I have been into intense strength training for about 2 years now. I train for 5 days a week with a healthy moderate calorie protein focused diet . My periods have always been regular, sometimes early and last for 4-5 days with average flow. Lately my mensural flow has reduced to 3 days and scanty( requires one sanitary pad a day). Could exercise be the cause ? Are my estrogen levels reduced due to weight training ? Please advice.