Giggs, 39, was handed a start by United manager Sir Alex Ferguson on Tuesday night.
"You get yourself prepared for a big game, you get yourself up for it. Then afterwards you don't sleep or eat properly. So I'm still feeling the effects, really. That's probably what's changed a lot after turning 30, the actual recovery from games takes longer," Giggs told the Mail on Sunday.
"I think after a big European game you're looking at four or five days. For two days afterwards I don't really do anything. I do a recovery the next day, which is bike work, a light stretch, some yoga and an ice bath after that. Then the second day I would just do the bike again for 20 minutes and then do some strides, which is box to box, just eight of them, just to get the legs going and the blood going again."