Lately my resting heart rate has been between 45-55. is that normal when sitting? im 35. i run 2-3 times a week and i workout 4 times a week.

Yes : Hi, yes.. heart rate can be slower in people who work out as much as you do, be sure to be having a good diet and taking enough water, to rehydrate.

Slow rate: That resting heart rate in a wellconditioned young adult may be perfectly normal providing there are no symptoms like lightheadedness, weakness,fatigue, cold feelings or abnormally low or even high blood pressure. Just to be sure I recommend that you have an EKG to know that the rhythm is simply sinus bradycardia and not abnormal heart rhythm like heart block, av nodal or ectopic atrial rhythm.