Riding a bike after FUE hair transplant?

It is best to ask your surgeon about post operative care as each doctor has their unique regimen. There would be no reason why you cannot ride a bike to work.

It is perfectly ok to ride your bike now as long as you are not going to sweat profusely.You can cover the area with a hat or scarf as long as you don't apply a lot of pressure to the grafts.

I personally would recommend you wear a handkerchief as you certainly don't want to let the perspiration accumulate with the grafts.  Sweat + crusting is not a good recipe.  That being said, it all depends on how many grafts were done and where they were placed.  When in doubt, remember, it is always a good idea to contact the office of the surgeon who performed your procedure as they may have different recommendations to help improve your post FUE outcome.  Best of luck! 

Light exercise at four days after your surgery is fine, moderate to heavy exercise should have a longer waiting time. The only concern would be wearing a helmet, which generally you should wait two weeks to do. A light hat or scarf so the sweat doesn't accumulate (or if you are able to ride calmly and mostly avoid sweating altogether) would be ideal. 

There is no handicap  to ride a bike . As it was mentioned below it is a good idea to cover your head with a hat or sport cap  but be sure that it is not making a pressure on the recipient area . Good luck 

You can ride a bike, run a marathon, lift weights, go to the gym or do anything you want at 4 days as nothing will go wrong