First of all, keep in mind that I am unable to diagnose you because I am unable to examine you, this forum is for educational purposes.
It is not normal to see a 'throbbing pulse' in the palm of your hand. It is possible that you have an abnormal artery at this location that causes this symptom. I do not think this is related to 'adrenalin', because this should affect everything equally not just the palm of your left hand. I would suggest that you get screened for hypertension and a possible sleep study (most adults do not require a nap during the day-and this may be a sign of sleep apnea). I would also see a vascular specialist to get and ultrasound of your left palm to see if the sensation that you describe is really a pulse.
I hope this has been helpful.
That is the strangest thing I have heard in a while, have you discussed this problem with your PCP. Sounds to me there may be some inflamation issues or nerve problems that could be causing this. Good luck to you!
When I woke up this morning I noticed the same thing in the palm of my left hand.