Beware the chair

Study after study has highlighted the dangers of a sedentary lifestyle that includes extended periods of sitting, and the catchphrase “sitting is the new smoking” has gained traction in the media and in popular consciousness. We asked U of T’s Greg Wells how bad sitting really is. Wells is an assistant professor in the Faculty of Kinesiology and Physical Education at U of T and an associate scientist in physiology and experimental medicine at the Hospital for Sick Children. His research is focused on developing new ways of treating disease using exercise and nutrition.

Jenny Hall: We’ve been hearing a lot in the media lately about the health threats of sitting too much. Is sitting actually that bad? Is it really “the new smoking” as we keep hearing?

Greg Wells: The physical inactivity epidemic is causing all sorts of health problems. It is associated with almost every chronic disease on the planet, including cancer, cardiovascular disease and type 2 diabetes. The World Health Organization has stated that physical inactivity is one of the leading health concerns for the planet, and that it is closely associated with increased rates of non-communicable diseases. Non-communicable diseases are the leading cause of death on every continent except Africa. If it’s not the world’s number one health concern, it’s pretty close.

JH: Is there any research on how much sitting is too much?

GW: We know a couple things for sure. First, humans need to be vigorously active for at least an hour a day. A very small percentage of our society achieves that. Vigorous activity is something above and beyond just walking. Your heart rate is needs to be elevated, and you need to be engaged in something that’s physically demanding for you. An hour of fast walking is an example of vigorous activity.

The other thing we know is that the more physical activity we can incorporate throughout the day, the better. This is because sitting is an independent risk factor. The more you sit, the worse your health is going to be. So in addition to getting the one hour of vigorous physical activity, the more you can intersperse physical activities like walking or moving or getting up to move around throughout the day, the healthier you are going to be.

JH: When you say sitting is an independent risk factor, does that mean that even if you get the hour of vigorous activity a day, you’re still at risk?

GW: Yes. Consider an office worker who’s going to the gym religiously for an hour a day. That’s great. They’ll be way better off than if they never did it at all. The message isn’t don’t do that one hour of exercise—it’s incredibly beneficial. We know that vigorous exercise decreases your risk of breast and colon cancer by up to 50 per cent. But sitting all day is still a problem in and of itself that needs to be addressed.

JH: Are there any guidelines for the other kind of activity you talked about—the kind we should try to be interspersing throughout the day?

GW: The best idea is to try to add short bouts of activity throughout the day. I use the 20/20 rule. For every 20 minutes of sitting, stand up and stretch for 20 seconds. Beyond that, within every two-hour block, try to find 15 minutes to do some activity, be it walking or stairs. Even just standing for a while is better than sitting down.

I tell people to stand up in meetings. If everyone else is sitting, find a spot to stand up in the back. If you’re doing a phone call, get up and do it with headphones while you’re standing.

Fifteen minutes of activity every two hours is a tall order if you’re in an office environment.

It is—until you begin to consider the significant damage that sitting causes. The other thing we have learned that’s emerging is the powerful benefit of physical activity for cognitive performance. We now know that physical activity and exercise activate the areas of the brain associated with memory, learning, problem solving and concentration. So an office worker might think they don’t have time to stretch and move, but I would say to them, you can’t afford not to. Not only is your health going to improve, but your performance is going to dramatically improve as well.

JH: So there’s case to be made the physical activity is good for your brain, too?

GW: Absolutely. I watched a documentary on Bob Marley recently. He has a reputation of being this pot smoking guy, but he was a relentless perfectionist. He didn’t let the Wailers play live until they’d practiced for two years. Before they went into recording sessions, he would make everyone play soccer on the beach. They would never go in to play unless they had been exercising beforehand. Or, if you read Steve Jobs’s biography, he never did meetings sitting down. His big creative meetings were always done walking.

I think there’s a real sound physiology to these stories, and good rationale for incorporating physical activity into your day. You’re changing the way your brain works. You’re actually flooding the area of the brain that you’re using with oxygen and nutrients. It’s like flipping a switch. The fact that we try to do creative mental work sitting down goes against the way the body and brain are meant to work.

JH: What actually happens in your body when you sit for extended periods of time?

The main thing is decreased blood flow. When you move, you push fluid through all of the tissues in the body. That is one of the main ways the body fights off illness, by pushing fluids through what is called the lymphatic system. You actually have two full circulatory systems in your body—most people don’t know that. You have your blood system that everyone’s aware of, but you also have the lymphatic system. Fluids moving through the lymphatic system are how the body catches viruses and bacteria and other invaders and filters them out and kills them. So the primary way to stay healthy is to get up and move. Beyond decreased circulation, you also get decreased flexibility and decreased nutrients supplied to muscles and the brain.

JH: It sounds like stagnation.

GW: It’s absolutely stagnation. Think about a fresh flowing stream versus water that sits. Sitting water becomes stagnant with low oxygen, and viruses and bacteria grow in it. There’s a similar effect inside the human body.

