From google:

"Resistance training increases muscle strength by making your muscles work against a weight or force. Different forms of resistance training include using free weights, weight machines, resistance bands and your own body weight. A beginner needs to train two or three times per week to gain the maximum benefit."

Let me tell you this. Resistance training gives you your life back. I can attest to that.

Combine it with proper hydration and a good diet and you'll feel like Benjamin Button.