Re: Reverse T3 increases with prolonged exercised and decreased food consumption

[Guest guest]

Very good read this is a new one on me see we lean something new everyday.

Co-Moderator

Phil

> From: Barb <baba@...>

> Subject: Reverse T3 increases with prolonged exercised and

decreased food consumption

>

> Date: Monday, June 28, 2010, 1:19 PM

> or why eating less and exercising

> more doesn't work for many

>

> THE THYROID FUNCTION IN YOUNG MEN DURING PROLONGED EXERCISE

> AND THE EFFECT OF ENERGY AND SLEEP DEPRIVATION

>

> http://www3.interscience.wiley.com/journal/119531428/abstract

>

> Thyroid function has been investigated in 24 young military

> cadets participating in a 5 d ranger training course with

> heavy physical excercise, calorie deficiency and deprivation

> of sleep. The cadets were divided into three groups, each

> differing in the amount of sleep and food consumption. The

> serum levels of thyroid hormones (T4, FT4, T3, rT3) and TBG

> showed a biphasic pattern during the course. Initially there

> was an increased secretion concomitant with an increased

> deiodination of T4 to T3 and rT3 mainly due to physical

> exercise. When the activities lasted for several days

> without sufficient food supply the thyroid secretion

> decreased simultaneously with an alteration of the

> peripheral conversion of T4 to rT3 instead of T3. A

> significant correlation was found between the changes in

> total and free thyroxine (r= 0·9) and between the

> increase in rT3 and decrease in T3 (r= 0·6). TSH

> decreased during the first day of activities and remained

> low throughout the course. The TSH response to TRH

> stimulation was greatly reduced during the course due to

> physical exercise and calorie deficiency. The present

> investigation demonstrates that the thyroid function is

> strongly affected by prolonged physical exercise and a

> negative energy balance, whereas sleep deprivation does not

> have any significant influence. The results indicate that

> the alteration observed is not regulated just by the

> hypothalamo-pituarity-thyroid-axis alone.

>

>

>

> ------------------------------------

>

>