Anxious people notice their heartbeats and often respond to a normal raise in beats with panic which make the heart race even more.
My heart got 'stuck' at 145 bpm. It started when I woke up at 2am and kept on going despite me lying down. It was still 145 when the ambulance got me into A&E at 6am. They tested my heart and bunged me some beta-blockers - which later triggered panic attacks because I was aware that my heart had
slowed right down.
Having scrutinized that night, I recall that I had a Chinese meal (lovely, but every time I had one, my heart would race - possibly MSG sensitivity) and a pint of 7% craft ale (That's some hefty stimulants right there)
It's a horrible feeling when your heart is going like the clappers (as if you're running) only you are lying down!
You have anxiety. You had a cigarette (stimulant) but here is where it gets confusing because you say 'bike' but that could mean motorbike or cycle to me. If it's a bicycle then you will naturally have elevated your heart rate through exercise, and being anxious, you will be more aware of sensations in your body, and more likely to react to them with panic which will make the heart beat even faster. Add to this, if you have a bit of a cold or raised temperature, your heart will beat faster - as it does when we are in pain or have just eaten a meal. This is completely normal, but it doesn't
feel normal, so we trigger the fight or flight response and that is like throwing fuel onto the fire - BOOM!
Anyway, I'm still here - four years later. No heart problems aside the usual anxiety symptoms..
All the best.