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.
In fact, researchers argued in 2020 that sedentary behaviour and inactivity has reached a pandemic status in the U.S., according to commentary in the journal Progress in Cardiovascular Diseases. Not surprising, considering how many people have been stuck at home for the better part of a year.
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.
When you do acute exercise—like one hour of moderate-intensity running, in the case of this study—there are two physical responses that can be measured within your body the next day: a lowering of the postprandial plasma triglyceride response to a high-fat meal and increased fat oxidation.
What that means, says study author Edward Coyle, Ph.D, 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-per cent decrease in fat oxidation and a 22- to 23-per cent 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.
Meanwhile, taking at least 8,500 steps per day, the researchers found, protects you against exercise resistance in fat metabolism. Translation: Fat metabolism may be influenced more by the inhibitory effects of inactivity than by the stimulating effects of a workout.
Here’s an important caveat: Those 8,500 steps should occur outside of your workout, says Coyle. 'You take 2,000 steps per mile 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.
Just like in the more recent study, these researchers recommend taking at least 8,000 steps per day to avoid becoming exercise resistant. So even if your run covers 8,000 steps in one go, you should absolutely be taking walk breaks throughout the day. Coyle says he’s still researching the timing of the steps, but recommends getting them in earlier to keep your metabolism up before a run workout so you can get the most benefits afterward. After a run, make sure to get up and walk around at least once an hour for a few minutes, or if possible, pop outside to do a few laps around the block during your work breaks (even if you’re WFH right now). It’ll make a big difference.
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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