Audax rides

How exercise in old age prevents the immune system from declining
http://www.bbc.co.uk/news/health-43308729

Doing lots of exercise in older age can prevent the immune system from declining and protect people against infections, scientists say.
They followed 125 long-distance cyclists, some now in their 80s, and found they had the immune systems of 20-year-olds.
...
I met a dozen of the cyclists, on a morning ride in Surrey. Despite the bitter cold, they were universally cheerful, and clearly used to riding in all weathers.
They are members of Audax, a long-distance cycling organisation that organises events ranging from 100km to 300km.

Lol. But also, only 300km?