Nature Calls during Meditation

I understand there are discomforts during meditation. Your body is fighting to stay in control, hence your legs fall asleep, you feel slight back strain, etc, etc.

The best way to deal with these discomforts is face them, hence meditation is actually a grueling, and rigorous exercise.

But what to do when nature calls (have to use restroom)? The body has to release itself of toxins, but then meditation gets interrupted.

How to handle this, especially when meditating early morning? I do 5 minute bike, few rounds of Surya Namaskar, followed by 30 min meditation.

Nature Calls during Meditation