How does hormonal contraception affect the athlete? (Part 2)
It's been some Friday since we came up with the first part of an article on hormonal contraception in women who play sports. If you haven't reached it yet, or if you've forgotten all the information since then, it's high time you read it (again) here.
At the end, we mentioned that we would look at:
how HA affects aerobic / endurance training
how HA affects anaerobic / strength training
positive and negative HA
any scientifically based recommendations for HA
So let's get on with it.
Influence of hormonal contraception on aerobic and anaerobic activity
Several studies have found that hormonal contraceptives can affect performance, both endurance (aerobic) and strength (anaerobic). The point is, however, that the vast majority of studies were performed only on oral hormonal contraception (ie not on, for example, the hormonal intrauterine device) and, moreover, many of those studies do not respect the diversity of contraceptives at all - e.g. I do not understand why gestagen and combined contraception occur in the same group of test subjects. As we know from the last article, these two types of contraception behave very differently in the body. Or, for example, in one group of test people, women who train regularly mix with those who don't move that much. And to make matters worse, there is not much data on the subject of contraceptive athletes. And then for one to come up with some calm conclusion…
Aerobic / endurance activity
Endurance performance is affected by several factors, the three main ones being:
VO2 max (which is, in layman's terms, an indicator of your condition; the higher this number, the better off you are with the physicist)
lactate threshold (represents a specific measure of effort or pace at which fatigue begins to accelerate)
muscle efficiency
Hormonal contraception can potentially affect each of these measures, but not only that.
In order not to include you here in meaningless numbers, let us present the results of various studies on examples.
VO2 max is an indicator that is important for endurance athletes. Several studies indicate that the use of hormonal contraception is associated with a significant reduction in VO2 max, up to 5-15%. So if we imagine a top runner who starts taking contraception, it is a huge impact on her performance.
Overview of the results of individual studies or Milada, Josefín, Alžběta and Andrea, our endurance athletes, decided to start using contraception. What happened?
Milada with HA with first-generation progestins got tired as fast as she had on a treadmill as before, when she wasn't taking contraception; after 6 months of use, however, she found a 7-8% reduction in VO2 max
Josefína with HA without further determination (yes, such studies also exist) while riding a bicycle simulator found that she has a statistically significant reduction in VO2 max and lactate threshold compared to the period without contraception, although she did not notice any difference in performance; in addition, VO2 max was 3-6% lower during the 21 days she took the pills, compared to a week of placebo / no pills
Elizabeth with HA with third-generation progestins using it for 1.5 years showed no change in aerobic parameters compared to Andrei, who did not use any hormonal contraception; In addition, Andrea found a 7.5% increase in VO2 max in 6 months of training
After collecting data from all studies and knowledge to date on this topic, we can say that there is a fairly clear pattern: HA reduces VO2max, although this does not necessarily have an impact on performance. However, for top athletes, even a minimal reduction in VO2max can worsen overall performance, so HA use should be considered. However, HA with third-generation progestins should have less impact than HA with first-generation progestins or three-phase HA.
Anaerobic / force activity
There is a review that looked at 10 studies that discussed this topic. What about women using hormonal contraception and their strength compared to women who do not take contraception? Some studies showed an increase in strength, others a decrease, and the rest showed no change. Phew. However, as in the previous case with aerobic activity: each of those studies was quite poorly constructed.
One small study compared women who took HA with second- or third-generation progestins for min. 6 months for leg strength during three different times during the cycle. No change was observed, indicating that the androgenicity of HA (ie different generations of HA) ultimately had no effect. However, the group of women who do not use HA was not included, so we lack data for comparison.
Another study looked at women who did not exercise but had used HA for at least 1 year, or who had never used it. They completed 2 strength training sessions and 2 high-intensity aerobic workouts for 10 weeks. Result? No difference in strength or endurance was observed, there was no difference in the improvement of the two groups, however, the group of women who never used HA gained some muscle mass and lost a small amount of body fat.
These two small studies are just two raised drops in the sea. Two imperfect drops in a sea of mini-ponds of even more imperfect studies.
Based on these findings (and the recommendations from the first article), you can try to choose a lesser evil, but at the same time it is necessary to monitor what changes begin to happen after using / discontinuing contraception and whether we are OK with these changes.
Positive and negative HA
you have control over your pregnancy
you have control over the cycle
you usually don't experience PMS with it (at least not in such a style as without HA)
your risk of anemia is lower
potentially you run the risk of knee injury less
every woman has a different one, contraceptives have a different effect on each one
may have a negative effect on weight or body composition
potential negative effect on acute and long-lasting on some types of training
we still lack proper research on this topic, we still don't really know exactly how HA affects us
So what, should I take the contraceptive or not?
see the section above and consider the pros and cons; if you are a top athlete, it is best to avoid HA
if you are not allergic to synthetic estrogen, be sure not to take gestagen contraception; Athletes report more negative / side effects with this type of contraception compared to combined HA
if possible, avoid three-phase HA; of all studied HA they show the worst side effects (gain, impaired aerobic and possibly anaerobic performance, potentially worse gains)
Although HA with 4th generation progestins show benefits “for everyday life” (prescribed against acne, prevents water retention), due to their anti-androgenic effects they could logically have a negative impact on performance or adaptation to training (reduce overall and free testosterone and blocks the receptor without sending any positive signal to skeletal muscle)
HA with 2nd or 3rd generation progestins seem to be the best choice (well, behind the option of "not taking HA at all"), but it is not possible to specifically recommend which one to choose - there is not enough data on which to build nicely.
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