These are the results of a survey conducted by Turid Skrede in connection with her doctoral thesis at the Norwegian School of Sport Sciences (NIH). She wanted to find out how respective sitting still and physical activity among young people affects the risk of contracting cardiovascular diseases. Consequently she has studied almost 1,200 class 5 pupils from 57 different schools in the county of Sogn and Fjordane.
Need to be active
Professor Skrede’s measurements were carried out during the autumn and spring of the 2014/15 academic year. All the children wore activity monitors for a whole week. Measurements were also made of their height, weight and a number of risk factors associated with developing serious illnesses.
Professor Skrede then compared their activities and physical fitness with the following risk factors: large waistline, body mass index, high blood pressure, poor cholesterol and insulin levels. And she discovered that:
- Sitting still, even for a long time, is not as bad as previously thought
- The important thing is engaging in moderate to high intensity physical activity
- People do not become overweight by sitting still, but those who are overweight often spend too much time sitting still
- Children with poor physical fitness benefit most health-wise from being more physically active
—So sitting still is not actually a bad thing?
—Well there has been quite a lot of scaremongering about this. Professor Skrede points out that previous studies have often used TV and screen viewing time for measuring time spent sitting still. In these cases the results are affected by what one actually does while sitting still, e.g. snacking and drinking fizzy drinks. These studies have not included any activities carried out during the remainder of the day.
—Using our objective goals, we found no connection between sitting still and health, but the more activity one does, the better.
Support for sitting
—Is this partly a self-contradiction?
—Well yes, we probably need to focus more on the fact that children should be physically active, rather than that they should spend less time sitting down. To put it simply: you could allow pupils to relax during one of their breaks, as long as they engage in far more strenuous activities during their other ones, explains Professor Skrede. —There is no point in replacing sitting down with gentle activities. If you are going to be active, then you need to feel your heart beating fast.
According to the World Health Organisation (WHO) cardiovascular diseases kill almost 18 million people each year and result in premature death for many others. Even though these diseases mainly affect adults, they can start developing during one’s childhood years. Physical inactivity is one of the primary causes. Consequently both the WHO and the Norwegian Directorate of Health recommend a minimum of 30 minutes of moderate to high intensity activity per day for adults and 60 minutes for children and young people. “Moderate” to “high” means activities ranging from fast walking to more active pursuits.
—However, if adults spend 8-9 hours a day sitting down, they also need to be active for one hour per day. Otherwise too much sitting down is not a good thing. So it is the absence of proper activity which is critical. It is therefore disturbing that so many adults and children are not active enough.
Don’t get bigger
Professor also discovered that physical activity does not have any particular impact on the composition of the body, even if one spends a lot of time sitting still. However, those who put on weight become less active. This quickly develops into a vicious circle, which is also linked to diet - although Professor Skrede did not address this in her thesis.
—However, it does say something about how important it is to prevent children from putting on weight: if they first become overweight, they will be dogged by problems which can follow them into adulthood. Everyone benefits from being more active, especially people who are not very fit.
—They will have lower blood pressure and a healthier bodily composition, while their cholesterol and insulin levels will be much better regulated, regardless of how fit or overweight they are. This is all decisive for reducing the risk of contracting cardiovascular diseases, which was the aim right from the start of the study.
Turid Skrede will be defending her doctoral thesis, «Prospective associations between sedentary time, physical activity and cardiometabolic risk factors in children: The Active Smarter Kids Study» at the Norwegian School of Sport Sciences on 5 April 2019.
Professor Skrede works on a daily basis as a college lecturer at the Western Norway University of Applied Sciences in Sogndal.