32 years old. not overweight. started exercising again but i am struggling with dizziness. can hardly get my heart rate up before becoming dizzy. could low blood pressure be a problem?

Medical : Issues cannot be ruled out, but deconditioning is likely contributing as exercise should be gradual allowing for your heart and lungs to adjust for intensity. Having a general medical evaluation should help in ruling out possible medical causes.

Gradual + hydration: Start your exercise at a low intensity and gradually increase the intensity over days/weeks/months. Drink a couple of glasses of water before starting exercise to ensure proper hydration. Have a healthy diet, exercise 30 minutes/day, drink plenty of water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. For nutrition: http://www.choosemyplate.gov/.