The average American spends most of their waking life sitting down, which is associated with an increased risk of death even among people who go to the gym after work and exercise regularly. Doing lots of sitting may double our risk of diabetes and heart disease while significantly shortening our lifespan, even at the highest levels of physical activity. Sitting six or more hours a day may increase mortality rates even among those running or swimming an hour a day, every day, seven days a week. Why though?
One factor may be endothelial dysfunction, the inability of the inner lining of our blood vessels to relax our arteries normally in response to blood flow. Just like our muscles atrophy if we don’t use them, when it comes to arterial function, it’s ‘use it or lose it’ as well. Increased blood flow promotes a healthy endothelium. The cells lining our arteries can actually sense the sheer force of the blood flowing past. That flow is what maintains the stability and integrity of the inner lining of our arteries. Without that constant tugging flow, it may help set us up for heart disease.
We actually have some data now suggesting that treadmill desks may improve the health of office workers without affecting work performance, and walking may be preferable to standing in terms of clearing fat from our bloodstream, which can play a role in endothelial dysfunction.
What if our office can’t accommodate a standing or walking desk? Within an hour of sitting, blood starts pooling and blood flow starts to stagnate, so the more we can take breaks the better. Preliminary evidence from observational and interventional studies suggests that regular interruptions in sitting time can be beneficial. And it doesn’t have to be long. Breaks could be as short as one minute and not necessarily entail exercise, just something like taking out the trash during commercials may be beneficial.
I’ve talked about the effects of different diets on endothelial function (See Eggs and Arterial Function, Walnuts and Arterial Function, and Dark Chocolate and Artery Function) and how certain foods in particular—nuts and green tea—are beneficial for endothelial health. Recently, researchers tried out curcumin, the yellow pigment in the spice turmeric.
They showed that regular ingestion of curcumin or up to an hour a day of aerobic exercise training significantly improved endothelial function. And the magnitude of improvement in endothelial function was the same. So does that mean we can just be a couch potato as long as we eat curried potatoes? No, the combination of curcumin and exercise may work even better than either alone.