Sedentary behavior, defined as activities that require minimal to no body movement, which consequently result in low energy expenditure, has emerged recently as a potential indicator of both physical and mental health in adult populations. There is an association between sedentary behavior and mental health issues including depression, anxiety, and self-esteem.

What is a sedentary lifestyle?

Sedentary behavior is defined by the Sedentary Behaviour Research network in 2012 as any conscious behavior such as leaning or sitting which results in an energy expenditure of 1.5 metabolic equivalent task (MET) or less. MET is defined as the work metabolic rate relative to the standard resting metabolic rate (RMR) of kcal/(kg/h). One MET is the RMR for a person at rest.

To express quantitative MET values qualitative:

• Sedentary behaviour: 1.0–1.5 METs (
• Light intensity is 1.6–2.9 METs
• Moderate intensity is 3–5.9
• Vigorous intensity is ≥6 METs

Physical activity and its implications on mental health

Strong evidence suggests that physical activity is an effective strategy in reducing anxiety, depression, and negative mood. This has been found by reviews and randomized controlled trials alike.

A study conducted in Australia reported increased rates of depression, anxiety, and stress symptoms associated with changes in physical activity. In the context of the COVID-19 pandemic, a study from America reported that reduced physical activity combined with increased screen time from both pre and post COVID19 shutdown increased the likelihood of depression, loneliness, and stress.

Another report demonstrated a positive effect of light activity on mental health. This finding was corroborated by a UK survey which demonstrated that negative mental health outcomes, including anxiety, were negatively associated with moderate daily physical activity.

Sedentary behavior and depression

Mentally passive sedentary behaviors which encompass sitting, listening to media, television viewing, and talking, are positively correlated with depression risk. Contrastingly, mentally active sedentary behaviors such as reading, typing and participation in a meeting are not always associated with depression risk.

In particular, the use of a computer, classed as a mentally active sedentary behavior was found not to be correlated in one study with depression, but in another demonstrated positive correlation with depression risk. This study demonstrates its controversial association with depression.

The mechanistic basis that underpins the correlation between sedentary behavior and depression is thought to include the blocking of direct communication and reduction in social interactions, or the reduction in available time to engage in physical activity which is known to increase overall sense of wellbeing and reduce risk of depression.

Sedentary behavior and cognitive function

There is a controversial relationship between sedentary behavior and cognitive function. Some studies have indicated that a less sedentary lifestyle and less sedentary work patterns have beneficial cognitive effects, while others have demonstrated no changes in cognitive function.

A study that looked at replacing sedentary time slots with other forms of activity across six months in elderly adults exhibiting little physical activity significantly improved cognitive functions. These activities included moderate-to-vigorous physical activity and sleep. Contrastingly, low-intensity physical activity did not cause statistically significant changes.

Effects of COVID-19: Sedentism and wellbeing outcomes

A recent study conducted in the United Kingdom in response to COVID-19 investigated the association between physical activity and sitting time on adults' mental health as well as the influence of potential mediators and confounding variables. The researchers conducted an online survey between May and June 2020. 284 participants self-reported physical exercise, sitting time and mental health, through validated questionnaires. Results demonstrated that sitting time was strongly associated with adverse mental health effects during lockdown conditions.

Interestingly, those with lower sitting times showed a significantly lower depression score than those that demonstrated increased physical activity. Similarly, subjective wellbeing appeared to be more strongly influenced by a reduction in total sitting time, with physical activity being non-significant in comparison. A combined analysis demonstrated that increased well-being was found to be the greatest in a group with the lowest sitting time and moderate or high physical activity compared to those that had high sitting time and low physical activity (that is, the reference group).

Although the association between depression and sedentary behavior is well established in the literature, there is less robust, and indeed a controversial association between sedentary behavior and wellbeing.

In addition, though there is a strong association between mental health and sedentary behavior, no studies have yet investigated the moderation effect of physical activity on the impact of sedentary behavior on the outcomes for mental health. Some evidence suggests that higher volumes of physical activity, that is between 60 and 75 minutes per day, can protect against an increased risk of mortality as a consequence of prolonged sitting (that is, more than 8 hours per day). However, this buffering effect for other mental health outcomes i.e. wellbeing is less demonstrable.

In addition, the study performed a sub-group analysis that demonstrated the relationship between different aspects of physical activity and mental health. Consequently, domestic and garden physical activity as well as leisure-related physical activity showed a negative association with depression and a positive association with well-being. In a study conducted in Italy, gardening demonstrated a positive impact on psychological distress.

The impact of socio-demographic factors, sedentary behavior, and well being

A study conducted during the pandemic demonstrated that sociodemographic predictors for mental health conditions such as depression and anxiety included female gender and young age, with university students having higher rates of depression relative to the overall population and women being more than two times as likely to suffer from depression about men.

This increased risk persists until the mid-50s. In addition to gender and age, those who are of lower income, or possess one or more comorbid health conditions find a previous diagnosis of mental health increases one’s risk of poor wellbeing as a result of sedentary behavior.

References

• Pears M, Kola-Palmer S, De Azevedo LB. (2021) The impact of sitting time and physical activity on mental health during COVID-19 lockdown. Sport Sci Health. doi: 10.1007/s11332-021-00791-2.
• Park JH, Moon JH, Kim HJ, et al. (2020). Sedentary Lifestyle: Overview of Updated Evidence of Potential Health Risks. Korean J Fam Med. doi:10.4082/kjfm.20.0165.
• Hamer M, Coombs N, Stamatakis E (2014) Associations between objectively assessed and self-reported sedentary time with mental health in adults: an analysis of data from the Health Survey for England. BMJ Open. doi: 10.1136/bmjopen-2013-004580.
• Teychenne M, Costigan SA, Parker K. (2015) The association between sedentary behaviour and risk of anxiety: a systematic review. BMC Public Health.; doi:10.1186/s12889-015-1843-x.
• Hamer M, Coombs N, Stamatakis E. (2014) Associations between objectively assessed and self-reported sedentary time with mental health in adults: an analysis of data from the Health Survey for England. BMJ Open. doi:10.1136/bmjopen-2013-004580.

Further Reading

• All Exercise Content
• Where did 10,000 steps a day come from?
• Is it Safe to Exercise During Pregnancy?
• Why You Should Exercise in the Morning
• Wearable Fitness Trackers

Written by

Hidaya Aliouche

Hidaya is a science communications enthusiast who has recently graduated and is embarking on a career in the science and medical copywriting. She has a B.Sc. in Biochemistry from The University of Manchester. She is passionate about writing and is particularly interested in microbiology, immunology, and biochemistry.