How does prolonged sitting contribute to cardiovascular disease risk?
Prolonged sitting is associated with increased risks for subclinical atherosclerosis and cardiovascular disease development, and this is thought to be partially due to sitting-induced disturbances in macro- and microvascular function as well as molecular imbalances 1. The physiological response to a single bout of sitting includes acute lower-extremity endothelial dysfunction, blood pooling in the lower extremities, reduced venous return, decreased stroke volume, and a subsequent decrease in lower extremity blood flow 2. Additionally, prolonged sitting causes a decrease in shear stress, leading to a decrease in endothelial cell health and a decrease in stroke volume, triggering the autonomic nervous system to increase heart rate in an attempt to maintain cardiac output while vasoconstricting resistance vessels to maintain blood pressure 2. Interrupting prolonged sitting may help to protect the cardiovascular system, potentially reducing the burden of blood pooling and stimulating cardio-autonomic activity 2. A simulated workday of prolonged sitting increased seated blood pressure and pulse wave velocity, adding to the evidence suggesting a deleterious effect of prolonged sitting on cardiovascular health 3.
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Background Information:
The effects of acute prolonged sitting on heart rate variability and heart rate were investigated in a meta-analysis, which found that interrupting prolonged sitting yielded a small non-significant increase in heart rate, potentially indicative of increased metabolic demand 1. Additionally, a scoping review focused on sedentary behavior during the COVID-19 lockdown and its impact on chronic disease risk, highlighting the adverse effects of prolonged homestay on cardiovascular disease risk, obesity, hypertension, cancer, and mental health illness 2. Furthermore, a study on disrupting prolonged sitting in active young adults found that short bouts of exercise significantly reduce swelling in the lower leg and IL-8 levels in the saliva, indicating the potential benefits of disrupting prolonged sitting to reduce inflammation 3.
Current Research and Developments:
The meta-analysis on acute prolonged sitting revealed that interrupting prolonged sitting with walking increased heart rate, while standing or other interruption modalities had trivial-small, non-significant effects 1. The scoping review emphasized the adverse effects of sedentary behavior, especially prolonged sitting, on chronic diseases such as obesity, cardiovascular disease, cancer, and mental health disorders 2. Additionally, the study on disrupting prolonged sitting in active young adults demonstrated that short bouts of exercise significantly reduce swelling in the lower leg and IL-8 levels in the saliva, indicating the potential benefits of disrupting prolonged sitting to reduce inflammation 3.
Practical Applications:
The research on sedentary behavior during the COVID-19 lockdown highlighted the importance of breaking sitting and engaging in physical activity to reverse the adverse effects associated with excessive sitting 2. Furthermore, the study on disrupting prolonged sitting in active young adults suggested that even among healthy, active, young adults, disrupting prolonged sitting can significantly reduce swelling and systemic inflammation, indicating the practical applications of disrupting prolonged sitting to reduce inflammation and swelling 3.
Conclusion:
The blog post discussed the effects of acute prolonged sitting on heart rate variability and heart rate, the impact of sedentary behavior during the COVID-19 lockdown, and the potential benefits of disrupting prolonged sitting to reduce inflammation and swelling. It is evident that sedentary behavior, particularly prolonged sitting, has significant implications for cardiovascular health and overall well-being. The research findings emphasize the importance of breaking sitting and engaging in physical activity to mitigate the adverse effects of sedentary behavior. Future research should focus on optimizing interruption strategies and confirming the vascular benefits of physical activity breaks during prolonged sitting 1, 2, 3.
