According to the World Cancer Research Fund, we are putting ourselves at risk of developing cancer because of our lack of physical activity.
The alert comes after figures suggested that women in the UK have the 10th highest rate in the world for cancers linked to being sedentary.
Experts have estimated that 12% of bowel and breast cancers and one in 10 womb cancer cases in the UK could be prevented if women did more exercise.
In 2012, almost 80,000 British women were diagnosed with these cancers, at a rate of 133 women per every 100,000, the charity said.
In Barbados, which tops the chart, almost 155 women in every 100,000 developed bowel, breast or womb cancer.
"It is a major concern that women in the UK are placed so highly in the world for cancers that are partially preventable through people being more physically active," said Dr Rachel Thompson, head of research interpretation at the World Cancer Research Fund.
"These figures reflect the sedentary lifestyles of many people in Western countries, with lots of us spending too much time sitting around and not incorporating physical activity into our daily routine.
"Regular activity can help strengthen the immune system, keep hormone levels healthy and the digestive system in good shape, all of which help reduce our chances of developing cancer."
The charity has launched its 100 Calorie Challenge to help people reduce their risk of cancer through small lifestyle changes, including being more physically active.
Here is the World Cancer Research Fund list of the 10 countries with the highest rates of breast, bowel and womb cancers in women in 2012, along with the estimated rate per 100,000 women.
Barbados - 154.9 per 100,000
Belgium - 154.5 per 100,000
Denmark - 154.2 per 100,000
Netherlands - 145.3 per 100,000
France - 140.1 per 100,000
Iceland - 136.3 per 100,000
Luxembourg - 134.9 per 100,000
USA - 134.4 per 100,000
Bahamas - 134.3 per 100,000
United Kingdom - 133.3 per 100,000