It should be fine. I made the mistake of regularly taking large doses of d-amp (up to 90mg+ adderall or 210+mg vyvanse) which allowed me to do cardio for up to 4-6 hours without rest. This eventually resulted in extreme palpatations and angina. The angina was worst, and actually felt like my heart was being pinched for up to a few weeks. I haven't done this in about 2 months and my heart finally is starting to feel normal again. I need to get an ecg done soon just to make sure that my heart is fine. Small amounts are fine, but don't let it become addicting. The euphoria that I would get from taking amps and exercising was indescribable, so I would continue to take more throughout my exercise. Don't make that mistake. 5 or 10mg would be absolutely fine to give you a boost, but be careful and stop immediately at the sign of any side effects. Also, take a stopwatch so you can monitor your pulse when you are at max. I realized that I was pushing my heart above 90% max on amps, and I feel that's what did the most damage.