I am 28 years old, male, 5"11 170 lbs 11-13% body fat.

I have mild hypothyroidism, but it's likely temporary and self induced, no medical cause was ever found and it was likely brought on by over training and and under eating a few years ago. It's actually a lot better now that i am eating around 3.1k calories a day and its been coming closer to being right since i started eating more just a few months ago. My most recent thyroid tests are TSH, which was 5.2 (range 0.5 - 4.5) so i am only just outside of the range now, it was significantly worse before when i was under eating and over training. My Free T4 result is 16.7 (range 11-22) which is perfectly normal. I should also mention that i have no symptoms of hypothyroidism though i did have a few in the past when i wasn't eating much, i've also been incorrected treated for hypothyroidism with T4 meds in the past, i no longer take them.

In general i feel in good health, apart from a slightly diminished libido and lack of morning wood.

I've had two lots of blood tests 6 weeks apart, today i got the latest results, this is for testosterone because i never wake up with morning wood. However I did find that while on a two week break from all exercise, my morning wood returned every day without fail.

April result
Total Testosterone: 19
Free Testosterone: 45
Sex hormone binding globulin: 42

June 14th 2013 result
Total Testosterone: 20 (range 9-27)
Free Testosterone: 42 (range 35 - 92)
Sex hormone binding globulin: 46.6 (range 16.5 - 56)

I was doing regular exercise (weights, sprinting) prior to both of these tests. Free T is on the low side and SHBG is raised. I've been trying to figure out what is causing this. From my own experience it's almost always the simple things, so the most likely causes i can think of is that i am over exercising (possibly overtraining) or i am under eating, or both.

I found a study where higher levels of SHBG were associated with overreaching during strenuous military training. I can't post links, but google this and you will see it. Serum sex hormone-binding globulin and cortisol concentrations are associated with overreaching during strenuous military training

I do a 4 day split, monday chest, tuesday sprints, wednesday back, thursday shoulders, friday arms, saturday sprints, sunday rest. I also do abs at the end of most weights workouts (about 4 times a week for 15 minutes a time) and my sprint days consist of 5 or 6 sets of all out 100m sprints. I have also recently started doing yoga once a week, which i find to be quite resource taxing on the body.

I eat around 3100 calories a day, roughly 48% carbs, 30% fat, 22% protein. My weight isn't really going up or down and that may indicate that i am not eating enough food for my exercise level.

I'm just not sure what to do so i'm looking for any help i can get. My present plan is to just stop all exercise for 6 weeks and then have my bloods taken again and see if the problem has been fixed. I'll also get to see if my morning wood comes back again.

If everything does come right, i'm still going to be at a loss because i want to keep exercise in my life without the negative hormonal affects may be occurring from it. I just don't know how much exercise to do, what the right balance is.