If you kept fit while you were young (and are now middle-aged) your present risk of a heart attack or stroke is much lower.

Researchers found that fit young adults were much less likely to develop diseases which can put them at risk of a heart attack or stroke (high blood pressure and diabetes).

In the West, cardiovascular disease is a big killer. The research, which is published in the current issue of the Journal of the American Medical Association (JAMA), was carried out at Northwestern University (USA).

Researchers said that if all young adults in the USA had been fit, the number of present cases of high blood pressure, diabetes and metabolic syndrome would have been 30% lower (metabolic syndrome means a combination of excess abdominal fat, high levels of triglycerides and low levels of good cholesterol).

They studied 4,400 men and women (aged 18 to 30) and monitored them for 15 years. 2,400 of them had their cardiopulmonary fitness re-tested after seven years (to record changes in fitness).

They found that those with low or moderate fitness were twice as likely to develop high blood pressure, diabetes and metabolic syndrome than those who were very fit.

The less fit people were, the fatter they became (and the higher their risk became).

51% of those who were not obese were rated as highly fit while 68% of those who were obese had low fitness.

They also found that improving fitness seemed to have no effect on reducing levels of bad cholesterol (low-density lipoprotein) or high blood pressure. Researchers said that this was because bad cholesterol was more affected by genetics and diet (not fitness).

The main message we should learn from this study (researchers tell us) is that the development of risk factors for heart disease and stroke is not just the natural result of getting older.

Professor Sir Charles George (Medical Director, British Heart Foundation) said, 'Results of the study suggest that adopting healthy lifestyles could avoid or delay the anticipated explosion of type 2 diabetes in middle age and beyond.'

The number of people in the western world who are obese is increasing dramatically (especially in the UK and USA). Diabetes is on the increase, as is hypertension. We should seriously consider our lifestyles and those of our children.