I've Always Exercised Regularly Running 3-4 Times Per Week 3-4

I've always exercised regularly running 3-4 times per week 3-4 miles, lifting twice a week and playing racquetball once per week. Last month I became severely dehydrated which caused my heart rate to drop severely, 78/34. After being put on an IV a recovered and my EKG at the hospital was normal. Since then I've been unable to run more than a minute or two without my legs cramping or my chest getting tight. I'm 53 and female. Should I have a heart workup even though everything showed normal?