40%heart rate

The rate had gone up and was 45 to 50 but is down to 40% what should I do.

[Jerry_NJ]

I do not understand what you are asking.

But, I can say a resting heart rate of 45 to 50 is not necessarily bad.  If you do not have any problems/symptoms then that is a good resting HR for you.  Most of us have a resting HR over 60, but some have a very strong cardiovascular system and we don't need that many pumps to maintain bodily functions.  Some of those so "blessed" are great endurance athlete, such as marathon runners.

Now for the 40% part of you input.  I do not know what the 40% refers to.  Are you saying a HR of 45 is down 40% from your normal HR?  Rest HR assumed.