Sitting for long periods—like when you’re working at a desk, driving, or watching TV—can be bad for your blood vessels and heart health.
But a new study from the University of Birmingham shows that drinking a flavanol-rich cocoa drink before sitting down might help protect your blood vessels.
The study looked at how flavanols, which are natural compounds found in foods like cocoa, apples, berries, and tea, affect the blood vessels during two hours of sitting.
Even young, healthy men can experience a drop in blood vessel function from just two hours of being still, and that’s a concern because poor blood flow can raise the risk of heart disease, strokes, and heart attacks. This new research shows that certain foods may be able to help.
In the study, 40 young men were split into two groups: one group with higher fitness levels and one group with lower fitness levels. Each participant drank either a high-flavanol cocoa drink or a low-flavanol cocoa drink, and then they sat for two hours.
The researchers measured how well their blood vessels were working before and after sitting, including blood pressure, blood flow, and oxygen levels in the leg muscles.
Those who had the low-flavanol drink saw a drop in how well their arteries worked, no matter how fit they were. Their blood flow and muscle oxygen also decreased.
But for those who had the high-flavanol drink, their blood vessels stayed healthy—even after sitting for two hours. Their results didn’t show the same declines, showing that the cocoa drink helped protect their blood vessels from the harmful effects of sitting.
This is the first study to show that flavanols can stop blood vessel damage caused by sitting, and that even people who are very fit can still benefit from flavanol-rich foods. It also shows that being fit doesn’t protect you from all the effects of sitting too long.
Dr. Catarina Rendeiro, who led the study, said that many people spend hours sitting every day, and this can stress the body even though we aren’t moving. She said that finding ways to protect the body during these times could lower the risk of developing heart disease.
Another researcher, Dr. Sam Lucas, explained that drinking cocoa high in flavanols kept people’s blood vessel function the same as it was before sitting, no matter their fitness level.
One important note is that this study only involved men. The researchers chose not to include women because hormone levels during the menstrual cycle could affect how flavanols work. Future studies may explore this in women too.
You don’t need special cocoa powder to benefit from flavanols. Foods like apples, berries, plums, and tea also contain them.
Some cocoa powders sold in supermarkets are processed to keep these helpful compounds. So even small changes to your diet, like having a cup of tea or a piece of fruit, might help keep your blood vessels healthy—especially if you spend a lot of time sitting.
This study adds to growing evidence that small daily choices in food can make a big difference for your heart and blood vessel health, no matter how fit you are.
Adding flavanol-rich foods to your routine, along with taking short breaks from sitting to stand up or walk, could support your long-term health and reduce the risks that come with a sedentary lifestyle.
If you care about heart health, please read studies about the stuff in your mouth that can increase heart attack risk and statin alternative lowers risk of heart disease as well as cholesterol levels.
If you care about heart health, please read studies that Manganese can help clear arterial plaques and treat heart disease and Aspirin use linked to heart failure.
The study is published in The Journal of Physiology.
Copyright © 2025 Knowridge Science Report. All rights reserved.
