I only really walk down my horse when it’s cold because he lives out. When it is really cold then I untack him and as soon as his sweat is cold then I put a light blanket on so he doesn’t freeze and his muscles don’t seize up (a cooler or fleece). I then just walk him until his breathing is back to normal.
Until breathing and heart rate return to normal levels
I personally do the 1st one. My care horse walks 24/7 outside and isn't shaved. Which means his sweat will stay for a long time and I'm really not going to walk him down for an hour haha