I'm a nursing student, and have recently noticed that sometimes my pulse will skip every 3 to 5th beat.  I've noticed this on three different occasions, all 3 to 4 hours after having one large cup of coffee.  (I did not notice it right after the cup of coffee).  

I like to move around and get my heart rate up, because that makes it go away.  I feel like the lower my pulse gets (as low as 44), the more it skips.  It never does this when my pulse is above normal (above 65).  I usually hoover between 55-65 pulse)

I suspect that the coffee and my stress with nursing school (and fretting about this) maybe contributing.

I've noticed what I think is somewhat of a palpitation in my chest, actually feeling my heart skip a beat, but that's not what initially troubled me.  This all came about through discovery of checking my pulse and noticing it absent ever 3 or 4 beats, but continued on like clock work.  Today I counted that my radial pulse absence didn't occur until the 5 and sometimes 8th beat. But again, this was all noticed in my radial pulse, which I check religiously, during lecture to pass the time.

I'm 29, 6 ft, 168 lbs.

I run more than 20 miles per week, doing 2 miles under 8 min per mile, or 13 mile runs around 10 min per mile.  At rest, my pulse is under 60, sometimes as low as 45.  That said, i think heart rate is partially genetic.  My mother, who died of breast cancer at age 53, was a smoker, and wasn't the healthiest, had a low BP and heart rate.

Do I possibly have First degree heart block, or is this more a stress coffee thing?

Thanks,

PRC