Why can't I bend my head after hair transplant? My surgeon told me it's better not to.

The Internet is a source of good information but it may leave you with conflicting answers.I've never seen grafts popping from prayer or bending or while straining on the toilet pooping (Yes..the question has been asked).  Maybe it is possible.  It is always a good idea to follow your doctor's recommendations.

The reason/s why you shouldn't bend your head at least the 1st day post op so you will not cause grafts to pop out or an increase bleeding in the recipient area.  

Bending for the first few hours after a hair transplant might increase the pressure of head vessels and can potentially be harmful (no proof though).  However after the procedure and the day after that the grafts are tightly taken and cannot be dislodged by bending head.

You'll want to check with your surgeon if the bending you did caused any problems.In general, bending is not recommended because if increased pressure in the recipient area and increases the chance of the grafts coming out - a phenomenon called 'graft popping'However, there's a whole spectrum of bending from very slow short duration bending with minimal angle to fast, rapid succession acrobatic cartwheel-like flips. The former would be unlikely to cause much of a problem whereas the latter would almost certainly cause popping. You're wise to have stopped these movements as you've invested quite a great deal into the procedure to do anything that might compromise the result. If you're concerned, check in with your hair transplant surgeon. He or she can tell you if there are any problems that resulted from these movements.

Since your surgeons knows you, it would not be right for me to respond differently. Maybe your surgeon knows something you are not telling us here on the internet. 

Bending your head after transplant may cause traction in the donor wound and lead to scarring, so listen to your doctor.

Post op, we do not want excess pressure on the surgical site. For the recipient site, we do not want to force the grafts out of the slits and for the donor site, we do not want tension on the healing process.