Interesting study on exercise and thyroid

January 21, 2011

I found this interesting, it seems to indicate that exercise reduces T3 and free

T3 in the blood yet makes tsh t4 etc rise? I wonder if it 's because exercise

helps T3 be used, or, whether like Ray Peat seems to say that it's because T3

production is stopped, or maybe it's a combo of both?

" RESULTS: The results of this study show that exercise performed at the

anaerobic threshold (70% of maximum heart rate, lactate level 4.59 ± 1.75

mmol/l) caused the most prominent changes in the amount of any hormone values.

While the rate of T4, fT4, and TSH continued to rise at 90% of maximum heart

rate, the rate of T3 and fT3 started to fall. CONCLUSIONS: Maximal aerobic

exercise greatly affects the level of circulating

thyroid hormones. "

Dr. Ray Peat: I'm not sure who introduced the term " aerobic " to describe the

state of anaerobic metabolism that develops during stressful exercise, but it

has had many harmful repercussions. In experiments, T3 production is stopped

very quickly by even " sub-aerobic " exercise, probably becaue of the combination

of a decrease of blood glucose and an increase in free fatty acids. In a healthy

person, rest will tend to restore the normal level of T3, but there is evidence

that even very good athletes remain in a hypothyroid state even at rest. A

chronic increase of lactic acid and cortisol indicates that something is wrong.

The " slender muscles " of endurance runners are signs of a catabolic state, that

has been demonstrated even in the heart muscle. A slow heart beat very strongly

suggests hypothyroidism. Hypothyroid people, who are likely to produce lactic

acid even at rest, are especially susceptible to the harmful effects of

" aerobic " exercise. The good effect some people feel from exercise is probably

the result of raising the body temperature; a warm bath will do the same for

people with low body temperature.

chris

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