I did this exact workout regime three years ago, and lost a little weight, and got into better shape, but now the same exercises leave me feeling exhausted and achy for days on end. (NRLFW and low-impact cardio - gave up on running for now.) During the exercise I feel fine, like I'm even taking it a little easy, and I am getting demonstrably stronger. But right now I'm nursing a stiff neck that doesn't seem to be getting better after multiple days, and my legs are sore all the time. Is this just what happens after hitting 30? Should I just keep pushing through it?