Get off the couch!
Why is a sedentary lifestyle dangerous for health
We hear about a sedentary lifestyle throughout our lives, but hardly anyone is able to specifically explain the meaning of this term. Doctor of Medical Sciences, Professor Dmitry Medvedev told post-science what a sedentary lifestyle really is and how it harms.
How does a sedentary lifestyle differ from a sedentary one?
To begin with, it is important to understand what is the difference between a sedentary lifestyle and a sedentary one: although these two problems often occur together, they are not exactly the same thing. By a sedentary ("physically inactive") lifestyle, the World Health Organization means that a person does not comply with WHO recommendations on physical activity – that is, he gains less than 150 minutes of moderate or 75 minutes of intense aerobic exercise per week. With a sedentary lifestyle, things are somewhat more complicated.
WHO does not directly use this term, but highlights the concept of "passive pastime" (sedentary behavior, literally "sedentary behavior"). A person is considered passive when his energy consumption is less than 1.5 metabolic equivalents – that is, when he is sitting or lying down. Sleep time is not counted for the time spent passively: only those moments when a person is awake are taken into account. Examples of passive pastime include working at a computer, driving a car or sitting in front of the TV. The separation of the concepts of "inactivity" and "passive pastime" suggests that a person can simultaneously be physically active – that is, gain the recommended amount of exercise – and at the same time spend too much time sitting. For example, if a person rides a bicycle to work and back, but at the same time sits at the computer all day, almost without getting up, then the problems of passivity during the day may outweigh the benefits of cycling. If a person leads a sedentary lifestyle, most likely, at the same time he sits too much.
Despite the differences in terms, one thing is obvious to researchers: the more time a person spends sitting, the higher the risk of health problems – primarily cardiovascular diseases and metabolic disorders - therefore, WHO recommends reducing passive pastime as much as possible and getting up more often, not spending a lot of time in a row in the same position.. Additional research in the future will allow us to formulate specific recommendations on how much time you can spend passively before you need to at least get up and stretch, as well as how many hours a day you can sit without harm to your health.
How has sedentary lifestyle become a global problem?
Objective ways to quantify a person's energy consumption and compare the activity of different people have been developed by scientists quite recently. For this reason, it is almost impossible to compare exactly to what extent people's lives in the past were associated with physical exertion and how much the situation has changed, for example, in the era of the industrial revolution or with the transition to a post-industrial society. Nevertheless, based on different sources, it is possible to make an approximate estimate.
In general, until the middle – end of the XIX century, the problem of a sedentary lifestyle almost did not exist in principle: most professions were associated with hard physical labor, and a sedentary lifestyle was characteristic of a small percentage of the population. It includes not only and not so much the aristocracy – whose representatives were often physically active, for example, during military training or at balls – but sometimes artisans: in 1864, physiologist Edward Smith  studied the working conditions of London tailors and came to the conclusion that their health was much worse than people employed in agriculture, and associated this with a low level of their physical activity.
In the XIX century, books were published  prescribing certain exercises to improve posture and muscle strength – and although some doctors initially feared that intense physical exertion could overstrain the body and lead to hypertrophy of the heart, by the beginning of the XX century it became clear that in order to maintain health, it was not only possible, but also necessary to lead physically active life . Nevertheless, throughout the XX century, the number of jobs requiring intensive work was decreasing, and the number of places involving sitting in the office was increasing. In addition, new "passive" leisure activities have appeared – for example, watching TV and video games – and the development of public and personal transport has begun to encourage people to sit on their way to work or study.
In general, a lot of passivity is associated with living in cities, and a lot of activity is associated with living in rural areas, and this is confirmed by modern studies of developing countries. Thus, in Cameroon, the energy costs of rural residents are 300-600 kJ higher than the energy costs of urban residents; at the same time, urban residents have twice as much leisure time, but they mostly spend it passively . It can be assumed that similar differences were characteristic of other countries in the past – which means that as a result of the industrial revolution and urbanization, people really became more passive.
Why is it harmful to sit for a long time?
The sitting position, of course, is more convenient and energetically advantageous than the standing position: according to some data, a person spends 8-15% more energy standing than sitting. Why is sitting harmful?
First of all, prolonged sitting does not allow you to give an optimal load on the cardiovascular system, which is why it weakens, and the risk of the corresponding diseases increases. The musculoskeletal system also suffers from sitting. When a person is sitting, part of the muscles of the body does not work properly, so prolonged sitting can lead to uneven muscle development and a change in the position of the spine – which will at least cause back pain. In addition, prolonged sitting reduces the activity of bone growth factors, and ultimately increases the risk of osteoporosis.
Passive pastime also affects other body systems – for example, it contributes to the development of chronic inflammation and disrupts the work of sex hormones. In addition, sitting leads to changes in metabolism: according to a number of studies, it is associated with elevated blood glucose levels, as well as elevated levels of triglycerides, low-density lipoproteins and total cholesterol in the blood , which correlates with a high risk of various cardiovascular diseases. Finally, passivity is associated with low mood, decreased cognitive function and the development of depression.
How can you solve the problem of a sedentary lifestyle?
In the modern world, reducing sitting to a minimum is not an easy task: many inhabitants of the planet are forced to spend a lot of time at work or while studying, and it is unlikely that in such cases it is worth giving up everything and looking for a job related to physical labor. But you can try to at least change your posture more often – get up if you were sitting and stretch a little. This will allow you to put a load on the muscles that did not work before, avoid stagnation of blood and correct metabolic processes. You can also rely on the idea that you should not sit for more than one hour in a row.
Today, fitness bracelets are also very developed, which measure the pulse, assess the level of physical activity and count the calories spent during the day. Even now, such gadgets can notice that a person has been sitting motionless for too long, and send a notification with an invitation to warm up. In the future, perhaps, they will be able to give more specific recommendations – what exercises should be done and in what quantities – depending on the preferences and individual characteristics of the user.
On the other hand, the problem may lie not only in the fact that a person is forced to sit a lot at work or study, but also in the fact that movement is devoid of emotional appeal for him. He may not see the need to break away from his studies for something that he is not interested in - even if it can improve his health. Perhaps such a person simply could not find a suitable type of physical activity.
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Crichton GE, Alkerwi A. Physical activity, sedentary behavior time and lipid levels in the Observation of Cardiovascular Risk Factors in Luxembourg study. 2015
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