The Risks of Prolonged Sitting

Prolonged sitting has emerged as a significant public health concern, with evidence linking it to various adverse health outcomes across all age groups. This sedentary behaviour, prevalent in modern workplaces, schools, and lifestyles, poses risks that extend beyond the lack of physical activity.

So what areas could it affect?

Let’s start with the HEART.

In adults, prolonged sitting has been associated with an increased risk of cardiovascular disease. A systematic review found that sedentary time, independent of physical activity levels, is linked to a higher risk of cardiovascular disease, type 2 diabetes, and all-cause mortality. The mechanisms behind this association may involve changes in metabolic function and vascular health.

Alarmingly, these effects are not limited to adults. A study on young girls aged 7-10 years found that a 3-hour period of uninterrupted sitting caused a 33% reduction in vascular function. This highlights the acute negative effects of prolonged sitting even in children, potentially setting the stage for future cardiovascular issues.

What was that about Metabolic Dysfunction?

Sitting for extended periods can negatively impact metabolic health across the lifespan. In adults, studies have shown that prolonged sitting is associated with increased insulin resistance, potentially leading to the development of type 2 diabetes. Additionally, sedentary behaviour has been linked to unfavourable changes in lipid profiles, including elevated triglycerides and decreased HDL cholesterol levels.

In the paediatric population, sedentary behaviour is linked to increased cardiometabolic risk independent of physical activity levels. Childhood obesity, often associated with excessive sitting, is linked to increased risk of adult obesity, certain cancers, and cardiometabolic morbidity later in life.

Wait on – did you say certain cancers??

Yep.

Emerging evidence suggests a potential link between prolonged sitting and certain types of cancer in adults. A meta-analysis found that sedentary behaviour was associated with an increased risk of colon, breast, and endometrial cancers. While the exact mechanisms are not fully understood, it is thought that changes in metabolic function and prolonged, excessive inflammation may play a role.

And that inflammation? It’s not limited to the body. Inflammation can have an impact on our brain function as well – and this is shown with prolonged sitting too! Studies have indicated that excessive sedentary time may be associated with an increased risk of depression and anxiety in adults. In children, sedentary behaviour is associated with increased risk of anxiety and more negative affect (more time feeling unhappy or sad). In teenagers, this seems to work in a slightly different way in that it reduces the amount of time with a positive affect (feeling of happiness or joy).

But then what about the MUSCULOSKELETAL SYSTEM?

In a surprise to no one, research has demonstrated an association between occupational sitting and an increased risk of low back pain. Furthermore, extended periods of sitting can lead to poor posture, muscle weakness, and reduced flexibility, contributing to neck and shoulder pain. Fun times.

So what do we do?

Well, research has shown that breaking up prolonged sitting periods with short bouts of activity can have beneficial effects on metabolic health in both adults and children. Even brief interruptions in sedentary time have been associated with improvements in glucose metabolism and other cardiometabolic risk factors.

For kids we can look at:

1. Changing the amount of screen time: In Australia it is not recommended for 1-year-olds, and no more than 1 hour for 2-5 year-olds (less is better).

2. Increasing the amount of physical activity: At least 180 minutes daily for children 1-4 years old, with at least 60 minutes being moderate to vigorous intensity for 3-4 year-olds.

So really, the health risks associated with prolonged sitting are multifaceted and significant across all age groups. From cardiovascular disease and metabolic dysfunction to musculoskeletal issues and increased mortality risk in adults, or vascular function impairment to obesity and mental health issues in children, the evidence points to the importance of reducing sedentary time. While regular physical activity is crucial, it may not fully counteract the risks associated with excessive sitting. Strategies to reduce and break up sedentary time in work, schools and homes are essential for promoting public health in our increasingly sedentary society. This is particularly important for children, as habits formed in our childhood can have lasting impacts on our health throughout our lives.

Some Useful Reading:

• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5618737/
• https://www.betterhealth.vic.gov.au/health/healthyliving/the-dangers-of-sitting
• https://www.bmj.com/content/350/bmj.h306
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3404815/
• https://www.mayoclinic.org/healthy-lifestyle/adult-health/expert-answers/sitting/faq-20058005
• https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-021-10893-8
• https://journals.sagepub.com/doi/full/10.1177/2165079917737558
• https://www.ajpmonline.org/article/S0749-3797%2810%2900413-7/fulltext
• https://pubmed.ncbi.nlm.nih.gov/26370881/
• https://www.betterhealth.vic.gov.au/health/healthyliving/the-dangers-of-sitting
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7785062/
• https://www.bmj.com/content/350/bmj.h306
• [https://www.nhs.uk/live-well/exercise/why-sitting-too-much-is-bad-for-us/
• https://www.mayoclinic.org/healthy-lifestyle/adult-health/expert-answers/sitting/faq-20058005
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3404815/
• https://www.who.int/news/item/24-04-2019-to-grow-up-healthy-children-need-to-sit-less-and-play-more