Thoughts on Target Heart Rate?

[Jiffer]

I am now working with a nutritionist as well. He has me riding 6 days on trainer for one hour and one long ride (60 miles) on Saturdays. I have to stay under 130 max heart rate (zone 1 - ability to carry conversation). He went riding with me once (he is a cyclist too and works with a lot of teams), he set my pace at 12 mph and told me not to exceed it.

First of all, I find it very intriguing that you are riding 6 days a week. That sounds like a lot! But when you are riding at such a low intensity, I guess it's fine.

How did he determine your 130 max? Was it when he went riding with you and gauged how you did?