I have been doing a bit of reading about the role of the SNS in relation to insulin, weight loss and dopamine. This blog post and the one she links to in Calories Proper are of particular interest to me. Woo implies SNS dysfunction is central to the development of obesity, which in turn affects insulin and dopamine: http://itsthewooo.blogspot.com/2014/03/most-obesities-feature-sympathetic.html?m=1. What I am curious about in relation to these factors is whether measuring one’s HRV (which reflects the state of your nervous system based on heart rate patterns) would give you an indication if you are in weight loss mode vs. storage mode. I measure my HRV for athletic purposes and when my reading tells me I’m sympathetic dominant I’m apparently able to handle more stress in relation to a harder workout. If I am consistently in a sympathetic state, does this mean my body is, according to Woo’s theories, healthy in relation to its production of weight regulating hormones like dopamine and insulin? Just curious and wanting to pick the brains of all the science minded folks around here!
SNS activity, weight loss, and HRV (sorry for all the acronyms!)
I’ve been attempting to use HRV to monitor training/overtraining. I’ve found one complicating factor for myself is a very strong inverse relationship between HRV and temperature. At 55F my HRV is in the 80s (by Ellite HRV’s rating) and at 85F my HRV can be in the 50s and 20 minutes in a 120F bath will drop it to 1… Elite HRV does a podcast and in the episode with Alessandro Ferretti he discusses doing continuous glucose and HRV monitoring together and he found HRV is affected by blood glucose, I think HRV drops as glucose rises. So to make good use of HRV one needs to know all impacting factors and control or account for them.
Just adding a link to the podcast mentioned above:
https://elitehrv.com/hrv-ketones-glucose-food-sensitivities-alessandro-ferretti/
I also have anecdotal evidence that mct oil in the morning gives me an increase in HRV score - testing before/after my BPC. Hot flashes give me a huge reduction in score.
I’m no HRV expert, but my understanding that for training purposes, you need to consider the score you get first thing after waking and keep everything about that measurement consistent, including the position you’re in such as sitting, reclining, etc., so the variations you’re seeing wouldn’t be a factor unless your immediate environment is changing constantly.
Most people use the “Morning readiness reading” to evaluate training status. It calculates a baseline score from an average of your first few readings and compares against ones baseline to establish readiness. I like to sleep with my bedroom windows open and the room temperature varies widely both seasonly and sometimes day to day which creates a problem for me. Also I am actively experimenting witth a variety of fasting methods and other dietary manipulations. Learning that things like blood glucose level can impact HRV adds an additional wrinkle.
Not an expert on HRV and athletics, but HRV is both parasympathetic and sympathetic in general. You might want to check out the polyvagal theory, too, Erin - you might find it interesting and possibly helpful. The vagus nerve is definitely a huge influence on the neuroendocrine balance of the body.