Last year, Clove wrote a couple of informative posts (see here and here) about the nuts and bolts of the menstrual cycle and how it can affect your running. Today I’m adding to this conversation by asking the question: can your menstrual cycle cause or worsen injuries?
A few days ago, cooling down after an innocuous 4-mile run, I felt the niggly nagging of my left posterior tibial tendon (my version of the Achilles heel) telling me it wasn’t happy. Now if you’ve ever read my training logs you know I have struggled with this injury for quite some time, but over the past few months it has been feeling much better and I’ve been able to string together a reasonably healthy block of training. However, it does still bother me intermittently and I’m always trying to figure out the triggers. So when I got home I looked through my training log to check out the previous few days and compare them to what I was doing when last it bothered me. Sure enough, just about a month earlier I had a few days of unprovoked soreness…..and wait a second, a few days of soreness just about a month before that…..and again a month before that. Coinciding each time with the few days before getting my period. Which made me wonder, was I falling victim to some strange variant of PMS?
When I turned to the medical literature to try to figure this out, I found a fairly extensive body of work devoted to studying the role of sex hormones (which circulate in high levels around the time you get your period) in soft tissue injuries in women. All the studies I looked at made reference to the fact that women suffer more tendon and ligament injuries than men, and the hormone estrogen, in particular, has been implicated as a potential contributor to this. In one study, higher levels of estrogen interfered with the ability of women’s knee tendons to regenerate after exercise. This is because the body can’t make new collagen well when estrogen levels are high, and collagen is one of the primary ingredients in our soft tissues. Another study demonstrated a similar finding in women on oral contraceptive pills (OCPs, most of which contain the two female sex hormones estrogen and progesterone); women who took OCPs did not regenerate collagen as well as those who did not.
Several studies (see here and here) even specifically examined how the hormonal fluctuations of your period cycle can affect the ability of your tendons to recover and heal after bouts of exercise. Estrogen is very high during the “luteal phase” of the menstrual cycle, which is the last week before you actually get your period, so the authors of these studies hypothesized that women’s tendons would not heal as well during this time of their cycle. However, this did not turn out to be the case; like the prior studies I cited, in these two studies women’s tendons did not recover from exercise as well as men’s, but this was true regardless of what stage of the menstrual cycle a given woman was currently in when she was studied.
Of particular interest to me was one other study that actually checked to see if there are estrogen receptors in posterior tibial tendon tissue (there are in ACL tissue), and whether there are increased numbers of these receptors in tissue from male and female patients with posterior tibial tendinitis. If so, this would suggest that estrogen is more active in diseased tissue in this condition. Lo and behold, there are estrogen receptors expressed there, but the numbers are no different in men versus women, or in those with diseased tendons versus those with healthy tendons.
So can I blame my monthly posterior tibial tendinitis flares on PMS? I certainly would like to – it beats blaming it on my running!
Have you ever noticed any funky flares of soft tissue injuries around the time of your period? How else has your period negatively affected your training?