Thanks.
I thought it was the Sympathetic Nervous system that raised your heart rate (accelerator) and the para was the brakes?
Yea I've been reading all up on ANS and all that jazz. Actually got interested in HRV (heart rate variability) for exercise purposes and then started to learn of its importance in overall human health, rMSSD, SDNN, High frequency, low frequency HRV. Cool thing is you can actually measure all this stuff with a basic heart strap and a phone app. But not diagnostic like a autonomic test you would get at a research hospital.
Some interesting stuff.
Yea I just wondered about the night time thing cause I can get them in the late night and early morning times when they state that is the time you cortisol levels are at there highest.
It's probably a lot more complex than just adding adrenaline. There's probably a lot of other biochemistry. I know for sure that your brain will increase parasympathetic tone to increase your heart rate with exercise, higher body temp, food in your stomach, etc...
so in other words, your equation is
extra beats=more adrenaline
When it's actually a lot more complex than this
extra beats=more adrenaline+parasympathetic tone+sympathetic tone+enhanced automaticity+all the other endocrine issues
Think about a heart transplant patient. All the nerves going into their new heart are cut. The brain can no longer control its rate. The heart will default to it's internal pacing which is about 100 beats per minute coming off the SA node. Any increase in rate is completely based on endocrine (adrenaline, cortisol, etc). However, over time, some transplant patients will have these nerves grow back. It's called Reinnervation.
Anecdotally I am aware of heart transplant patients who have confirmed reinnervation. They also report an increase in extra beats. Interesting to say the least, would make for a great scientific study!!
Personally I think this part of the nervous system can play a large role in extra beats. It's called the Autonomic Nervous System (ANS). Your heart rate from exercise is probably responding to these signals before it ever sees an increase in adrenaline, but I'm guessing.
I don't have an answer for your adrenaline-at-night question, I haven't run across that in my travels.