macelroy wrote:
> Maybe we agree then.
that's not *exactly* what i meant, but i'll let it go. maybe it's just
me, but i would never advise someone to lose enough weight that they
stop having their period. i pasted in a case study at the end of this
post, with an emphasis on the bit-
"Even though this particular athlete’s body fat percentage increased
with the intervention, there are plenty of females with low body fat who
retain their monthly cycle. There is no “set” level of body fat that is
applicable to all athletes for normal menstrual function."
so i think broadcasting over the internet that all women should try to
be between 5-8% bodyfat to achieve peak performance is a little
irresponsible. maybe they'll be ok, but maybe not.
h
http://www.usaswimming.org/USASWeb/...=395&Alias=Rainbow&Lang=en&mid=614&ItemId=531
A 19-year-old runner underwent a 15-week diet and training intervention.
She began menstruating at the age of 12, but had lost close to 20 lbs
over 3 months during her freshman year at college and had been
amenorrheic for 14 consecutive months leading up to the intervention.
Six months before the treatment, she began to complain of chronic
fatigue, poor performance, and a high frequency of illness and injury.
The dietary component of the intervention consisted of adding one 11-oz
serving of nutritionally balanced sports nutrition shake to her daily
diet. The training component of the intervention consisted of
eliminating one day of training from her schedule, bringing the
athlete’s program from 7 days/week to 6.
Results
* Prior to the intervention, this runner was deficient in her
caloric intake by about 155 kcal/day, or 1,085 kcal/week.
* At the end of 15 weeks, she gained 6 lbs and her percent body fat
was restored from 8.2% to 14.4%.
* Her LH levels increased to match those of her normally
menstruating teammates’.
* Her serum cortisol, which was 70% above the expected limit at the
onset of the intervention, fell significantly to only 21% above the
normal range. (Note: Cortisol is a substance the body produces in
response to both physical and emotional stress.)
* This runner’s performance improved during the season. She went on
to set more personal records than during any prior season, breaking two
school records and qualifying for Nationals in several events.
* She resumed normal menstruation three months later and has
displayed normal function for two consecutive months.
Implications
* Even seemingly small amounts of weight loss can impact
performance and health. The caloric deficit this runner was experiencing
would have led her to continue losing weight at a rate of approximately
1 pound every three weeks. This amount does not seem very high, yet the
effects on performance and health at this level competition were
significant.
* Intervention can be easy. One easily-accessible energy drink per
day and one rest day per week to restore the performance and
reproductive health of a competitive athlete…a simple opportunity with a
big pay-off.
* Energy availability is the key. Even though this particular
athlete’s body fat percentage increased with the intervention, there are
plenty of females with low body fat who retain their monthly cycle.
There is no “set” level of body fat that is applicable to all athletes
for normal menstrual function.
* It may take as long as three months for an amenorrheic athlete to
experience restoration of normal menstrual function. Time may vary
depending on the athlete and the severity of the situation. Patience and
persistence are highly recommended.