Levothyroxine (T4) Improved My Max Heart Rate and Anemia

[kcrunner]

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My doctor put me on levothyroxine 75 mcg back in January.   At the time I went in my TSH was 5.7, I was anemic with a HCT of 37.5%, and my testosterone levels were 306 ng/dl Total with 6.1 ng/dl free.

I am an avid runner / cyclist that strength trains regularly so my body fat percentage is never high (5 to 9%) and I eat a whole foods diet that is rich in fruits, vegetables and lean meats / cold water fish.   

My doctor had me back in to check my levels last week.   In 5 weeks my TSH had dropped to 3.9, I am no longer anemic with an HCT of 41.4%.   I am still awaiting my latest testosterone numbers but given how much better I feel I would suspect they have improved as well.

A noticeable metric in my performance since starting levothyroxine has been my average heart rate and peak heart rate when training.   Previously on a hard core ride on the trainer (it was winter so more rides were on the trainer than outside), my heart rate would spike as high as 185 to 190.   With the same level of effort, my heart rate now spikes to 170 or so.   On hard runs my average heart rate would be over 150 while at a faster pace than before its averaging in the low 140s.   My recovery rates have improved a lot as well and I am seeing a difference in the weight room.

So anyway let your doctor put you on synthyroid and see what your results are in a month or two.  You might find it makes a big difference.

[PeakT]

Interesting story about the max heart rate.  I guess you have to work harder to get the same oxygen intake or something (regarding the higher heart rate).

And I didn't know that thyroid meds could improve anemia?  I've never researched that.  I guess if you increase testosterone that should help.  Or is there some other mechanism?  Don't have time to look it up right now...

[kcrunner]

I am pretty sure that anemia was why my heart rate was higher to maintain a given level of effort.   I know that anemia many times correlates with hypothyroid.   However, I am not sure if that is because it also tends to also correlate with low testosterone.   I am hoping to get my hematocrit levels a little higher in the next few weeks before the spring race season gets into full swing so I am taking an iron supplement to see if that helps. 

Should have my latest testosterone levels back tomorrow.  Considering how I feel, I am assuming they will be higher than they were back in January. 

[PeakT]

I am pretty sure that anemia was why my heart rate was higher to maintain a given level of effort.   I know that anemia many times correlates with hypothyroid.   However, I am not sure if that is because it also tends to also correlate with low testosterone.   I am hoping to get my hematocrit levels a little higher in the next few weeks before the spring race season gets into full swing so I am taking an iron supplement to see if that helps. 

Should have my latest testosterone levels back tomorrow.  Considering how I feel, I am assuming they will be higher than they were back in January.

Well, this couldn't be clearer:

http://europepmc.org/abstract/med/1099360

"Thyroid hormones generally stimulate erythropoiesis. These agents also increase erythrocyte 2,3-DPG concentrations, which serve to enhance the delivery of oxygen to tissues. In the absence of thyroid hormones, anemia frequently develops and may be normocytic, hypochromic-microcytic, or macrocytic. Anemia is an uncommon finding in hyperthyroidism but when present may be morphologically similar to that observed in hypothyroidism. Pernicious anemia has been strongly associated with hypothyroidism, hyperthyroidism, and thyroiditis. Complete correction of anemia often requires restoration of thyroid function as well as specific hematinic therapy. Continued attention to hematologic status is essential in the management of patients with thyroid diseases"