Heart races on stimulants after meal

Usually after about an hour after taking my meds I notice my heart starts to race at like 130 bmp. I have been going nuts trying to figure out why. (Dehydration? Anxiety?). I usually take my meds with breakfast but today I didn’t and I noticed I didn’t have the racing heart rate! I ate a pastry and 20 mins later there it was. My heart beating out of my chest at 130bpm. It’s so uncomfortable. I’m trying to understand how and if the two could be related. Does anyone have any experience with this symptom?