This gal makes a lot of sense to me:
Who Will Die First when SHTF: A WARNING - YouTube
Personally, I can barely bench press anything, I'm 145-155 and 5'10", haven't done pull ups or pushups in years, and my hip starts acting up just walking around the block. In other words, I'm scrawny and out of shape. On the flip side, I can haul a dresser up a flight of stairs on my back, spend half an hour tossing my 1 year old in the air just to make him giggle, or strap a 40lb camera bag to my back and jog through the woods for a couple miles. I can forget to eat for a couple days (and frequently do), or polish off a large pizza in one sitting. Exercise bores me, so I never do it. But doing things is interesting. I hate going to a gym, but I'll climb a tree, hang from a branch with 1 arm and 1 leg, and hack off other branches with a machete. I can't do planks or lunges, but I can balance on top of a 1/2" wide cedar fence barefoot and fix the gutters.
Being able to survive has little to do with how many pushups you can do, or what you can bench press. It does have a lot to do with having a healthy metabolism, and the ability to perform tasks needed in a survival situation.
Go to the gym and run a couple miles on a treadmill, or chase a dog chasing a raccoon through a slough? Do 40 pull ups, or climb 20 feet up into a tree to get a bag full of apples? Get winded by jumping up and down, or play fighting with the dog? I know what I'd choose, and it doesn't involve rubber mats, sweat rags or TVs on the wall to distract you from realizing how bored you are. Besides, being able to fight a dog without being bitten is a GREAT survival skill, right?