I agree with domlazz
(to a degree
).
If your only taking 0-1 days a week for recovery then look at your RHR as an average over all the days you worked out in a row. If you exceed that avg by 5 beats in any one-day then you should consider taking an extra day off the next day.
If your workouts vary on frequency
(you do them when you feel like it
) then you’re really out of luck on using your RHR as a means to determine when a rest day should occur. I'm not saying you can't use them but your more likely to see your RHR jump way up and down and will be harder to spot a bad trend vs. irregular training.
Weight training, in my opinion, does not count as a "training day"...unless of coarse you get your HR above 130 and keep it there for more than 25 min.
(which is possible btw
)
When to take RHR:
I don't recall who it was on here that suggested it, but I found it to be very, very, very true. Try to take your measurement as close to when you get up as possible everyday. I used to take mine while reading these posts, which happened to be after I was already to go to work in the mornings...it made for high inconsistent readings
(espicially after I read some of Bears comments
). Now, I get up, hit the bathroom, strap on the belt, lie back down, and wait to start my timer once my HR is below 60, and sleep for 5 more min. Presto...a nice RHR average over a 5 min period of time.
Lastly, these are just the views I've had from my short time working with my HR. You should simply start with taking your HR first thing in the morning and track it everyday to become your own best critic on how your body is reacting to what your putting it through.