Spending hours at a time chained to a desk is a reality for many of us. On average, adults of working age spend about nine hours a day being sedentary, engaging in activities such as desk work, watching television, and commuting. For older adults, the time spent sitting increases even further. Those aged 65 to 74 sit for around ten hours a day, while individuals aged 75 and over spend approximately eleven hours daily seated.
The dangers of a sedentary lifestyle are well publicised. Prolonged periods of sitting are detrimental to health. Extended sedentary behaviour is associated with an increased risk of premature death and various health issues, including cardiovascular disease and type 2 diabetes. This was reinforced by a recent article I came across online, reporting on research published in the British Journal of Sports Medicine in 2020 regarding sedentary behaviour and mortality.
An interesting aspect of this research is the suggestion of how much daily physical activity might offset hours of sitting. The study indicated that engaging in 30 to 40 minutes of moderate to vigorous intensity physical activity daily may counteract the negative effects of prolonged sitting. This level of activity reduces the risk of death to a level comparable with individuals who have low sedentary time. Even small amounts of exercise, or simply standing up, help improve health to some extent. Any physical activity is better than none, and beginning with short periods of movement can be beneficial.
These conclusions were based on a meta-analysis of nine studies involving over 44,000 people from four countries. The studies used objective data from fitness trackers, enhancing the reliability of the findings. These findings align with the Chief Medical Officers’ (CMOs) 2019 physical activity recommendations of at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity physical activity per week, emphasising the importance of regular exercise.
For those unable to meet the 30 to 40 minutes of activity immediately, it is encouraged to begin with shorter durations and gradually increase. The emphasis is on making incremental changes to reduce sedentary time. While current guidelines provide a general framework, more research is needed to determine precise thresholds for sedentary behaviour. The field is evolving, and future studies may offer more detailed recommendations. All physical activity counts towards improving health, and the focus is on encouraging people to be as active as possible within their capabilities. It is recognised that making universal recommendations is challenging due to differences in age, body types, and individual health conditions. Personalising activity levels may be necessary for optimal health benefits.
In addition, it is important to note that physical activity levels and sedentary behaviour are considered independent risk factors for health. This means that each one separately affects health risks, regardless of the other. In other words, prolonged sedentary behaviour (sitting or lying down for extended periods) can increase the risk of negative health outcomes even if a person engages in regular physical activity. Conversely, low levels of physical activity can elevate health risks regardless of how much or how little time is spent in sedentary pursuits.
Understanding that these are independent risk factors emphasises the need to address both separately. Simply meeting the recommended physical activity guidelines may not be enough if a large portion of the day is spent sitting. It is important to break up long periods of sitting by standing, stretching, or taking short walks. Additionally, engaging in regular moderate to vigorous physical activity is essential for health. This activity should be in addition to minimising sedentary behaviour, not seen as a replacement for it.
Therefore, to optimise health benefits and reduce risks, it is important to both decrease the amount of time spent in sedentary activities and increase overall physical activity. Addressing only one aspect may leave residual health risks associated with the other. This understanding encourages a more holistic approach to lifestyle changes, promoting both movement throughout the day and dedicated periods of exercise.
Links:
1. Nield, D. (2024) ‘Scientists calculated how much exercise we need to “offset” a day of sitting’, Science Alert, 19 September. Accessed 20 September 2024.
2. Ekelund, U., Tarp, J., Fagerland, M.W., et al. (2020) ‘Joint associations of accelerometer-measured physical activity and sedentary time with all-cause mortality: a harmonised meta-analysis in more than 44,000 middle-aged and older individuals’, British Journal of Sports Medicine, 54, pp.1499–1506.
3. British Heart Foundation (n.d.) ‘Are you sitting too much?’, British Heart Foundation. Available at: https://www.bhf.org.uk/informationsupport/heart-matters-magazine/activity/sitting-down (Accessed: 15 October 2024).
4. NHS (n.d.) ‘Why we should sit less’, NHS. Available at: https://www.nhs.uk/live-well/exercise/why-sitting-too-much-is-bad-for-us/ (Accessed: 15 October 2024).
5. Open Access Government (2019) ‘Office workers spend 75% of their waking hours sitting down’. Available at: https://www.openaccessgovernment.org/office-workers-sitting-down/71612/ (Accessed: 15 October 2024).
6. Thivel, D., Tremblay, A., Genin, P.M., Panahi, S., Rivière, D. and Duclos, M. (2018) ‘Physical activity, inactivity, and sedentary behaviors: definitions and implications in occupational health’, Frontiers in Public Health, 6, article 288.
7. González, K., Fuentes, J. and Márquez, J.L. (2017) ‘Physical inactivity, sedentary behavior and chronic diseases’, Korean Journal of Family Medicine, 38(3), pp.111–115.
8. van der Ploeg, H.P. and Hillsdon, M. (2017) ‘Is sedentary behaviour just physical inactivity by another name?’, International Journal of Behavioral Nutrition and Physical Activity, 14, article 142.
