No I'm not suggesting we all run, but its a free app that can monitor your walking.
The great feature is it can warn you when you have walked every, say, 250 metres or a time like 3 minutes. Then you won't push yourself too far and you know when its sensible to head back home.
Here is my log:
BTW: Daughter uses it for 5k and 10k runs, she is doing a half marathon to raise money for NRAS.