No reason I can see not to do it other than the fact that it will be hot. I think it is 11 miles long, all downhill, with a drop of, I think, 5000ft. A bit hard on the knees but if going on an organised excursion then you have many hours to complete it. You need to be able to complete it though as the boat from Ayia Roumelia at the bottom is the only way out (other than walking back up!).
Probably the best scenery I have ever seen.
I have read that you can organise it yourself (i.e. bus to Ormalos at the top, boat from Ayia Roumelia at the bottom, and then bus from Chora Skafion where the boat goes to) but have no experience of this. Maybe others have.
Good luck. Don't forget to take sufficient water and food.