Today I met a girl who, because of her extreme athleticism, does not menstruate. She says she never has, and she has the physical appearance of a boy in her early teens, despite being 18 years old.
This leads me to wonder: are there any long term health benefits/detriments to being so physically active that puberty is delayed? Does it affect fertility, bone density, or anything else? What happens to a girl who stops her exercise program?
don’t know
I have heard that for women who enter such strict exercise programs after their 1st menstration and their period stops, when they stop the exercise, the periods come back. I’m not sure what happens when the 1st one never came.
I was taught that the above is the body’s response to extreme stress, allowing all energy to be devoted to survival.
Gymnasts have stunted growth due to their extreme activity. I dont think they recover from it fully once they stop- bone growth is halted during a crucial period. Not sure bout puberty changes though. I would imagine that an extreme excercise regime would change your body chemistry enough to delay puberty, but 18 seems old.
IIRC, body fat percentage has to be at a certain level for women to menstruate. Female atheletes at the Olympic level of effort often have body fat percentage that is comparable to male atheletes.
I remember a classmate who trained both in gymnastics and track. She was quite prepubescent-looking despite being 16; most of the girls in our school started puberty around 10-12. Then at the end of our junior year, she injured herself in track and took the summer off from exercise to let it heal. When we started our senior year, she was stacked! (And quite well-rounded, too. 
) Puberty caught up with a vengence! She could no longer do balance beam, her specialty. And since she’d never worn a functional bra (just “training bras”), she hated wearing a “real” one, which interfered with her running.
That’s correct. Many ballerinas in the post-Balachine era (he called for the extremely thin physique in modern ballet) never menstruate because of essentially no fat in their bodies. This is also why there is some truth to the old wives’ tale that breastfeeding is effective contraception; in poorer countries where most of the nutritution is going to the nursing baby, the mom will not begin to menstruate again.
This is a complex and all too common issue.
Excessive exercise can lead to delayed acquisition of so-called ‘secondary sexual characteristics’ (breast enlargement, menstruation, pubic hair, etc.). It is a matter of semantics whether this is equivalent to ‘delayed puberty’. In part, it is reasonable to look at this as delayed manifestations of puberty.
What happens: The effect of exercise is to “stress” the system. This leads to less estrogen (female hormone) being produced (the mechanism of ‘stress’-associated decreased estrogen production has to do with the hypothalamus, a structure deep in the brain. The hypothalamus, which controls essentially all hormonal, and zillions of other bodily functions, is designed to turn off the stimulus for estrogen production when the body is under stress. On an evolutionary scale, this makes sense because if a woman is stressed or starving, it’s not a good time to have kids.)
Concurrently, the exercise diminishes the amount of body fat which, in turn, diminishes estrogen levels (estrogen is made in fat tissues as well as the ovaries). The net effect is to cause very low estrogen levels.
Having low estrogen levels, especially at a time when they should be high, and should be building up a woman’s bones, does predispose to osteoporosis. This effect is heightened in women/girls who aren’t eating well (eg. anorexia nervosa - often associated with over zealous exercise). In those individuals, not only does the exercise lead to low estrogen and thus thin bones, but their limited calcium intake also promotes osteoporosis.
I will close by noting that the regulation of puberty, its onset and timing, is still much of a mystery.
I’ve also known girls who had delayed menstruation due to being overweight - I knew one girl who didn’t have her first period until she was 17, who was overweight, and have known a couple of women who said that their periods got very irregular when they got over a certain weight.
The cover story of this week’s Time is about the opposite problem – girls entering puberty early.
One of the possible factors listed was body fat – there are a lot more overweight kids nowadays. Specifically, the article cites a study that found that overweight girls tend to enter puberty a bit earlier than girls of “normal” or low weight.
May be TMI here, but…
My wife is a former anorexic, and did not menstrurate until about the age of 21. Occasionally, when her weight fell, she wouldn’t have her periods again–she has only had regular periods for the last four years. Lack of body fat was obviously a factor with her; her “cut-off weight” is 7 stone (98 pounds–she’s 5’ 4"). Fortunately in the last four years she has made a remarkable recovery, and now few people would guess she had problems for so long (and she is now quite happy to talk to people about it–else I wouldn’t be posting this).
Anyway, regarding the OP, it is possible that a woman will have health problems with delayed menstruation–my wife has been warned particularly about osteoporosis. Fertility is not a problem in her case, fortunately, but it can be. Most former anorexics are able to have children. I’m glad that my wife hasn’t been physically damaged by her experience–the mental damage she has had to face has been terrible enough.
To expand upon, and slightly disagree with, what KarlGauss posted:
While much of what triggers puberty is not known, it is becoming increasingly clear that leptin secreted by the body’s total fat mass acts as one (perhaps of several) signal to the hypothalamus to begin the pulsatile secretion of gonadotropin releasing hormone which leads to increased production of gonadotropins (gonado= pertaining to ovaries & testes; tropin = stimulatory hormone) from the pituitary. These in turn act upon the ovaries or testes to produce the rising levels of estrogen & progesterone or testosterone seen in puberty.
If puberty is truly delayed in 14-18 year old girls solely because of delayed acquistion of the necessary fat mass, puberty proceeds normally, the pubertal growth spurt results in the predicted final adult height, and the girl would not be at risk for osteoporosis.
If puberty is suppressed by high cortisol levels associated with anorexia nervosa or high levels of stress, the high cortisol levels will also suppress growth hormone secretion, cause early closure of the growth plates in long bones, limiting future growth, and result in a high risk for future osteoporosis.
For all practical purposes, it is impossible to distinguish delayed vs. suppressed puberty, and so any girl showing no signs of puberty by age 13-14 (breast budding, pubic/axillary hair growth) should undergo an evaluation
for a medical reason. For most girls, the future costs of continuing the high-intensity training and stringent dietary regimen outweigh the “gains” of staying in the program only to watch their former friends from gymnastics, ballet, skating, etc. win their gold medals or find glory in a professional ballet troupe, but it’s hard to convince girls and their parents of that.
gigi posts:
Not quite true.
Breastfeeding causes the pituitary to secrete higher than normal levels of a hormone called prolactin to stimulate lactation. High prolactin levels inhibit both release of pituitary gonadotropins (hormones that stimulate the ovaries) and the effect that those hormones have upon the ovaries. This often prevents ovulation and may prevent menstruation.
NOTE: Prolactin levels steadily fall even with continued breastfeeding, and may never fully inhibit ovulation. Women who are breastfeeding and having unprotected intercourse will have lower pregnancy rates than women who are not breastfeeding and who are having unprotected intercourse, but can and often do become pregnant. It is possible to show up pregnant at your 6 week post-partum checkup. It is quite possible for the first ovulation to precede the first menstruation after a baby is born, whether or not one is breastfeeding. Do not rely upon breastfeeding for contraception unless you actually do want a baby in 9 months.
OTOH, I would not call the reduced pregnancy rate with breastfeeding an old wives’ tale, either. It’s a quite well-established scientific fact. The keyword is “reduced”, not non-existant.