In 1713, Italian physician Bernardino Ramazzini observed that tailors and cobblers (shoe repairmen) who sat at their work most of the time and were called "chair workers" as a result, tended to show greater health problems compared to those whose work involved more movement and physical activity. Fast forward to 1953. A study is published that follows bus drivers and conductors in London. The study finds that the bus drivers, who are seated 90% of the time, show far greater rates of cardiovascular disease (CVD) compared to the conductors, whose work involves them standing and moving up and downstairs in the famous double-decker London buses. A year later (1954) another study appears in the journal Lancet showing that being seated for extended times, such as on a long flight, greatly increases the chances of being afflicted with a serious medical condition called deep-vein thrombosis (DVT), characterized by having a blood clot form in the legs. In a worst-case scenario, this newly formed clot or thrombus can travel in the blood to the lungs, producing a pulmonary embolism that could easily prove fatal. As a point of interest, those who inject "site enhancing" drugs, such as Synthol and similar products, can develop a fat embolism that can also result in a fatal pulmonary embolism.
These initial studies that compared more physically active people with those who sat most of the time or didn't engage in any physical exercise clearly showed the dangers of not moving. Although exercise is often considered a voluntary activity, from a health and genetic point of view, it is mandatory for health. The body evolved to expect a certain minimal amount of movement and activity and unless a person regularly engages in such physical activity, the body will always begin to deteriorate. The adage "Use it or lose It" comes into play here, since it's clearly established that whatever isn't regularly used or stimulated in the body eventually dissipates. This is true for all body organs, including the heart, brain, bone, and muscles. Bodybuilders and athletes are well aware that without regular exercise or athletic participation, muscles atrophy, strength declines, and athletic ability is extinguished. I recall a study published a few years ago where they had elite marathon runners stay in bed for exactly 30 days. Although all of these runners began the study with extreme endurance thanks to their habitual running practice, after 30 days of lying around and not moving, their endurance dropped to that of people who had never run at all, much less the 26 miles, 385 yards that constitute a marathon race. This study was alarming in that it showed just how dangerous and how rapidly even extreme fitness can be lost when all activity is curtailed.
Although most people don't engage in marathon running, they do engage in something that can severely adversely affect their health: prolonged sitting. The effects of prolonged sitting weren't known . . .