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From:  "John Messmer, M.D." <jjm23@p...>
"John Messmer, M.D." <jjm23@p...>
Date:  Mon Jan 15, 2001  4:55 am
Subject:  Re: [vocalist] singing and health (and weight)


This issue comes up from time to time. I have been contemplating an answer
that will be accurate and not highly complex. Unfortunately the entire
subject requires a knowledge of embryology, physiology and histology.
Please understand that I do not say that to imply that the list members will
not be able to understand it, only that my ability to explain it may be
lacking.

The vocal folds undergo thickening under the influence of testosterone at
puberty. There is some growth for women also, but it is not in the same way
as in men. The larynx itself grows also in addition to the pharynx, jaws,
nasal passages and so on.

A woman's vocal folds and muscles maintain their structure under the
influence of her estrogen. Depending on the balance of estrogen and
progesterone, she has more or less variation throughout the menstrual cycle.
If she has "normal" weight, things cycle normally. Normal differs for every
woman. That is why some women have vocal problems at the menses and some do
not. Birth control pills can benefit, harm or have no effect depending on
the balance of hormones and how they are metabolized in her body. The
effect is similarly variable with hormone replacement after menopause.

The body weight affects how much estradiol (E2) is converted to estrone
(E3). E3 is longer lasting and very estrogenic in certain tissues. E2 is
converted to E3 in fat. The number of estrogen receptors in various tissues
is genetically mediated. A woman with a lot of estrone, a lot of estrogen
receptors on her vocal apparatus and low levels of progesterone will have an
entirely different type of effect from her weight than a thin woman with few
estrogen receptors. The fat also can convert adrenal intermediates into
androgen-like hormones or not depending on the woman's genetic makeup.

Some overweight women have polycystic ovary syndrome. In this situation,
she may have too much testosterone and other androgenic hormones.

If a woman has less than about 10 percent body fat, such as, through anorexi
a nervosa or other process, her E3 levels fall. There is feedback to the
hypothalamus and pituitary to reduce the surge of two hormones responsible
for stimulating ovulation (this is probably a survival feature to prevent
conception during a period of inadequate calories). The normal cycling is
inhibited allowing a reduction in estrogen due to lower pituitary
stimulation. The voice can be affected if it has not reached maturation
most likely, but unless she is at the point of malnutrition, if her voice is
formed, it will likely stay OK. This disregards the effects of estrogen
receptor levels.

There are so many ifs, ands and buts that there is no one correct answer to
the question of weight and hormones and singing. I will point out that fat
cells do not absorb testosterone or anything else besides fat.

Unfortunately, the complete explanation requires a lot more reading in
medicine and physiology. There are many aspects that are not even known due
to the extreme variability in E2, E3, progesterone and testosterone levels
in women.

I hope this shed some light on this complex issue.

John

John J. Messmer, M.D.
Assistant Professor, Family & Community Medicine
Penn State College of Medicine



  Replies Name/Email Yahoo! ID Date Size
8406 Re: singing and health (and weight) Reg Boyle   Mon  1/15/2001   2 KB
8407 Re: singing and health (and weight) Karen Mercedes   Mon  1/15/2001   4 KB

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