One day as my focus faded from studying, I thought about how much I had been sitting that day, and how many hours I spend sitting every day. After logging in eight hours of sleep (if I am lucky), I am left with 16 waking-hours. On average, I can tally nine of these hours in a chair, whether sitting in class, studying or eating. Even when you size-up my 30-minute workouts and lighter daily activities, the majority of my days are spent motionless. We all experience this excessive sitting, and I challenge you to think about it as more than a necessary act – or lack thereof. As I’ll share below, excessive sitting is now being considered a major risk factor for the development of chronic conditions such as diabetes and cardiovascular disease.
As a New York Times reporter put it so well, “This is your body on chairs” (insert provocative CSI-style zoom-in to body): The assault on your metabolism begins as your calorie use dwindles to around 25 percent as compared to walking. Several researchers have published the sedentary body’s decline in sugar uptake, as insulin sensitivity drops by up to 40 percent. Several studies also show that our means of vacuuming fat from the bloodstream are also diminished after long periods of inactivity – particularly an enzyme called Lipoprotein Lipase (LPL). Increased levels of triglycerides and lipids and lower levels of HDL (the good cholesterol) have been measured in multiple studies. The combined harms of excessive sitting, especially over a lifetime, leave one with an increased risk for type 2 diabetes and cardiovascular disease.
This whole time many of you have been thinking, “Surely my exercise routine of 40 minutes, four times a week, protects me from these problems.” Experts would tell you that this is like excusing a cigarette a day with some time on the treadmill – the health effects take their toll regardless of your fitness level. Intense exercise is simply not enough to burn off the calories equivalent to our daily intake, even though it may boost our metabolisms throughout the day. Think of your metabolism as a car on the freeway – and for a frame of reference, Lance Armstrong is an Indy 500 car. The goal is to keep your engine running to maintain a high speed. When you are inactive, you are pressing the brake pedal, and your relatively short bursts of exercise are punches on the accelerator. Put the time difference into perspective, and you can imagine how slowly this car would be moving.
The silver lining in all of this is that there may be a way to ease up on our brake pedals, according to Dr. James Levine, a physician at the Mayo Clinic who is pioneering solutions for our “chair-based lifestyles.” This is where things get so simple! All it takes are minor activities, and more of them, such as standing or pacing while studying or on the phone, taking the stairs, cooking more – simple alternatives to long-term inactivity. He has coined this type of activity as non-exercise activity thermogenesis (NEAT), which realistically accounts for most of our caloric burning throughout the day. He and other researchers have demonstrated these interruptions of inactive time directly decrease health risks. Study subjects had increased insulin sensitivity, lower triglyceride and lipid levels, and long-term studies had smaller waistlines and BMI’s.
Students and those with desk-based jobs should be especially aware of the risk factors and their individual solutions to their inactivity. So next time you hear about treadmill desks, or the use of exercise balls as office chairs, consider the benefits of these solutions. I’m gyrating on an exercise ball right now, and it’s fantastic! If you need baby steps, perhaps start by avoiding the elevator.