For this we need to know the average amount of sedentary behaviour when it is measured in different ways:
Harvey JA, Chastin SFM, Skelton JA, 2014. How Sedentary are Older People A Systematic Review of the Amount of Sedentary Behavior. Journal of Aging & Physical Activity, 2014 Nov 11. [Epub ahead of print]
To answer this we need to consider the PREVALENCE of sedentary behaviour:
Harvey, Juliet A.; Chastin, Sebastien F.M.; Skelton, Dawn A. 2013. “Prevalence of Sedentary Behavior in Older Adults: A Systematic Review.” Int. J. Environ. Res. Public Health 10, no. 12: 6645-6661.
Broadly measurement of sedentary behaviour is either carried out objectively by accelerometry or subjectively by self-report. Whether objectively or subjectively measured, the time frame of measurement of sedentary behaviour is defined by minutes, or hours, in a week, or day, or set period time. Papers may present data as an average or percentage and may provide total sedentary time or patterns of sedentary behaviour accumulation.
With subjective reports different domains of sedentary behaviour are considered. Study participants are often asked about total sitting time in the day, which may be the waking day, in 24hrours or between specific time frames. Alternatively, the participants may be asked about particular activities from which sedentary behaviour can be inferred by asking about the following:
- TV viewing
- Computer Use/Video Games
- Screen Time
- Telephone Use
- Sitting Socializing with Friends
- Listening to Music
The recall period across studies varies from considering the previous day to the last month, or people may be asked to consider a “typical” or “average” day. The information retrieval method of the questionnaires may be postal, telephone administered or face-to-face. Large scale surveys include questions about sedentary behaviour, such as: The Scottish Health Survey; The Australian Diabetes and Lifestyle Study; International Physical Activity Questionnaire (IPAQ short & long forms); Time Use Study; National Health and Nutrition Examination Survey; European Prospective Investigation into Cancer; Behavioral Risk Factor and many more! Sedentary behaviour questionnaire are also used in smaller scale trials.
Sedentary behaviour can also be objectively measured by use of activity monitors, such as, ActivCal & ActiGraph, where counts of <100/min are considered sedentary; or the ActivPAL which measures time by posture. The definition of what constitutes a “valid wear day” and how many valid days are required for inclusion in data sets changes from on study to the next. For example, to be included a study might require at least 4 days/7 day wear with a valid day being at least 10 hours of recording.
Activity monitor can be combined with other methods eg with interviews or body worn camera to help define the context of sedentary behaviour. This can be done with the participant or inferred in the absence of the participant. When this is done with the participant this proves to be a rich source of information on participants behavioral choices.
Sedentary behaviour is defined as a sitting or lying posture where little energy is expended (SBRN, 2012). Over 4 hour of sedentary behaviour has been defined as a level that is sufficiently sedentary to cause health and wellbeing concerns in the older population (Dogra and Stathokostas, 2012). Whether measurements are subjective or objective, the majority of older adults are sedentary. Almost 60% of older adults reported sitting for more than 4 hours per day, when objectively measured it is found that 67% of the population are sedentary for more than 8.5 hours in their waking day (Harvey et al., 2013). When looking at specific activities carried out in a sitting or lying posture, 65% of older adults sit in front of a screen for more than 3 hours daily and over 55% report watching more than 2 hours of TV (Harvey et al., 2013).
Sedentary Behaviour Research Network. Letter to the editor: Standardized use of the terms “sedentary” and “sedentary behaviours”. Appl. Physiol. Nutr. Metab. 2012, 37, 540–542.
Dogra S, Stathokostas L. Sedentary behavior and physical activity are independent predictors of successful aging in middle-aged and older adults. J. Aging Res. 2012,doi:10.1155/2012/190654.
Harvey JA, Chastin SC, Skelton DA. Prevalence of Sedentary Behavior in Older Adults: A Systematic Review. Int J Environ Res Public Health 2013, 10, 6645-6661.
For further information on the prevalence of sedentary behaviour please see:
Physical activity and aging, with a focus on falls, was the order of the enjoyable and highly informative evening of Prof. Dawn Skelton’s inaugural lecture at Glasgow Caledonian University. In Prof Skelton’s career she has made a massive contribution to her field and it was wonderful to see how her work has evolved from initial lab work into in integration into normal clinical practice, truly inspirational!
Therefore, the evening is difficult to sum up in a short blog! I think the main message is you are never too old, or too young, to start reducing sedentary behaviour and increasing physical activity in order to have a happier, healthier older age. To achieve this we are ideally looking to meet the guidelines of 150mins of moderate intensity physical activity per week made up of bouts of activity of at least 10mins, along with strength training and balance training on 2 days of the week…. And reducing sitting time!! Of course, it was also an honour to have our work cited in Prof. Skelton’s lecture (http://www.mdpi.com/1660-4601/10/12/6645).
- 59% of older adult’s report sitting for more than 4 h per day
- 67% of the older population are found to be sedentary for more than 8.5 h daily when objectively measured