There do seem to be some parallels to smoking here if you think about sitting as a public health problem. A huge public health push—and some high profile lawsuits—in the latter part of the twentieth century changed cultural ideas about smoking. Does something similar need to happen with sitting?

We need intervention and education at every single level. We need to get physical education back in schools and to make sure that communities are built with sidewalks and parks. We need to make sure that cities get built so that people can ride their bikes. We now know enough that people should know better. I think it’s possible that employers could be held accountable in the future for not providing the opportunity for employees to be as healthy as they could be, given what we now know. We need a tremendous push on education about the benefits of physical activity and the risks of inactivity.

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Bernie Kraatz

How tiny particles can ...

Sharon Oosthoek | December 1, 2015

Nanotechnology is most often celebrated for its potential to diagnose and treat human disease. University of Toronto chemist Bernie Kraatz's research is focused on fine-tuning this potential. Kraatz makes nano-sized “hooks” designed to fish out from blood, serum or urine the molecules that signal diseases such as cancer or HIV. The hooks are made of combinations of nanoparticles that can also lock on to the biochemical changes that happen in our bodies when drugs fight these illnesses. This means they can both diagnose disease and monitor treatment. While Kraatz's nanoparticle hooks are still in the testing stage, he has designed them to be embedded in microchips used in hand-held biosensors. These biosensors could one day be used in the field and the hospital to quickly scan biological samples for disease while making sure drugs are working as they should. It is, as Kraatz says, a step toward more personalized medicine. Such biosensors could also help border agents quickly detect DNA indicating the presence of endangered or invasive species in goods. Water treatment workers could test for pathogens such as viruses or bacteria. Right now, testing for pathogens means culturing samples, which can take several days. “We are offering continuous and fast detection,” says Kraatz. Building instructions Kraatz’s nano-sized hooks are made of tiny chemical compounds that mimic larger, disease-signalling biological molecules. “The compounds I make are small compared to the biomolecules we are fishing for, but they retain the ability to bind with them,” he says. Getting these hooks just right requires an intimate understanding of the chemical properties of both the compounds and the biomolecules in our bodies that he wants to identify. Kraatz makes his hooks with nanoparticles of ferrocene. Ferrocene is a crystalline compound composed of iron, carbon and hydrogen. This compound is responsible for first-level sensing and can provide biosensors with a simple read-out. But ferrocene needs help recognizing exactly what it has found. And so Kraatz enlists the help of other nanomaterials — fragments of DNA and/or fragments of peptides, which are short chains of amino acids. The DNA fragments recognize and bind with larger mutant, disease-causing DNA. Meanwhile, the peptide fragments recognize and bind with larger mutant proteins that signal the disease’s progress. The final step in this complicated process involves attaching the ferrocene/DNA/peptide compound to a silicon chip coated in a thin layer of gold nanoparticles. This last piece of nanotechnology, the nanogold coating, conducts electricity in the biosensor's digital reader, which health workers can then consult for results.   A version of this story was originally published by University of Toronto's Edge magazine.  It has been edited for clarity, accuracy and brevity, and is republished here with permission

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ORION staff | October 9, 2015

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Sharon Oosthoek | September 28, 2015

Nipissing University sociologist David Zarifa studies the educational and labour market experiences of disadvantaged youth, and he has good news and bad news. The good news: access to undergraduate education continues to increase for traditionally disadvantaged students, including those from low-income families or whose parents did not continue past high school. The bad news: at the higher levels — post-graduate and professional programs — the playing field is much less level. Zarifa came to this conclusion after a close examination of Statistics Canada’s National Graduate Survey of the year 2000 cohort. The survey looks at the experience of 35,000 undergraduates who completed various programs across all provinces and territories. Sociologists have long known that social origins can influence a student's educational experience, directly through parents’ level of education and indirectly through student performance, aspirations, and academic confidence. But there is very little research in Canada about how social origins influence professional or graduate school attendance. When Zarifa crunched the Statistics Canada numbers, he found nearly 35 per cent of undergrads whose parents had a master’s or doctorate degree entered a professional or graduate level program. That compares to only about 13 per cent of graduates whose parents did not have a postsecondary education. He also found about 21 per cent of graduates without government-sponsored student loans entered a graduate or professional program, compared to only about 14 per cent of graduates with loans above $15,000. Zarifa says he is discouraged to see parent education still has an impact at the graduate and professional level, even when taking into consideration other important factors such as academic abilities, aspirations and the educational experiences of graduates. "You would hope by the time students have their undergraduate degree, they wouldn't have this disadvantage in carrying on and trying to better their career prospects," he says. He hopes his study draws attention to some of the challenges facing groups from less privileged backgrounds: "While more and more students are continuing on into some form of postsecondary education, not all social groups are accessing the most lucrative segments within the postsecondary system equally."  
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Robyn Dugas | August 25, 2015

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