Hello Silencer. I’m not sprinter but a marathoner. Well. I have the same syndrome as you. It was detected before 4-5 years and I am taking T4 everyday. When someone has Hashimoto, he will be have it for the rest of his life. The dose of the thryrormone that you need it depends by the levels of the antibodies T4/T3/TSH you have and the condition of your Thyroid. My sister has the same as me and you. She was started with 24mg T4 a day and now after 5 years she is taking 120mg/day. I dont have so much problem. I started with 12mg and I am taking the same dose today. It depends by the body. My body condition is the same, full normaly except when I 'm stopping taking T4. I have stoped 2-3 times and I had a small problem in my weight (aprox. 3-4 kilos in 2 weeks). My sister is talking the treatment but she has taken about 15 kilos in 5 years. After I started the T4 I have not any problem except a small problem with my night-sleep but I can’t be sure that it is from the hypothyroid.
Hypothyroidism is not a big problem if you are checking it casual. Personaly I 'm doing blood test every 3-4 months to check T4/T3/TSH/SGOT/SGPT.
Of course you have to talk with an endocrinologist to set your dose!