Physical inactivity promotes high blood pressure, diabetes, obesity and non-alcoholic fatty liver disease – and thus, unfortunately, life-threatening atherosclerosis of the heart and brain vessels. In this respect it is hardly surprising when the U.S. endocrinologist Professor James Levine of the Mayo Clinic in Rochester says “Sitting is a downright deadly activity.” Levine has devoted himself for years to the topics of obesity, metabolism and inactivity. Among the core issues of his research is for example the question: why, despite identical caloric intake, and (apparently) the same physical activity, some people get fatter, but others remain slender? One of the main findings, which Levine has won in his studies, is that people who stay slim unconsciously move more than those who tend to become fat. Results have been recorded in investigations, for instance, in which subjects wore special underwear with sensors which register even the slightest movements. Levine found, for example, that the obese subjects spent an average of two hours more than subjects of normal weight on or in a chair.
For sitting is man not designed
How harmful sitting is was shown just last year in an epidemiological study (based on an observation time of 14 years) of more than 120,000 Americans which appeared in the American Journal of Epidemiology: men who spent six hours or more a day sitting had a 20 percent higher mortality than men who spent no more than three hours resting on their backsides. For women, the corresponding difference was even as high as 40 percent. Other studies have confirmed this result, so that Levine can safely say: “Excessive sitting is a deadly activity.” The established problem sadly is: A sedentary lifestyle, which really wasn’t forseen in the process of evolution, is the norm in affluent countries. No wonder then that Levine, in a commentary in the journal Diabetes, prompts his fellow man – in the truest sense of the word – to “get up“.
His comrade in the struggle against “comfort”, Professor Peter T. Katzmarzyk from Pennington Biomedical Research Center in Baton Rouge, also rallies against the sedentary lifestyle of many people in the wealthy countries. He even calls for public policy measures and – of course – for further research (Diabetes) because many questions are still unanswered about which public policies are most promising of success. It’s clear he says, however, that people were made for moving, not for sitting.
Now one might naturally think that a prolonged sedentary period could be easily compensated for by more physical activity. But it does not seem to be quite so easy. The attempt to compensate for the consequences of inactivity by increased physical activity makes just as little sense as the attempt to counter the harmful effects of smoking with regular jogging adds Dr. Marc Hamilton from the Pennington Biomedical Research Center, who has researched the physiology of inactivity for several years, in the New York Times. Sitting or inactivity would lead very quickly to a massive reduction in energy consumption, the effect of insulin drops off within a day, the HDL-C levels fall. The insulin effects on glucose intake fell by around 40 percent in healthy volunteers after 24 hours of sitting according to only one result of research by Hamilton. This adverse effect was then still detectable, when energy intake had been adjusted to the reduced energy demand, Hamilton and his colleagues write in the journal Metabolism.
That inactivity very quickly leads to potentially harmful metabolic changes is also confirmed by nutritional and exercise physiologist Professor John P. Thyfault from the University of Missouri, who has just evaluated the available scientific data on it (Current Opinion in Clinical Nutrition & Metabolic Care). Sitting is in itself – whether in the car, while watching TV or at your desk – life-threatening, says Professor Wendell C. Taylor of the University of Texas in Houston in a recent review work on the relationship between sitting and cardiovascular morbidity and mortality.
Heavy sweating does not need to be the case
Fortunately, the opposite of inactivity does not need to be sports, but rather activity. And it may indeed already be enough, over the years, only to be a bit “brisk”, even small muscle movements seem to count. Studies by Levine showed namely that obese subjects only carried out 1,500 movements daily and were sitting for almost ten hours. Slim farmers in Jamaica, by contrast, according to information from James Vlahos in the New York Times, reached a count of 5000 movements a day and a sitting period of only 367 minutes. Studies among the Amish religious community, in which excess weight and obesity in contrast to their fellow American citizens isn’t rampantly spreading, reveal according to Katzmarzyk that men make over 18,000 steps per day, the women slightly more than 14,000, which is about twice the level of the general population.
The occasional standing-pause is enough
From this perspective, one should favour, if one really has to sit, so-called dynamic sitting – that is, fidgeting on the chair. This should also help prevent back pain by the way, as orthopedic surgeon and sports medicine practitioner Hannes Schoberth wrote in 1989 in his classic work “Orthopaedics of sitting”. Even better is, certainly, to stand up from time to time, since many breaks – even if only lasting a minute – strengthened the heart and reduced the hip girth, as reported by Dr. Genevieve N. Healy of the University of Queensland and her colleagues a few months ago in the European Heart Journal . The researchers studied 4757 adults who were equipped with an activity meter placed at the hip which worked like a pedometer.
Those subjects who stood up most frequently reported the lowest blood-fat levels, the lowest blood sugar levels and the lowest waist circumference. “I suppose one could prevent cardiovascular disease, to a considerable extent, when the whole population would sit less,” Healy is quoted as saying in the Süddeutsche Zeitung. What particularly surprised the researchers was “that even minor activities had positive impacts – getting up when talking on the phone, getting up and going to a colleague in the neighboring room instead of calling, for example, or using the toilet one floor higher.” So there is another good reason from time to time to keep a chat going in the office.