Prolonged sitting can harm health in several ways, raising the risk of obesity, type 2 diabetes and heart disease. It can also lead to back pain, muscle weakness and poor posture. But with many jobs requiring people to sit for hours at a stretch, taking steps to counter these effects has become increasingly important.

A new study from the University of Birmingham suggests that eating foods rich in flavanols may help protect men’s blood vessels from the negative impact of long hours of sitting. Flavanol-rich foods include tea, cocoa, berries and apples.

Study highlights risk from uninterrupted sitting

Sitting for extended periods reduces the blood vessels’ ability to function properly. Earlier research has shown that even a 1% drop in vascular function, measured through flow-mediated dilatation (FMD), can raise the risk of cardiovascular conditions, including heart disease, strokes and heart attacks, by 13%.

The latest findings, published in the 'Journal of Physiology', examined whether flavanol-rich foods could counter the fall in vascular health caused by prolonged inactivity. The study focused on 40 healthy young men divided into two groups based on fitness levels. Participants consumed either a high-flavanol cocoa drink (695 mg per beverage) or a low-flavanol version (5.6 mg) before sitting for two hours.

Women were not included due to fluctuations in oestrogen levels, which can alter the effects of flavanols on vascular function. Researchers said this needs further investigation.

Flavanols showed a strong protective effect

Both high- and low-fitness participants who consumed the low-flavanol drink experienced a decline in FMD, increased diastolic blood pressure, reduced blood flow and lower leg muscle oxygenation. Meanwhile, those who consumed the high-flavanol drink did not show any decrease in FMD in either arm or leg arteries.

This is the first research to demonstrate that flavanols can prevent sitting-induced vascular dysfunction in healthy young men.

Dr Catarina Rendeiro, Assistant Professor in Nutritional Sciences at the University of Birmingham and lead author, said prolonged sitting, whether at a desk, in a car or on a sofa, can stress the body even without physical movement. “Finding ways to mitigate the impact that uninterrupted sitting has on the vascular system could help reduce the risk of cardiovascular disease,” she said.

Co-author Dr Sam Lucas noted that higher fitness levels alone do not prevent the temporary decline in vascular function caused by prolonged sitting, highlighting the importance of diet.

Adding flavanols to the diet is easy

Flavanol-rich foods are widely available, researchers stressed. Cocoa processed through methods that preserve flavanol levels can be purchased in supermarkets and health food stores. Apples, plums, berries, nuts and black or green tea also serve as convenient sources.

Dr Rendeiro added that consuming flavanol-rich foods and drinks during periods of extended sitting, combined with short breaks to stand or walk, may be an effective way to support long-term vascular health, regardless of fitness level.