Do not start getting Testosterone shots at the age of 36 unless your T level is below 300.
300 is very low and definitely would need trt...mine was around 450 and was told by the specialist that it needed to be higher...especially if i was going to work out 5-6 days a week... even at 45-50yr and doing no post cycle therapy, you will almost definitely fully recover from a simple Test cycle in no time... but, to insure that you do, you take nolvadex and clomid (orals) for 3-4 weeks and you will be producing your own Test again before you finish them... test, run at moderate doses, is harmless... thats just basic stuff that most still dont understand...you will recover
its when you start adding other compounds, dont take anything to counter side effects on cycle and dont do any post cycle therapy, that you risk a future of test replacement therapy... of course, thats getting into bodybuilding shit and thats not what he is talking about anyways...
here are 2 good charts for info on test levels... small sample sizes, but you get the picture... so many people listen to clueless drs. about test... and they continue to feel like shit, tired, lazy and unproductive and have low sex drive...
http://www.artofmanliness.com/2013/01/16/normal-testosterone-levels/
although its the staple for bodybuilding, most have the wrong idea about test...by itself, its not going to muscle you up and make you huge or none of that shit... it will give you more appetite, sex drive, improve attitude and well being and rehab muscles faster...
i was just throwing it out there though, but you really should get a physical and blood work done before getting back into the gym, houser