Great. After surviving three cancer battles and several other life-and-death dramas, I just discovered I’m likely to succumb to Death by Sitting.

And I’m probably gonna have a lot of company.

Like many people, I’ve bonded with my computer. We spend our days and many evenings working and playing together. So of course, while we’re working, I’m sitting in a desk chair in my office. And if I’m working or playing on the laptop after hours, I’m often sitting in a recliner. Other times, I may be sitting in a car, library, theater, church, restaurant, stadium, waiting room, friend’s home, or on the dock of the bay.

But I make up for all that sitting by spending, oh, 30 minutes a day on the treadmill or hopping around on the Wii Fit. A couple of days a week, I do a little weight-lifting … a few chores around the house. So I’m active, right?

Uh … no. And as with most things affecting humans, the dangers of this inactivity can best be explained by rats.

Couch potato ratatouille

According to studies published last year by the British Journal of Sports Medicine, most of us think we’re active because we’re working and putting in a little time at the gym. But we’re really just “active couch potatoes” who spend about 15.5 hours a day sitting at a desk, in a chair, or in a vehicle. Tack on eight hours of sleep and … get the picture? (We’re slugs.)

When scientists confined rats to a small space, restricting their movements in order to simulate humans’ self-inflicted sluggishness, the result was increased fatty acids in the blood, signs of insulin resistance, and cellular changes in the muscles that could lead to heart disease, diabetes, and other illnesses. As their muscles atrophied from consecutive hours of nonuse, the rats lost interest in ambling about even after their restrictions were removed. Give them a big-screen TV and they’d probably have been happy to retire from scurrying altogether and just sit there watching Rizzo The Rat, Ratatouille, and old Ben and Willard films.

Alphabet soup

Unfortunately, studies have shown that the recommended 30 minutes a day of moderate to vigorous exercise isn’t enough to offset the 23.5-hour lying/sitting combo. So what’s the answer? A varied diet of frequent exercise snacks.

The folks who study these things rate the intensity of activities in units called METs—which stands for metabolic equivalent of task. The important thing to remember is the higher the MET, the more energy you’re expending. Here’s an overview:

• Sedentary activity requires only 1 to 1.5 METs. Lying down or sitting quietly = 1 MET.

• Light-intensity physical activity (LIPA) requires 2 to 3 METs. Basically, this means standing with some movement—for instance, performing daily chores such as mopping, dusting, and cooking that we now frequently delegate to cleaning services, restaurants, Stouffer’s, and Papa John’s.

• Moderate-intensity physical activity (MIPA) requires 3 to 5.9 METs. Moderately paced walking = 3 to 4 METs.

• Vigorous-intensity physical activity (VIPA) is any activity requiring more than 6 METs. Running = 8 METs.

So to avoid Death by Sitting, we need to continue with our half-hour of scheduled MIPA/VIPA. But we also have to season those hours of sedentary activity with regular doses of LIPA and MIPA. Take hourly breaks from the computer, desk, television to stand up and walk around, do a few squats, dust something. It doesn’t matter what you do as long as you’re up and moving for a few minutes every hour. Otherwise, the Grim Reaper may come calling years ahead of schedule—and you won’t even have the energy to run.