A recent study of over 200,000 Australians suggests that you might want to stand up if you happen to be sitting down right now. This study*, published in the Archives of Internal Medicine, found that prolonged sitting is a health risk independent of physical activity, and adds to the growing body of evidence that people who sit the most die the soonest – and, worse, you may not be able to exercise this effect away.
I don’t know about you, but I thought that last finding was disturbing.
In fact, Aussie researchers reported that not even getting regular physical exercise can outweigh the higher mortality risks associated with sitting more than 11 hours a day. Healthy or sick, active or inactive, the more people sat, the more likely they were to die sooner than non-sedentary people.
If 11 hours of sitting seems an unrealistic standard, consider that if you have a sedentary desk job (as I did for decades), it’s actually not unusual to be sitting down for alarmingly long uninterrupted periods of time each day. Many if not most of my own workdays during a long pre-heart attack career in writing and public relations were certainly spent sitting at a desk for hours on end (preceded/followed by more sitting while commuting to/from work or sitting on planes en route to meetings that involved even more sitting) and followed frequently by additional sitting each evening (eating dinner, reading, watching TV, spending time at movies, concerts or visiting friends and family). Sitting, sitting, and more sitting.
Because I also spent decades as a distance runner during many non-working hours, I would have never described my life back then as “sedentary” – given my running group’s weekly road mileage – despite those long hours on the job sitting at a desk. But this new Australian study’s simple message is:
“While the death risk was much lower for anyone who exercised five hours a week or more, it still rose as these active people sat longer.”
The death rate “rose as active people sat longer”? Why didn’t I have one of those stand-up desks all those years? I still don’t have one, but right now I am standing while typing this on my laptop that’s perched on the high breakfast bar (pictured at left) separating my kitchen and dining room. This is not because I knew about the health dangers of sitting, but merely because I got a new laptop a couple years ago and discovered to my delight that the breakfast bar seemed to be a surprisingly comfortable height for laptop use.
It’s been estimated that the average adult spends 90% of off-work leisure time sitting. But the trouble is, many of us are also spending our non-leisure time all day long sitting as well.
“A Brief History of Sitting”
Anthropologists suggest that humans are not born to sit. We suspect, for example, that ancient civilizations rarely sat, but instead likely knelt on the ground, leaning back on their heels to support their weight. In Eastern Asia, low cushions and mats were – and still are – frequently used to sit upon the ground or floor when necessary. Sitting on a seat with a back and (most frequently) four legs is generally a Western concept known as a chair. Early in their history, chairs were largely used by royalty or respected dignitaries (particularly in the form of thrones) and the simpler, backless version of the chair – the humble stool – became the primary seat of the masses.
Squatting – not sitting – seems to be the globally observed forerunner to the Western chair. And humans, like our fellow primates, have always used the squatting position for important functions like childbirth and bowel movements. (Infants of every culture still instinctively adopt this posture to relieve themselves). By the 1800s when the British ruled India, squatting was considered by the Brits as a sign of primitiveness, while sitting on a European-style chair was seen as a sign of civilization.
And sitting for prolonged periods can also be brutal for our posture and musculature. It places our hip flexor muscles in a shortened, tightened, active position, while lengthening and weakening our hip extensors, and stretching out our glutes and hamstrings. Sitting + typing + intensely focusing on a screen a few inches below and in front of us = slumped shoulders, protracted scapulas, unstable shoulder joints, and tight pecs. Ouch.
Over the decades as a seated writer, I have tried adopting healthier alternatives to sitting on a chair – remember the ergonomic kneeling chair and the exercise ball that works on improving balance and core strength? But it appears that simply standing and moving around might be even better.
The Australian study on prolonged sitting adjusted for other factors such as age, weight, physical activity and general health status, all of which can also affect longterm health risks. It found a clear dose-response effect: the more people sat, the higher their risk of premature death.
Healthy or sick, active or inactive, the more people sat, the more likely they were to die prematurely compared to those with non-sedentary lives. While the death risk was lower for anyone who exercised five hours a week or more, it still rose as these active people sat longer.
In other words, we still need to exercise, but it’s also important to spend less time sitting.
Why is prolonged sitting so comparatively hard on human beings? This study’s researchers concluded:
“The adverse effects of prolonged sitting are thought to be mainly owing to reduced metabolic and vascular health. Prolonged sitting has been shown to disrupt metabolic function. Sedentary behavior affects carbohydrate metabolism through changes in muscle glucose transporter protein content.
“Our findings suggested not only an association between sitting and all-cause mortality that was independent of physical activity but, because the findings persisted after adjustment and stratification for Body Mass Index, one that also appears to be independent of BMI.”
In another Australian study reported in the journal Diabetes Care, scientists at the Baker IDI Heart and Diabetes Institute in Melbourne observed adults who sat for seven hours on some days and who rose every 20 minutes and walked leisurely on a treadmill for two minutes on other days. When the volunteers remained stationary for the full seven hours, their blood sugar spiked and insulin levels were erratic. But when they broke up the hours with movement, even that short two-minute stroll, their blood sugar levels remained stable. The scientists concluded that what was important was simply breaking up those long, interminable hours of sitting.
Last year, the American Cancer Society concluded that a woman who sits more than six hours a day is 34% more likely to die prematurely than a woman who sits less than three hours a day. For men, the differential was 17%.
Dr. Alpa Patel spent 14 years conducting the ACS study, which involved 123,000 people. She sees the need for changes in the workplace, and hopes the public health responses accelerate faster than, for instance, the responses to studies linking smoking to cancer and heart disease.
At work, Patel said, employees should make a point of walking around whenever there is an opportunity, working in at least an hour of movement over the course of the typical workday.
And other than buying a stand-up desk and spending evenings and weekends taking interminably long walks, what can the average person do to mitigate the health risks of prolonged sitting? Here are a few pointers from OnlineUniversity.net:
- Stand up and stretch, squat or walk around several times a day to help blood circulation and get your muscles working.
- Stay active after work and make sure you put aside regular personal time to do something that will raise your heart rate.
- If you must sit, for less strain on your back, sit back at 135 degrees in your chair.
* Sitting Time and All-Cause Mortality Risk in 222,497 Australian Adults. H.van der Ploeg et al, Arch Intern Med. 2012;172(6):494-500.doi: 10.1001 /archinternmed. 2011.2174