Hi I'm 44 have been running a couple of years, between 5-10k at most, periods are much better because of it but my times/ willingness and feeling lethargic are all affected by hormones.
My last 2 periods have been very light in comparison to normal and I have had a few moments of going from fine to seriously overheating, with sweat dripping off me. I have also found that my body is struggling far more with my exercise. Could this be the start??