Limbs will be numb and cold, which seems to be a symptom of hypoglycemia.
Do you feel dizzy and weak? Are you anemic?
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It feels a bit like hypoglycemia. But you should feel dizzy and weak first. ...
Does your coach have any suggestions? Do you exercise too much? Try to reduce the intensity of exercise.
Oh, and you are talking about flexible exercise. Try long-distance running, swimming and other endurance sports to see if there are the same symptoms.
Actually, the body is very complicated. You'd better see a professional doctor. You can only guess from the symptoms you describe here, and some symptoms may not be noticed by yourself. Not to mention that there are many symptoms that match one symptom.
PS: Anemia can't be good ... and you can't eat drugs indiscriminately. It depends on what anemia, iron deficiency or something you have.