so i just started my ec stack this morning 25mg ephederine 200mg caffeine,so i start my 5 min warmup then put the incline all the way up and start @ 3mph then after a bit bump it to 3.4 for a few then 3.2 then my heart rate had gotten up pass my target so i droped it down to 2.8 i got like 10 mins left til i hit 45 min all of a sudden i look @ my polar heartrate mont it sayz 155 then 161,170,178,185!!!!so i stoped rite away felt my chest my heart felt liek it was gonna come outa my chest!! has anyone else had this every happen to them ??? it freakin scared me i thought i was gonna have a heart attack....