Why is exercise bad after FUE?

Yes you are right , blood  is good for implanted grafts . But  you should be carefull about do not make very hard exercise to increase blood pressure so much that may cause pop up of the implanted grafts and do not hit your head to any where.

After 4 days, you can do whatever you want except for scuba diving. Full exercises is just fine even running a marathon if you want to