Thursday, September 19, 2013

Menstrual cycle abnormalities in exercising women, including me.

So  much great information on HA is available in the medical literature.  it really is a shame that your average OB is not better educated.

My friend was recently told that she had less than a 50% chance of regaining cycles if she gained weight / cut exercise.  Way to pull a stat out of where the sun doesn't shine doctor!

Here's an article where they followed women with FHA for an average of eight! years.  The doctor counselled them on the advisability of gaining some weight and cutting exercise to help restore cycles and improve bone mass density.  70% of the women started cycling again.

Those 70% gained between 6.5 - 28 pounds.  Cycles were regained for the most part between years 1 and 2 of changes.  (Keep in mind that these were gradual changes and many of the women were on either HRT or birth control pills, with a break every 6 months or year to see if they were cycling).

Take a guess as to the weight change of the women who did not start cycling again.  Surprise surprise, either no change or a decrease of a pound or two.  Unfortunately they don't mention changes in exercise.

I also think that the cycles could have resumed more quickly had the weight gain / exercise changes been made in a shorter timeframe.  Most of these women were not trying to conceive at the time the study started, so had less incentive to restore cycles in a short timeframe.

This is another interesting article where three menstrual cycles were examined in either sedentary women, or "moderate exercisers".  (On average, running 20 miles per week plus 5 hours of other, nonspecified, exercise).

In the sedentary women, 91% of menstrual cycles were ovulatory, 9% (all in one woman) had a luteal phase defect.  In the exercising women, 45% were ovulatory, 43% had a luteal phase defect, and 12% were anovulatory.

There was no significant difference in energy availability between the ovulatory and LPD cycles in the exercising women (although both were lower than the sedentary women).  Again, though, I bet you can predict what the energy availability looked like in the anovulatory cycles... yup - MUCH lower.  These women had an average energy balance of about -1000 calories per day, and also ate only about 50% as much fat as the others.

So even in recreational exercisers who are cycling, the energy deficit can cause cycle issues.

Speaking of luteal phase (LP) defects, I now have four postpartum periods to compare in my own life.  In all three live birth cases, my first cycle was while still breastfeeding, but I weaned right around the time the second started.

After #1 was born my LPs were as follows (P = I used Prometrium 200mg 1x/day) (bmi 21.9):
4, 8, 7, 16P, BFP

After #2 (bmi 20.7):
6, 6, 7, 9, 9, 9, 10, 10, BFP [

After my mc (bmi 21):
7, 14P, 14P, 14P, 14P, 10, 12, 13P, 14P, 18P, 17P, 12

After #3 (bmi 20.3):
10, 10, 11, 12, 12, 12

Guess what the difference is after #3 when my LPs have been much better and gotten longer much more quickly - VERY LITTLE EXERCISE!

Now, I ride my bike maybe once a week and play ice hockey once a week.  A fair bit of walking bc of chasing after the kids, and I lift weights once in a blue moon.

After #1 and 2 were born I was playing hockey 2-3x/week, biking to/from work, and lifting weights 2x/week.

More food for thought.  Pun intended ;)

Sunday, September 15, 2013

Energy availability and exercise

I've been doing a lot of research for my upcoming book and have come across a lot of really fascinating information that is just not very well publicized.  So I'm going to take a little time out of writing every few days and share some of the info here.

The first article is this one:  Energy availability in athletes, by Anne Loucks et al.

So here are some of the tidbits from this article (it's a review, so they're other studies that are referenced. I have not read each individual study yet.)

In studies where men or women were in "room calorimeters" (basically a device where they truly can measure every scrap of energy that you're using), they found that exercise was NOT compensated for by an increase in hunger signals, which meant that it was extremely easy to operate with an "energy availability" that was too low to sustain normal physiological processes = reproductive system shut down and all the other negative effects of hypothalamic amenorrhea. This is because exercise actually produces a hunger suppressive signal.

They did note that there ARE some people for whom hunger signals increase with ongoing exercise, they called these "compensators" vs. those for whom hunger signals did not increase, "non-compensators".  This difference could partially explain the difference between women with similar BMI and exercise, one who menstruates and the other who does not - nothing overt, but one IS adequately fueling her body and exercise, and the other is not.

Also, the slowdown of physiological processes happens immediately when not enough energy is being consumed; in the same experiment, they showed that the resting energy expenditure was decreased by 90 cal a day when in an energy deficit. So one day of negative energy balance isn't going to throw everything off, but throw in three or four in a row, and you're not doing your body any favors.

It explains so much about why you have to over-feed to actually recover from what you've done to your body. All those systems that have been shut down have to ramp up again, and use more and more energy as they do - and reproduction comes last!. So keep on eating, and sitting on the couch!!! (or if you do exercise, don't rely on your hunger signals to compensate for that exercise, you probably need to eat more than you think to make up for it.)