after doing so, watery or blood tinged dicharge can be due to several things ( ovulation, infection - but less likely if there are no fever, pelvic pain..-
but in your case, it is related to stress most probably..
to be on the safe side, you should consult a GYN to check for this..( ultrasound + blood tests)
1- it sounds like the trigger of your spotting is high-intensity exercise. When it comes to intense exercise, it is actually more common to have lighter periods or less frequent periods than it is to have spotting. However, spotting during very heavy exercise has been reported by some women. Either symptom, spotting or loss of periods, could be a sign that you are stressing your body too much. The bleeding itself is probably not dangerous, assuming it is only a small amount, but you could be causing damage to other parts of your body from exercising too much or too hard. I would recommend listening to what your body is telling you and try to cut back a little to see if the spotting goes away.
2-Also note that some women experience spotting during ovulation, so if you only notice the bleeding mid-cycle, this could be the cause.
YOU CAN TRY THE FOLLOWING:
1-make pregnancy test
2-TRY to decrease your woking out ,If the spotting does not improve with a lighter exercise regimen, I would recommend seeing a doctor for a full evaluation as Dr charafeddine said
NOTE :whenever you are working out and especially you are exercising a lot try to drink a lot and balance your diet ,dehydration may cause sometimes spotting