely on the psychological aspects of the question. Going beyond the motivational determinants of behaviour, I have broadened the focus of my research to include environmental conditions as well—the place where someone lives, the level of pollution in the air they breathe, and so on. It is interesting to study the question of whether climate influences our motivation. In places where it rains a lot, for example, or where it is very hot people feel less motivation to exercise. My experience as a scientist is multidisciplinary and my work involves a wide variety of aspects. So it is hard to define what I do with a single label.

How are you applying this approach at ISGlobal?

Right now I am working on how human behaviours can serve to mitigate or reduce climate change and also help us adapt to the evolving situation. In the case of mitigation, one line of research focuses on how we can help people to eat a healthy and sustainable diet using text messaging or an app on their mobile phones. In the area of adaptation, we want to see to what extent heat waves affect physical activity and the quality of sleep, because these hot spells will be increasingly frequent, especially in cities like Barcelona. What can we do to get people to continue their physical activities during these periods? And how can we help the most vulnerable populations—older people, people with underlying conditions, etc?

A. Cabrera / ISGlobal

A very old cell phone

And for all of this you use technology.

Yes. A practical example. To measure the impact of temperature on a person’s behaviour, we can use a mobile phone app that sends its GPS location every 10 to 15 minutes. That provides us with information on the temperatures the phone has been exposed to. And a smart watch that can detect movement provides data on the person’s physical activity: how hard they have exercised, etc. The watch can also tell us whether the person has slept well or woken up many times during the night. Once we collate all these data, we can link the two datasets: activity and temperature.

Do you see a future in which we will be continuously monitored, generating a large volume of individual data?

I am not sure I do. I use digital tools and devices to better understand how people behave, but I don’t always promote them. In fact, I personally have a very old mobile phone and I don’t use much technology. Fitness tools on mobiles and smart watches are useful for increasing scientific knowledge and occasionally—only occasional—they can also be practical. When they are useful, they can be very good. Sometimes they help people to modify their behaviours.

Do you design applications aimed at doing that?

Sometimes, but you can use the ones that already exist. We are currently preparing a study on sustainable diets: for six months, we will send participants a questionnaire every week by SMS asking them what they eat. This will provide us with a great deal of data. We will also send them motivational messages, recipes, and so on. Those are easy solutions, which can be combined with other purpose-designed applications.

I use digital tools and devices to better understand how people behave, but I don’t always promote them. In fact, I personally have a very old mobile phone and I don’t use much technology. Fitness tools on mobiles and smart watches are useful for increasing scientific knowledge and occasionally—only occasional—they can also be practical. When they are useful, they can be very good. Sometimes they help people to modify their behaviours.

And when you don’t use technology, what other solutions do you use?

For example, if we manage to develop a good theory about the motivation for physical activity, we can disseminate it to doctors, coaches, professionals working with people who have disabilities, etc., so that they will develop a better understanding of how they can help their patients or clients to be more active or sleep better, or whatever. There are lots of ways we can make our results known. Sometimes, it is also possible to use these digital tools only for a short period of time. Let’s say you want to improve your sleep. We will define what is adequate sleep for you and then for three months we observe how you sleep and what may be affecting you. This is known as personal science. After three months, we will stop using this tool.

A. Cabrera / ISGlobal

Is that the kind of sleep observation that is carried out in sleep clinics?

No, but the two are complementary. What you are talking about is polysomnography. That is a study method that involves monitoring sleep over a single night and recording many parameters, including brain waves, breathing, heart rate, and physical movement. It is a very accurate test, but continuous monitoring gives us a long-term perspective on the sleep patterns. Also the person being monitored is not disturbed by the presence of electrodes.

Do the results sometimes reveal that a person’s perception of how they are sleeping does not coincide with the monitoring data?

Yes, sometimes the data indicates that the person has slept well and yet she feels that she has not. This is important because psychological factors come into play. The same things happens with physical activity. Some people have the impression that they have done nothing and their smart watch shows that they have actually been moving a lot, although I have to say that it’s often the other way around! In other words, objective data has to be combined with subjective data, because they don’t necessarily say the same thing.

The fluctuating complexity of life

Did any of your findings particularly surprise you?

What surprises me is the complexity of the factors that affect our behaviours. Initially—before you have the full picture—you think you know what a person needs to change in order to find the motivation to exercise more or sleep better. At first, the task appears to be a simple one. But once you start to look at actual data, you realise that the whole process is very, very complex. And it’s not that I’m afraid of this complexity—because it is interesting from a scientific point of view and it stimulates me—but it does makes everything extremely difficult. As I said before, we’re all different and, what’s more, we all change. That’s life. Sometimes it bothers me, because I would like to define the key messages that could be easily understood but the reality is that when you look more closely, what you find is a fluctuating complexity. We can’t understand or predict anything entirely because it is all too complex. However, we can get closer to reality, to the true nature of reality.

What surprises me is the complexity of the factors that affect our behaviours. Initially—before you have the full picture—you think you know what a person needs to change in order to find the motivation to exercise more or sleep better. At first, the task appears to be a simple one. But once you start to look at actual data, you realise that the whole process is very, very complex. And it’s not that I’m afraid of this complexity—because it is interesting from a scientific point of view and it stimulates me—but it does makes everything extremely difficult.

Where do you see yourself in the future?

In my research, I would like to continue taking pleasure in what I do. Because that’s the way I feel about it now. My aim is to help ISGlobal develop a very climate-change-oriented eHealth team that investigates how personal behaviours can help mitigate climate change, but also how people can adapt to the changes. Climate change is one of the priorities the scientific community must address. While I am interested in how to improve sleep, how to prevent breast cancer and how to lead a more active life, I also have to take into account that all of that is affected by climate change and the fact that we all have a responsibility to take care of the environment.

A. Cabrera / ISGlobal

And how has ISGlobal responded to your proposals? Have you found good synergies?

Yes, lots. I couldn’t do this research if I wasn’t at ISGlobal because I’m not a climate change scientist. ISGlobal is an institution with a lot of expertise in that area.

Wouldn’t you have liked to stay in California?

I had a great time there and learned a lot, but I missed southern Europe. I feel closer to the culture here than to the American culture. This is my home!