Mail Online 8 January 2013
Millions of parents are putting their children at risk of cancer because they let them spend too long sitting– either  watching TV, playing computer games or surfing the internet. Doctors have today delivered a stark warning  that a generation of youngsters is also at risk of obesity, heart disease and  diabetes because of their  sedentary lifestyles. Even more worrying is that children who do  exercise regularly are still at  risk, because long periods of inactivity could  still lead to obesity.

Experts have now urged parents to limit the  amount of time children spend being sedentary to two hours a day. But a 2011 study by the World Cancer Research  Fund (WCRF) found that the average child in the UK is already exceeding this by  watching more than two-and-a-half-hours of  television and surfing the internet  for an hour and 50 minutes a  day.

…Experts have now urged parents to limit the  amount of time children spend being sedentary to two hours a day. But a 2011 study by the World Cancer Research  Fund (WCRF) found that the average child in the UK is already exceeding this by  watching more than two-and-a-half-hours of  television and surfing the internet  for an hour and 50 minutes a  day. The exact mechanism of how being sedentary  causes cancer is still  relatively unknown. But it’s thought that physical  activity decreases the risk of cancer by reducing inflammation in the body – which is linked to developing the condition, Dr Thompson said. Being active also reduces body  fat – it’s  known that obese people have higher levels of inflammation in the body – and  increases insulin sensitivity, thereby reducing the risk of diabetes. She added: ‘Being overweight also increases  levels of certain  hormones such as oestrogen, and this has been linked with an  increased  risk of certain cancers, such as breast.’ Indeed, the most physically active women are  20 per cent less likely to  get the disease than their most sedentary  counterparts, according to Cancer Research UK. Furthermore, an increasing body of research  is linking a lack of  physical activity to between 6 and 10 per cent of all  cases of heart  disease, type-2 diabetes, and breast and bowel cancer. The charity says a review of several studies  showed a 24 per cent risk  reduction for colon cancer in the most versus least  active men, and a 21 per cent risk reduction in the most active women. http://www.dailymail.co.uk/health/article-2258817/Cancer-warning-Doctors-urge-parents-cut-childrens-TV-time-cut-risk-disease-later-life.html