You may not think twice about sitting down at your desk for hours during a workday—or, for that matter, winding down on your couch after—but Mayo Clinic experts say that sitting for more than eight hours a day “had a risk of dying similar to the risk posed by obesity and smoking” when reviewing studies on the subject.
While sitting for too long can raise your risk of several diseases, including cancer and diabetes, one of the key threats has to do with heart health. In addition to weakening the muscles of your heart, prolonged inactivity can also thicken or harden the blood vessels and arteries as plaque builds up on their inner lining—a condition known as atherosclerosis. This can ultimately increase your risk of heart attack, stroke, vascular dementia, and other serious cardiovascular problems.
However, a new October 2025 study shows that there are heart-protective benefits to eating certain foods on those less active days. Published in The Journal of Physiology by a group of sport science researchers, the study says that consuming cocoa or tea, berries, and apples could protect blood vessel flexibility. This is thanks to those drinks and foods being rich in plant chemicals called flavonoids—which help give produce bright coloring. The Cleveland Clinic explains that flavonoids can offer antioxidant, anti-cancer, and anti-inflammatory benefits.
The small study included 40 healthy young men, divided into two groups based on their fitness levels. The men were instructed to consume either a high-flavonol cup of cocoa or a low-flavonol cup of cocoa, then complete a two-hour period of sitting.
Before and after sitting, the researchers tested for measures of arterial flexibility, including blood flow, blood pressure, and superficial femoral artery flow-mediated dilatation—this tests how well an artery can widen in response to increase blood flow.
“Importantly, after the high-flavanol drink, both fitter and less-fit participants kept their [arterial elasticity] the same as it was before sitting for two hours,” said researcher Sam Lucas, a professor of cerebrovascular, exercise and experimental physiology at the University of Birmingham, in a news release. Meanwhile, the men who drank the low-flavonol cocoa experienced a reduction in the flexibility of their arm and leg arteries.
It’s worth noting that women were not included in the study, as the research team explained that “changes in oestrogen levels during the menstrual cycle are suspected to affect the impact of flavanols on vascular health during sitting.” Future research should further investigate this particular angle, they remarked.
Though the study focused its experiment on cocoa, the authors write that they believe other high-flavonol foods, such as apples, berries, and tea, should produce similar effects, saying that consuming such foods and drink during sedentary periods—whether on its own or “in combination with other strategies,” such as taking breaks to move from sitting—could reduce the systemic impact of sitting.
“Consuming high-flavanol foods and drinks during periods spent sitting down is a good way to reduce some of the impact of inactivity on the vascular system,” concluded senior researcher Catarina Rendeiro, assistant professor in nutritional sciences at the University of Birmingham.
The team points out that it’s relatively easy to find such high-flavonol foods in grocery stores, though one researcher suggests looking for cocoa products “processed through methods that preserve flavanol levels.” Taking mini breaks throughout the day to get up, stretch, or take a short walk can give your body a much-needed boost, too.
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