New Runner at 49 question

I started running within the last 7 months. I've been slowly building up my miles. I've been incorporating a Galloway run run walk method. But I just began recently going by heart rate and I am trying to keep my heart in the Arabic zone to build-up my Arabic base. Yesterday I did my longest run ever at 14.2 miles at a very slow pace. At about mile 6 or 7 my knees began to feel tight. Even at a low heart rate my legs were really feeling it at the end of the 14 miles. My question is if I just continue to run Consistently will my legs become stronger and be able to endure the long runs?

Yes, your legs will become stronger. The Galloway method (or any walk run strategy) really helps you extend the distance beyond what you could do trying to run the whole time, but it’s not going to prevent eventual fatigue. But as you keep training, like any training, your fitness will improve, and you can go longer and longer distances — or do the shorter distances you used to do but with less walking or no walking.

Thanks for the reply. That is encouraging!