How much exercise can I give my 1yr Whippet?

My young Whippet Darcy is very energetic. How much lead & free running could he have per day? I don't want to over do it as he is very leggy & has a narrow chest also long back.

Thanks in advance. Look forward to hearing from you.

Might be worth checking the post I put on about my one year old retreiver, some good points made.

I also had a lurcher a couple of years ago and boy did she have so much energy- however as she had a steal rod in her broken leg I had to watch her sprinting. The thing is I would say with the type of dog like this it would go and go and go as in nature to get the end result? Only a comment as I am not a professional

Thanks Bella will check your post. I also had a Lurcher but he was nowhere as mad as my Whippets. Also it's his confirmation that concerns me. Good luck with your retreiver.