When is it safe to walk on a frozen lake?

[Beanz]

Miles, walking does not constitute exercise, not for someone of your age.

Vigorous walking and I do walk at twice the speed of pretty much any human being. I do 3 1/2 KM everyday. My walking is like a 45 year old running.

I think you'll find most averagely healthy 45 year olds can run much faster than your speed walking. Bloody hell mate 45 ain't old and yet you go on as though being 31 is like middle age or something.