If you spend long hours sitting at a desk, on the couch or behind the wheel, your blood vessels might not be thanking you, but a little cocoa could help.
New research from the University of Birmingham shows that eating foods rich in flavanols, such as tea, berries, apples and cocoa, can protect blood vessel health from the negative effects of uninterrupted sitting. The findings, published in The Journal of Physiology, suggest that flavanol compounds may help maintain circulation even when the body stays still for hours at a time.
“Whether we are sitting at desks, behind the wheel of a car, on a train or on the sofa reading a book or watching TV, we all spend a lot of time seated,” said Dr. Catarina Rendeiro, assistant professor in nutritional sciences at the University of Birmingham and the study’s lead author. “Even though we are not moving our bodies, we are still putting them under stress. Finding ways to mitigate the impact that sitting for uninterrupted periods has on our vascular system could help us cut the risk of developing cardiovascular diseases.”
Previous studies have shown that sitting for long stretches can reduce vascular function, a measure of how well blood vessels widen to support blood flow. A 1% decline in this function is associated with a 13% higher risk of cardiovascular disease. The Birmingham team wanted to know whether flavanols, a group of plant compounds found in certain fruits, teas and cocoa beans, could prevent that decline.
To find out, researchers studied 40 healthy men who drank either a high-flavanol cocoa beverage or a low-flavanol version before sitting for two hours. Regardless of their fitness level, men who consumed the low-flavanol drink experienced reduced blood vessel flexibility and circulation in their arms and legs. But those who drank the high-flavanol cocoa maintained healthy vessel function throughout the sitting period.
“Our experiment indicates that higher fitness levels do not prevent the temporary impairment of vascular function induced by sitting when only drinking low-flavanol cocoa,” said co-author Dr. Sam Lucas, professor of cerebrovascular, exercise and environmental physiology. “Importantly, after the high-flavanol drink, both fitter and less-fit participants kept their vascular function the same as it was before sitting for two hours.”
The researchers say this is the first study to show that flavanols can prevent sitting-induced vascular dysfunction in healthy young men and that the benefits appear independent of baseline fitness. The study did not include women, as hormone fluctuations across the menstrual cycle can influence vascular responses to flavanols, but the team plans to explore that in future work.
“It is actually quite easy to add high flavanol foods to your diet,” said PhD student Alessio Daniele. “There are cocoa products available in supermarkets and health stores which are processed through methods that preserve flavanol levels. If cocoa isn’t your thing, fruits like apples, plums and berries, nuts, and black and green tea are all common kitchen staples and are readily available.”
Rendeiro added that combining such foods with simple breaks from sitting, like standing or walking for a few minutes every hour, could help enhance long-term vascular health.
“Our research shows that 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,” she said.
The study was funded by the University of Birmingham.