If we want to get better we have to read and learn as most doctors aren't the most knowledgeable to do so.
As Galathea has said, all our body is affected from head to toe if our thyroid hormones are low, and we can get other more serious diseases if our thyroid hormones aren't at an optimum level.
Most doctors believe that if our blood test results are anywhere in the 'normal' range that we are on sufficient. That's not true, we have to have a TSH around 1 or lower.
T4 (also called levothyroxine) is an inactive hormone and is also called levothyroxine (a synthetic hormone). Thyroxine is our 'normal healthy' hormone which travels round our body and converts into T3 (liothyronine) which is the active hormone required in order for us to function normally/healthily. This is the most important hormone.
Ask your doctor for a full thyroid function test (probably wont) TSH, T4, T3, Free T4, Free T3 and antibodies. If you can afford a private blood test for those the GP wont do, we have a list of recommended ones and you get a small discount.
At the same time ask for Vitamin B12, Vit D, iron, ferritin and folate too, we need these to be towards the top of the 'range'.
When we exercise before being on the optimum of hormones for our bodies, and as we are replacing the hormones daily, it reduces our T3 which might have an effect on how we feel.
Always get a print-out of your blood test results for your own records and post if you have a query. Make sure the ranges are also stated as labs differ.
Follow Galathea's very important and I copy:
When you go for you review, dont take meds for 24 hours before the lood test, dont eat on the morning of the test, get tested as early as possible and make sure you get all the results in writing.
Also food interferes with the uptake of thyroid hormones so your stomach should be empty and take levo with 1 glass of water when you get up and wait about an hour (new recommendation) before eating.
If you prefer, you can take your dose at bedtime, as long as you've last eaten about 2 to 2.5 hours previously.