Head Blood Flow Tracking

Continuing discussion started here by @dicarlo2:

This seems like an interesting tracker for those who have or believe to have blood flow issues to the brain, whether it is symptomatic difference from lying to standing, or even sitting in some positions, with cognitive changes during those positional changes, with exercise, temperature, food intake, and so on. Cause might be from an infectious disease (long COVID), CFS, POTS, autoimmunity, dysautonomia, medication, orthostatic hypotension but that is not continuous, NDD, etc.

Up to 20% of people above age 65 have some orthostatic hypotension, which is some dizziness when standing up (1), consequences can be falls, but I wonder about repeated changes of blood flow to the brain over days, weeks, months – years.

Prevalence of orthostatic hypotension increase with age:

Drop in BP while standing up is also associated with increased risk of dementia (2):

Previous research has pointed to an association between OH and dementia. To further explore the link, researchers used data on 11,644 adults who were on average 55 years old and participated in the Atherosclerosis Risk in Communities Study, which began in the late 1980s. Participants’ blood pressure was taken while lying down and then five more times in the first two minutes after they stood up. Their health was then monitored for the next decades. After a median of 26 years, one in five of the participants had developed dementia. The researchers observed that those whose systolic blood pressure dropped by at least 20 mmHg—enough for them to feel dizzy—in the first 30 seconds after standing had a 22% higher risk of developing dementia compared to those who did not experience OH.

It makes sense to me, with also the form of dementia that is vascular dementia, where atherosclerosis of the blood vessels around the brain limits blood flow.

Enter the Lumia Health tracker, which measures blood flow at the ear, thus measuring head blood flow.

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Specifically the Posterior auricular artery:

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Controls have only a 6% decrease in blood flow with their flow index while standing, while those with dysautonomia a 17% decrease, controls only are symptomatic at the stand transition, while those with dysautonomia have a sustained symptoms:

This is mostly of course only useful for those who know they experience a difference from positioning, temperature, or other similar things, as the reduce blood flow cause symptoms.

Here’s a comparison of blood flow with gold standard TCD Ultrasound, which shows that it follows it pretty closely with someone with dysautonomia:

With a correlation of 0.91 to the gold standard shown in this graph:

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Here’s an average dysfunctional blood flow for someone with dysautonamia showing great fluctuations:

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Compared to healthy:

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So it might be important to track and optimize for those especially with symptoms especially continuous, while for others the value might be diminished. But there can be people who don’t even know they have a reduced blood flow in certain situations, or it might be not enough to cause symptoms where the value is diminished. The value in treating symptoms aside, also long-term, possibly compounding effects on cognition and dementia that can be tracked from this factor, which seems real.

Cost is $379 + subscription, US only for now:

But it seems like there is an unmet need for this for especially people I listed earlier in the thread, but if it was dirt cheap I don’t see why anyone wouldn’t want to see their head blood flow over a longer period (say a week), just see what it is.

Does this make sense? Did I miss anything? How important is this, any other studies or interesting things for blood flow tracking? Feel free to discuss anything related here…

(1) Dizzy spells when you stand up: When should you worry? - Harvard Health

(2) https://hsph.harvard.edu/news/drops-in-blood-pressure-linked-to-higher-dementia-risk/

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