Obesity and lack of fitness raise the risk of illness by impacting negatively on the body’s internal chemistry, research suggests.
A US team found levels of white blood cells were highest in men who were unfit and overweight.
White blood cells are key to fighting infection, but high levels can be a sign of inflammation, which is linked to coronary heart disease.
A team from the Pennington Biomedical Research Center carried out tests on 452 healthy men who were taking part in a long-term study of fitness. Blood tests were taken, and analysed for their content of various types of white blood cell.
After taking account of age, the researchers found that all groups of white blood cell were lowest in the men who were most physically fit.
The greater proportion of body fat a man had, the higher his white blood cell count was.
Total white cell count was highest in men who had a combination of higher body fat and lower levels of physical fitness.
Levels were also high among men with lower body weight but lower levels of fitness. However, a high degree of physical fitness negated the effect of extra body fat.
Read more at BBC News