When I recall my childhood to share funny stories with my children, most of those memories include physical activity, playtime outdoors, sports, movement and lots of fun. Nowadays, when I go outdoors it strikes me like lightning to see not many children playing outside anymore. It freaks me out to see children with phones instead of riding their scooters and bikes or playing at the park. When did we change that much?
As we get more dependent on technology, we seem to decrease the time we spend socializing and exercising. Of course, this behaviour has consequences, and we can only change our future and the future of those children if we first understand what we are doing wrong and then we decide to do something about it. To begin with, let’s define two concepts: Physical activity and sedentary behaviour.
Physical activity is any activity that gets your body moving, makes your breathing become quicker and your heart beat faster (1) You can be physically active in many different ways, at any time of day. You can walk to the shops or run a little bit to catch the bus. You can ride a bike to work or play sports. Everything counts!
On the contrary, sedentary behaviour consists on sitting or lying down (except for when you are sleeping) for large amounts of time, for example, we can be sedentary when at work, when travelling and commuting or during leisure time. This kind of behaviour requires a minimal amount of energy to perform, so generally speaking, it does not contribute directly to increase our heartbeat and physical wellbeing. Some other examples are: television viewing, computer and electronic games use, sitting while reading, talking on the phone, socialising, relaxing or resting and listening to music (2)
Sedentary behaviour (too much sitting) may be a deeply-embedded public health problem, which is additional to lack of physical activity (too little exercise) (3)
And, why is this so important?
Primarily, because physical inactivity is the second greatest contributor, behind tobacco smoking, to the cancer burden in Australia (4) (5) Physiologically speaking, this could be explained by the lack of contractions by postural muscles (predominantly those of the lower limbs) while sitting, which in an active person, are continually contracting to keep the body upright and to prevent loss of balance (3)
In studies with animals, this lack of contractions suppresses the skeletal muscle lipoprotein lipase which is important for breaking blood fats and triglycerides, and also, reduce the break down and use of glucose, elevating its levels in the blood (3) High triglycerides, high blood glucose, this doesn’t sound good, right? The decline in the lipoprotein lipase activity does not appear to exist when light incidental activity (including standing) is introduced. However, there is a need to replicate these animal studies in human, so interpretation of this results needs to be done with caution.
What else might explain Sedentary Behaviour associations with health?
Easy-peasy! When we are laying down in the couch (aka couch potato), watching TV or reading, the energy intake increases, because we tend to eat more when distracted, and also because we tend to snack and crave for junk food when having fun with friends. Therefore, energy expenditure associated with physical activity is almost none, and no caloric deficit is present. The more we eat and the less we move, the more weight we gain! Did you know that sedentary behaviour is also associated with depression?
Ok Lilia, convince me: What are the benefits?
There are so many benefits associated with being active that we really need to get into action. Moving more and sitting less will:
- Reduce your risk of, or help manage, cardiovascular disease and type 2 diabetes.
- Maintain or improve your blood pressure, cholesterol and blood sugar levels.
- Reduce your risk of some cancers.
- Help prevent unhealthy weight gain and assist with weight loss, while helping you to develop and maintain overall physical and mental well-being.
- Build strong muscles and bones.
- Create opportunities for socializing and help you prevent and manage mental health problems (1).
So, can you be highly sedentary but also active?
Let’s use Homer Simpson as an example: Imagine Homer, waking up and driving his pink car to work for about 15-30 minutes. After spending 8 hours working at the office, he decides to run a little bit before heading home. Usually, Homer runs for 30 minutes at moderate intensity, 5 days a week and after doing so, he drives back home, to have dinner with his family and watch TV before going to bed.
So, let’s see. If you remember my previous article about Physical Activity Guidelines: Are you on the right track? you should know that the recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness and flexibility in healthy adults is just 150 minutes of moderate to vigorous intensity exercise, at least 5 days a week. Is Homer Simpson active? YES because he complies with the 150 minutes specified in the guidelines. Is Homer highly sedentary? also YES as he spends more than 9 hours performing low-intensity activities.
In consequence, sedentary behaviour is NOT equivalent to physical inactivity. That is why the Australian Physical activity guidelines now include a set of sedentary behaviour guidelines and it doesn’t refer only to physical inactivity.
Being physically active and limiting your sedentary behaviour every day is essential for your health and well-being. You can achieve this by minimising the amount of time spent in prolonged sitting or by breaking up long periods of sitting as often as possible. Trying to achieve a minimum of 250 steps every hour is a good way to start. Electronic devices can always help to pursue this with hourly reminders.
Let’s get moving!
- Australia’s Physical Activity and Sedentary Behaviour Guidelines: Adults (18-64 years). [Internet]. 2014 [cited 2019 Jan 17] Available from: http://www.health.gov.au/internet/main/publishing.nsf/Content/health-pubhlth-strateg-phys-act-guidelines
- Ainsworth BE, et al (2000) Compendium of physical activities: an update of activity codes and MET intensities, Med Sci Sports Exerc. 32(9 Suppl): S498-504.
- Healy, G. (2012) ‘The Unique Influence of Sedentary Behaviour on Health’ in Physical activity and Public Health Practice, Eds. Ainsworth & Macera, Taylor & Francis Group. [Internet]. 2012 [cited 2019 Jan 17] Available from: https://bit.ly/2VYIQoQ
- More than half of all Australian adults are not active enough. Source: Australian Bureau of Statistics (ABS) 2013. Australian Health Survey: Physical Activity, 2011-12. ABS Cat. No. 4364.0.55.004. Canberra: ABS.
- Global Health Risks: Mortality and burden of disease attributable to selected major risks. World Health Organization, 2009.
Lilia has a Bachelor degree in Nutrition and Dietetics and a Post Graduate Diploma in Sports Nutrition; passionate about Sports Nutrition, performance enhancement, exercise science and weight management. Lilia always works toward the fulfilment of her client goals, prioritizing their health over nutrition trends.