Brief Answer:
Probably a vasovagal stimulation...

Detailed Answer:
Hi

Thanks for posting the query

Most likely this is a vaso-vagal reaction. One needs to tense their abdominal muscles and strain a bit during a bowel movement. This action stimulates the vagus nerve. A stimulated vagus nerve thus, slows the heart rate.

At the same time, when you tense your abdominal muscles, blood flow back to the heart decreases a bit. This results in a lower blood pressure.

The combination of a slower heart rate and lower blood pressure could make you feel lightheaded and weak.

Do not worry! This is a normal phenomenon which most of the individuals go through. If the weakness lasts long please consult your doctor for a complete evaluation.

Hope I have answered your query; I'll be available for the follow up queries.

Regards
Dr. Naveen Kumar N
ENT and Head & Neck Surgeon

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Brief Answer:
Please consult your physician/cardiologist...

Detailed Answer:
Hi

Thanks for writing back

I sincerely apologize for the delay in answering the query, due to my busy schedule.

I would suggest you to consult your physician/cardiologist and get a thorough evaluation done. You would require blood pressure to be checked in 3 different positions, an ECG and evaluation of the cardiac status. Also, you may require examination of blood to check for hemoglobin status and the stools for any occult bleeding.

Hope this clears your doubts. I wish you good health and good luck.

Regards
Dr. Naveen Kumar N.
ENT and Head & Neck Surgeon

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