We have read reports and studies that exercise increases brain function. Yay! You actually are smarter, better looking and more awesome when you exercise.
But if you stop.. apparently, you lose all of those benefits.
In three weeks, give or take, you are at the brain function (and it feels like the muscle strength I must add) of someone who doesn’t exercise.
If that is not a reason to keep doing at least moderate exercise even when not in training, I don’t know what is. So get out there and walk, jog, rake the leaves and shovel the walk. Make sure your brain is in shape so you can make the good decisions to get out of dodge and into the hills.