You asked, we answered. As a Patreon perk, many of our patrons voted from an episode on the dangers of sitting. This has been in the news a lot recently; it’s also the topic of this week’s Healthcare Triage.

[Healthcare Triage Intro]

There’s a wealth of literature that shows that sitting can be linked to obesity or being overweight. And of course, those things can be associated with bad health outcomes. But what’s concerning is that even after you control for those things, it appears that sitting is still really bad for you.

For instance, a study published in 2009, in the journal Medicine & Science in Sports & Exercise, followed more than 17,000 Canadians for twelve years on average. They found that levels of sitting were associated with higher risks of death, with those sitting the most having an increased risk of death of more than 50%. In fact, the mortality rates for those who sat almost none of the time, one-fourth of the time, half the time, and three-fourths of the time, or almost all of the time were 87, 86, 105, 130, and 161 per 10,000 person years.  Those differences are scary!

A meta-analysis was published just two years ago in the Journal of the National Cancer Institute that examined all studies that looked at sitting time and the risk of getting cancer. They found 43 observational studies that included almost 69,000 cases of cancer. And the news wasn’t good: sitting was positively associated with colon cancer (with a relative risk of 1.24), endometrial cancer (relative risk 1.32), and lung cancer (relative risk of 1.21). Here is where it gets really bad, though: adjusting for physical activity made no difference.  This means that even those who tried to exercise couldn’t wipe away the dangerous associations of being sedentary.

A meta-analysis, published this year in Annals of Internal Medicine, reviewed 47 articles that looked at sedentary behavior while adjusting for physical activity. They found that more sitting was associated with increased all-cause mortality (hazard risk of 1.24), cardiovascular disease mortality (hazard risk 1.18), cardiovascular disease incidence (hazard ratio 1.14), cancer mortality (hazard ratio 1.17), cancer incidence (hazard ratio 1.13), and type II diabetes incidence (with a hazard ratio of 1.91).

One study found that adults who spend six hours a day sitting and watching TV lost about 4.8 years of life on average versus those who don’t. Or you can put it this way, every time you sit and watch an hour of TV, you could be taking 21.8 minutes off of your life.  If you want to panic, it’s been calculated that each cigarette you smoke takes only 11 minutes off your life.

Why is all this so? That’s a harder question to answer and unfortunately we can only speculate. Obviously some of the harm comes from sitting leading to weight gain and obesity, which are linked to all the diseases and deaths that I mentioned already. But there’s likely more going on.

Some scientists believe that sitting signals the body to shut off certain enzymes that help clean fats out of the bloodstream. It might also prevent the body from properly regulating inflammation and blood clotting, and you can’t necessarily fix those things with physical activity.

It’s not all bad news though; this is fixable especially for many Healthcare Triage viewers who tend to be relatively young. You can NOT sit so much. There’s research to back this up.

A study published in 2012 in Diabetes Care took 19 overweight or obese adults and put them through a randomized three-period, three-treatment crossover trial. The first arm was uninterrupted sitting; the second was seated with 2-minute bouts of light-intensity walking every 20 minutes; and the third was seated with 2-minute bouts of moderate-intensity walking every 20 minutes. They gave them a standardized test drink after an initial 2-hour period of interrupted sitting. And then they measured their glucose levels. What did they find? That breaking up sitting time with 2-minute bouts of light- or moderate-intensity walking lowered postprandial glucose and insulin levels. In other words, it appeared to improve glucose metabolism, which could reduce cardiovascular risk.

Another study published a year later in the American Journal of Clinical Nutrition took 70 adults and ran them through a randomized crossover trial. There was a prolonged sitting intervention involving sitting for 9 hours, a physical activity intervention involving walking for 30 minutes and then sitting for a while, and a regular-activity-break intervention involving walking for just under two minutes every 30 minutes. Participants consumed a meal replacement beverage at 1, 4, and 6 hours.  And get this: the frequent and regular short activity breaks were more effective than continuous physical activity at decreasing higher blood sugar and insulin levels in healthy, normal-weight adults.

And look, I get that this is mostly observational data and I wish we had more randomized controlled trials but this looks pretty bad and it’s easy to fix. Getting up and walking once in a while, even for a few minutes, resulted in better outcomes with respect to blood sugar control than exercising but sitting for long periods of time.

I used to make fun of my Apple watch for pinging me to stand up every hour and walk around for a minute or two. No longer! It’s the one metric I make sure I never fail to achieve each day. I make sure to walk around in my office building more. I stand whenever I talk on the phone, and I pace. And it turns out, that may be doing me more good than the P90X3 that I suffered through earlier this year. Who knew? Maybe from now on, we should ask all of you to stand and walk around while you watch Healthcare Triage. Might help you live longer.

[Healthcare Triage Outro]

Healthcare Triage is supported in part by viewers like you through patreon.com, a service that allows you to support the show through a monthly donation. We’d especially like to thank our honorary research associates Cameron Alexander and Qadeem Salehmohamed. Thanks Cameron and Qadeem!

If you’d like to support the show, more information can be found at patreon.com/healthcaretriage