Researchers at the University of So Paulo’s Medical School (FM-USP), Brazil now have an “encyclopedia” in the form of a 100-page review of the literature that took three years to produce, compiling information about the effects of long periods of sitting on the organism and human health, as well as concepts, definitions and recommendations.
Sedentary behavior is now ubiquitous in many walks of life and a risk factor for so many health problems that scientists are increasingly studying its effects.
The article reinforces the message “Sit less, move more” while pointing to gaps in clinical trials and experimental studies that need to be filled in order to elucidate more fully the physiological effects of combining exercise with interruptions in being seated.
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Even people who exercise moderately for some time but sit or lie for the rest of their waking hours run a greater risk of developing heart and vascular problems, for example. Energy expenditure is very low under these conditions.
According to the researchers, long-term interventions aimed at reducing or interrupting sedentary behavior with light to moderate physical activity tend to lead to negligible benefits in terms of body weight, waist circumference, percent body fat, fasting glucose, insulin levels, and vascular function in adults and the elderly. However, these practices can serve as a springboard to increase physical activity for people with difficulties in achieving exercise targets, such as the overweight and obese.
Embrace Fitness & Movement Not Sedentary Lifestyle
Some studies show that the ideal could be at least 8,000 steps per day to reduce the risk of premature death from avoidable disease, although recent findings suggest about 7,000 steps already produce a considerable reduction in the probability of premature death. The intensity of physical activity may vary from light (such as walking while shopping) to moderate (leading to a rise in heart and breathing rates) to vigorous (leading to exhaustion).
About 1 billion people will be living with obesity by 2030, according to the World Obesity Atlas, produced by the World Obesity Federation, which in its own words has over 65 national and regional member organizations and the mission to lead and drive global efforts to reduce, prevent and treat obesity.
Data for 2021 analyzed by the Ministry of Health’s Vigitel survey (Vigilncia de Fatores de Risco e Proteo para Doenas Crnicas por Inqurito Telefnico, “Surveillance of Risk Factors and Protection for Chronic Diseases by Telephone Interview”) show that 22% of adult Brazilians are obese based on body mass index (BMI).
BMI is calculated by dividing weight by height squared, with 25-30 being considered overweight (57% of adult Brazilians) and over 30 as obese.
Obesity heightens the risk of other disorders, such as heart disease, diabetes, high blood pressure, liver disease, several types of cancer (especially colorectal and breast cancer), kidney problems, asthma, and severe COVID-19.
Significance of Physical Activity To Address Sedentary Lifestyle
Another gap in the literature evidenced by the study, according to the authors of the review article, related to the limitations of the experimental models used by researchers in the field, hindering comprehension of the physiology of sedentary behavior. These models include bed rest, immobilization, reduced step count, and reducing or interrupting prolonged sedentary behavior.
“These are the most widely used models, and they have serious limitations. When you study the physiology of a healthy person who is bedridden or has to wear an immobilizing cast for a month, for example, you must bear in mind that this isn’t what happens in ordinary everyday life, where people normally alternate between sedentary periods and a certain amount of physical activity, which may well be very light,” Gualano said.
This point is important because most of the studies analyzed in the review involved healthy people who did not display altered risk factors. More significant effects of sedentary behavior interruption might have been observed in subjects who were not healthy. Moreover, the evidence on the adverse effects of sedentary behavior applies mainly to young adults and older people, as few studies involving children and adolescents are available.
The article compiles all the relevant physiological evidence, from body weight, energy balance, and intermediate metabolism to cardiovascular, respiratory, skeletomuscular, and nervous systems, as well as the immune system and inflammatory response.
It concludes that energy expenditure, heart rate, skeletomuscular blood flow, and contractile activity are all higher when a person is sitting than reclining but lower than when standing or during physical activity of any intensity.
Reference :
- Physiology of sedentary behavior – (https://journals.physiology.org/doi/abs/10.1152/physrev.00022.2022)
Source: Eurekalert
