Hi
I agree exercise can be very helpful, and running is easy to do, you don't have to run a mile. You could start of just by jogging short distances. Sometimes running can cause problems for people, shin splints or feel more pain in their feet. If that happens with you, could try riding a bike, I know they sell bikes for about 100 at walmart. But bikes have upkeep though. If that is not an option, maybe a exercise bike, is there a gym near you. But making the effort can help.
I started riding my bike again about a year ago, during the summer I went up and down a flat street which was about a tenth of a mile, just a flat street and when I started riding again this summer I was amazed at how strong my legs were, that I have raised the gears. I am only 24, so you might want to do some of your own research on exercise at an older age.
As far as food you could try eating more foods that increase blood circulation, when you say weakness is it more like your legs falling asleep. If your legs fall asleep does it last a really long time, that can be really bad can be circulation related. How is your heart, Doing some research on blood circulation might help or even going to a doctor.
Yea there are plenty of foods that increase testosterone, foods with vitamin b and zinc increase it, maybe researching that could help.
I guess these are some small things you can do and may help, but im no doctor so if it does get worse then going to a doctor might help, especially if it is a dramatic increase.
Hope this helps