Sedentary behavior or insufficient physical activity can negatively impact an individual’s physical and mental health. It can potentially increase the risk of many non-communicable diseases, including cardiometabolic disorders.
The global prevalence of physical inactivity was estimated to be 27.5% in 2016, with women showing higher sedentary behaviors than men. Moreover, the majority in 2016 was 2-times higher in high-income countries than in low-income countries.
The World Health Organization (WHO) has developed a Global Action Plan on Physical Activity 2018-2030 (GAPPA) to help countries increase physical activity at the population level by developing and introducing national policies to ensure appropriate roads for cycling and walking. The plan is to achieve a 15% reduction in the global prevalence of physical inactivity by 2030.
Sedentary epidemic
Physical inactivity has become the fourth leading risk factor of mortality. People with sedentary behaviors have 20-30% higher risk of all-cause mortality than those who almost regularly practice moderate-intensity physical activities.
Globally, physical inactivity is associated with 3.2 million deaths and 32 million disabilities per year.
Sitting and smoking: A comparative analysis
Prolonged sitting has many adverse health effects, including obesity, type 2 diabetes, abnormal blood lipid profile, and hypertension (high blood pressure). These health outcomes collectively can increase the risk of metabolic syndrome. Moreover, prolonged sitting can significantly increase the risk of cardiovascular disease- and cancer-related mortality.
Researchers have analyzed a total of 13 publications and found that sitting for more than eight hours without any physical activity is associated with a mortality risk comparable to that caused by obesity and smoking. This analysis, which includes more than one million people, has also pointed out that moderate-intensity physical activity for 60 to 75 minutes a day can mitigate the negative health effects of prolonged sitting.
Health consequences of sitting
The human cardiovascular and digestive systems function more efficiently when the body is upright. Moreover, a physically active lifestyle helps maintain the optimal balance between energy consumption and expenditure.
In contrast, prolonged sitting in a place restricts calorie burning, subsequently increasing excess calorie accumulation and fat deposition in the body. All these factors can collectively increase the risk of developing obesity, type 2 diabetes, and metabolic syndrome.
Prolonged sitting has been found to increase the risk of all-cause and cardiovascular disease-related mortality. A study comparing different sitting durations has shown that people who spend more than four hours sitting in front of television have a 50% higher risk of all-cause mortality than those who sit for less than two hours.
Similarly, another study has reported that people who sit for more than 23 hours a week have 64% higher risk of cardiovascular disease-related mortality than those who sit for less than 11 hours a week.
Evidence also indicates that prolonged sitting can negatively impact mental health and increase the risk of developing dementia and anxiety. An Australian study has found that employees who sit for more than six hours a day have a higher risk of developing anxiety and depression than those who sit for less than three hours a day. This risk is higher among female employees.
Prolonged physical inactivity can negatively impact mental health through various causes, including sleep disturbance due to prolonged screen time, poor physical health due to inactivity, and social isolation.
These observations draw attention to the positive impact of exercise and physical activity on mental wellbeing.
Researchers have also linked sedentary behaviors with cognitive decline. Physical inactivity is associated with reduced medial temporal lobe thickness in middle-aged and older adults. This brain area is responsible for memory formation and storage. A thinner medial temporal lobe can increase the risk of dementia and Alzheimer’s disease.
Prolonged sitting is believed to be associated with an increased risk of certain cancers, including breast, colorectal, lung, prostate, endometrial, and ovarian cancers. Although it is still unclear how sitting increases cancer risk, studies have found increased levels of certain cancer biomarkers, such as C-reactive protein, in individuals who sit for a prolonged time.
Prolonged sitting has been linked to neck and back pain. Researchers have found that sitting exerts significantly more pressure on the back than standing. This could lead to back pain. Similarly, looking down at screens for a prolonged time while sitting can lead to postural kyphosis, which can cause neck and back pain and fatigue.
Prolonged sitting can increase the risk of varicose veins by pooling down more blood in the legs. In some cases, blood clots can form in leg veins (deep vein thrombosis), which can eventually break off and translocate to other body parts, including the lungs (pulmonary embolism).
Promoting an active lifestyle
The detrimental health effects of prolonged sitting can be avoided by promoting an active lifestyle. Evidence indicates that taking work breaks after 30 minutes of continuous sitting can reduce mortality risks. Body movements at frequent intervals are more beneficial than a 45-minute workout once a day.
Switching body positions from sitting to standing every 20 to 30 minutes could be beneficial. A 50:50 ratio for sitting to standing is generally advised to start with. Working desks that can be adjusted at various levels could be useful. Sitting on a medicine ball instead of a chair could also be beneficial.
A specialized treadmill desk or under-desk treadmill could be useful for keeping the body in motion while working.
It is also important to stay active at home. While watching television, body movements can be restored by getting up and walking around during commercials or between episodes. Standing or walking while talking on the phone is another easy way to stay active.
Incorporating light physical activities, such as hip and lower body stretching, yoga, and flexibility training, in the daily routine could be immensely helpful for physical and mental wellbeing.
