Ladies Only Please - Why Are Heavy Periods And Cramping Frowned Upon

When that time of month comes, I feel gratitude. I feel hope that when right time, and man comes, I can give life.

if I do biking and 15k walks during period, my period is light and almost non-existent

if I skip bike snd do less walk, then my period is heavier (not dangerous like in medical websites) and on first day I feel cramping and tiredness.
I can do things, but at slower speed

somehow I feel connected to Earth when period is slightly heavy (clots are a US quarter size) and I get uncomfortable cramping on the first day

is this wrong? Is it compulsory to do exercise to feel like period is almost non-existent?

 

Thank you