The best indicator for men of cardio-respiratory fitness is their girth.

You can find out with a tape measure - that’s all it takes. Forget calculating muscle vs fat and so on (the BMI or body fat index); the waist measurement is easier and more accurate too.

This is the finding of Dr Jean-Pierre Després and his colleagues at the Hôpital Laval Research Centre in Quebec (published in the Archives of Internal Medicine). The healthier a man is the less weight he carries around the abdomen. Surprisingly this is true regardless of the body mass index.

This reinforces the notion of “apples vs pears”.

That is, the typical male vs female ways of carrying extra weight. It is the apples (those who carry weight around their middle - usually men) who are in danger of heart attack, not the pears (who carry the extra weight below their waist - usually women before menopause).

And the best way to increase fitness and reduce this dangerous waist size? Exercise, get fit.

The waist measurement is useful as a measure of fitness, not something on its own.

The fitter you are the less likely you are to have a heart attack - regardless of your body mass index. And the easiest indicator of your fitness is your waist measurement.

For women the story is more complicated because of menopause, but for men it is really this simple.