In the group with daily supplementation of 400 mg of magnesium, HRV parameters clearly increased
This is as I'd expect. I'd like to know if there's a dose relationship. I'll also need to see if this translates to clinical significant improvements in things like schizophrenia and CFS.
Although these findings may cause speculation that the observed vagal tone disruption merely results from anxiety produced by the presence of positive symptomology, additional studies have identified similar parasympathetic dysfunction among nonpsychotic relatives of individuals with schizophrenia.
This implies a causal role. The low parasympathetic tone precedes psychosis.
We found an association between short-term secondhand exposures to EC emissions, measured by nicotine concentrations, and decreased HRV as well as shortening of the QTc
It's hard to say what this tells me about my hypothesis that the 7 mg patch increases HRV. It really depends on their blood levels. The second-hand smoke machine is extremely unrealistic. They were exposed to 30 puffs of 1.8% nicotine e-juice in the first measurement interval. Assuming 150 puffs per ml, that's 3.6 mg smoked in a single 15 minute interval! I've not read the full study to confirm this calculation. Nonetheless, it's clear that these insane conditions require scrutiny. That's not even counting the fact that there's no placebo (Or even control). How am I supposed to know if this is not just an effect of being concern about inhaling e-smoke? I'm still searching for studies on low concentration of nicotine and HRV.
No significant differences were found for HRV in SCHypo. No association was found between HRV and SCHyper or SCHypo compared to euthyroid subjects in this sample of apparently healthy subjects.
This confirms that thyroid function probably lacks any (direct) effect sleep. Of course, not this evidence alone, but rather this combined with "Effects of Supraphysiological Doses of Levothyroxine on Sleep in Healthy Subjects: A Prospective Polysomnography Study"
Heart rate variability showed no differences between the 2 nights, but the low to high ratio (a parameter indicative of sympathetic nervous system activity) positively correlated with wake after sleep onset in night with nicotine patch.
This was with a 14 mg patch. A 21 mg patch would probably reduce HRV given that a 4 mg lozenge does so.
I still expect to find enhance HRV with 7 mg. This study supports that hypothesis to an extent. That it, it shows that 14 mg may be the tipping point between increased or decreased HRV from nicotine.
4 mg oral nicotine lozenge or placebo.
Assuming a half life of two hours, I calculated a 7 mg per day patch delivers a peak dosage of around 0.8 mg. Given that a 4mg lozenge has a bioavailability of 79%, this is equivalent to a 21 mg patch.
Given that we know anything above a 7 mg patch disrupts sleep (while 7 mg enhances sleep), it's unsurprising that HRV was reduced. I expect that a 1 mg lozenge or gum would increase HRV. Given that the above citation lists the bioavailability of a 2 mg lozenge at 50%, 2 mg may also increase HRV.
ConclusionThere is autonomic dysfunction in children with ADHD - reduction in overall HRV with sympathovagal imbalance with sympathetic dominance.
Unsurprising. This supports my hypothesis that ADHD is a sleep disorder. This hypothesis should hold sound regardless of EEG. That said, I also expect to find EEG disturbance during sleep in ADHD.
Sildenafil did not alter heart rate nor heart rate variability to a significant extent
I'm somewhat surprised. I was under the impression that cAMP signalled the wake phase, and cGMP signalled the sleep phase. I thus expected cGMP to increase parasympathetic tone (and therefore increase HRV)
Of the different instantaneous HRV indices computed by the point process technique, we selected the instantaneous high frequency power (HF) as our representative HRV metric. Heart rate HF power has garnered the greatest consensus for reflecting respiratory sinus arrhythmia (RSA) modulation by parasympathetic activity