At this point, we all know the dangers of sitting too much. Sedentary behaviour has been linked to negative health outcomes including heart disease, Type 2 diabetes, cancer, and even an increased risk of death, either from heart disease or other medical problems, according to a 2015 scientific review published in the Annals of Internal Medicine.

Think you’re immune because you run nearly every day? Not so much. People who take less than 5,000 steps per day are setting themselves up for “exercise resistance,” a February 2021 study published in Medicine & Science in Sports & Exercise found.

People who take less than 5,000 steps per day are setting themselves up for “exercise resistance…

What that means, says study author Edward Coyle, PhD, director of the Human Performance Laboratory the University of Texas, Austin, is that “after a workout, your body is more efficient at moving fat from your diet out of your bloodstream and burning (or oxidizing) it, so less fat gets stored in your body.” But if your daily activity level is too low outside of that one hour of exercise, these responses won’t occur, causing your body to hold on to more fat. This is called “exercise resistance.”

In the study, researchers found that cutting a healthy individual’s numbers of steps to between 2,500 and 5,000 per day for just two days led to a 16- to 19% decrease in fat oxidation and a 22- to 23% increase in postprandial plasma triglycerides despite their daily one-hour workout. “Normally, running for one hour would improve your fat metabolism, but it won’t if you’re sitting too much,” says Coyle.

Here’s an important caveat: Those 8,500 steps should occur outside of your workout, says Coyle. “You take 1200 steps per 1km of running, so even if you can fit 8,000 steps in that hour, that’s not going to help you if you’re sitting the rest of the day,” he explains.

This echoes research published in 2019 in the Journal of Applied Physiology, which determined that people who sit for around 13 hours per day and walk less than 4,000 steps per day become resistant to the metabolic benefits of exercise. This study found that people who were sedentary for four days showed the same results on a blood test that measured levels of triglycerides, glucose, and insulin, whether they exercised for an hour on the fourth day or not.

As a runner, you’re already ahead of the game in terms of health—research published in 2020 in the British Journal of Sports Medicine found running as little as 50 minutes per week can help reduce your risk of early death from cancer and cardiovascular-related events. But this latest research emphasizes that that’s not a free pass to melt into your couch the rest of the day. The more consistently you move (even at much lower intensities), the easier it will be for you to maximize the benefits of all the hard work you’re putting in on the road.

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