Low TSH

[DlingWitit]

I'm a 62 yr-old male.  For over 6 years of blood works, my TSH (3rd Gen) number has consistently been <0.01 L.  My other blood work numbers are typically good--glucose, cholesterol, et cetera.

Several times over these years my doctor has noted this low TSH number and asked, "Do you feel tired?"  I have responded, "Yes, I feel like I have chronic fatigue."  I am active, a recreational cyclist, but with a life outside of this.  He only knows that I ride a bike.  My impression is that he attributes this tiredness to exercise and work.  There are other symptoms, but I have come to tolerate them along with this general malaise, e.g. getting up in the morning and still feeling tired.  

For the amount of exercise that I do, I would not expect the extent of fatigue that I have.  My stress levels at work and home are very tolerable.  I have a manageable work schedule and it's typically a 9-5, Mon-Fri thing.  I eat well-balanced meals--plenty of fruits and veggies--and average about 6-7 hours of sleep a night.  I don't drink alcohol or smoke, and I take vitamin supplements.  I'm not overweight and my weight has been fairly stable over the past 10 years--within 5-10 lbs.  I find it easier gaining weight than losing it.

After riding my bike a week ago, I succumbed to a level of exhaustion greater than usual.  On a scale of 1-10, the ride was a 7--I've done harder rides.  This exhaustion continued through the week until today.  There was no fever, illness or loss of appetite.  I just felt very blah.  I cut back my activity this past week so as to not overdo it.  On a scale of 1-10, it was a 4-5.  I got my usual sleep and made sure I ate healthy as usual.  My energy picked up, but nowhere near that of a month or two ago when I was riding even more.

Could my chronic fatigue be linked to this low TSH number?  If this low TSH number is something to be concerned about, why is my doctor playing it down?

[DlingWitit]

Thanks for the suggestions.

[Barb135]

As usual, gimel covered it well.  Along with the FT3 and FT4 tests that he recommended to determine actual thyroid levels, which is essential, in the absence of hyper symptoms, I'm going to stress vitamin B12, due to the fatigue.  A vitamin B12 deficiency can cause absolutely debilitating fatigue/exhaustion, and while it doesn't sound like yours is "advanced", it sounds like this could be an issue for you.

Do  make sure you get the other things gimel suggested, tested, as well, since there could be a combination of issues.

[DlingWitit]

Thanks for the response.  I'll look into this.  

[gimel]

TSH causes no symptoms.  TSH is a pituitary hormone that supposedly reflects the levels of the biologically active thyroid hormones, Free T3 and Free T4; however, it cannot be shown to correlate adequately with either.  much less with symptoms.  At best TSH is an indicator to be considered along with more important indicators such as symptoms, and also Free T3 and T4.  

Fatigue can be related to thyroid levels,but usually a thyroid patient would have other symptoms as well.  Do you notice other symptoms besides the fatigue?  Are you taking thyroid meds that have suppressed your TSH level?  If so, what med and dosage?

If you haven't been tested for Free T3 and Free T4 (not the same as Total T3 and T4), then you need to request those tests.  If the doctor resists, then you should insist on it and don't take no for an answer.  Free T3 is the most important because it largely regulates metabolism and many other body functions.  I would also suggest that you be tested for Vitamin D, B12, and ferritin.