Norepinephrine and the Mystery of Orthostatic Crises

What norepinephrine is, what functions in the body this “fight or flight” neurohormone serves, and approximately what its socionic profiles look like, we already know (see the post vk.com/wall-168821911_32356).

Let us recall what “orthostatic crises” are. This is a group of symptoms caused by insufficient blood supply to the brain when a person is in a standing position or, especially, rises abruptly from a lying position to a standing one. The first degree of a crisis – dizziness. The second, more severe – darkening of vision (“my vision darkens and everything seems to swim”). The third, final – sudden loss of consciousness with an uncontrolled fall of the body to the floor (fainting, also called orthostatic coma or orthostatic collapse).

What are the causes of all this? When a person is lying down, all of the person’s organs (the legs, the heart, and the head) are located at approximately the same level, that is, the blood in them has approximately the same hydrostatic pressure caused by the Earth’s gravity. But when a person approximately one meter seventy centimeters tall gets out of bed and stands up, the pressure in the cervical arteries supplying the brain with oxygen, owing to the hydrostatic difference, becomes 0.06 atmospheres lower than at the level of the heart and a full 0.16 atmospheres lower than at the heels. In order for oxygenated blood to reach the brain and for its movement through the cerebral vessels not to cease, the heart must urgently intensify its contractions, additionally increasing blood pressure in all vessels of the body. The giraffe has the greatest problems with this, but humans have them as well.

The body solves this problem by a two-level mechanism. The first level (the level of instantaneous action) – the so-called baroreceptors in the vessels, which are sensitive to changes in blood pressure. If the pressure in the cervical arteries begins to fall below a dangerous threshold, the baroreceptors issue an instantaneous command to the heart, and it likewise increases blood pressure in the system practically instantaneously. At the same time, a command is issued to launch the second-level support system – norepinephrine is injected into the bloodstream (compared with the lying position, its level in the blood rises severalfold within a minute). Norepinephrine, in turn, intensifies the work of the heart, but most importantly – it also constricts the vessels, thereby additionally increasing pressure in the circulatory system.

If there were no baroreceptors and everything depended on norepinephrine alone, then no one at all could avoid fainting when abruptly getting out of bed – the required norepinephrine level builds up over approximately a minute, whereas blood pressure in the head falls within a fraction of a second when a person stands up abruptly. If it were not for the baroreceptors, which instantaneously make the heart beat more intensely without waiting for the norepinephrine level to rise, then any person getting out of bed would faint from insufficient blood in the brain within three to four seconds.

Thus, those people who nevertheless experience fainting and dizziness when abruptly rising from a lying position (which is what is called orthostatic crises) – these are not at all the people who have problems with norepinephrine. No, these are people who, for some reason, have developed problems with the sensitivity of their vascular baroreceptors.

Moreover, orthostatic crises occur much more often precisely in people whose norepinephrine surges are powerful and whose baseline norepinephrine level is high. Why is this so? Here is the first, directly acting reason (possibly the most important one). Remember? Only during the first minute after rising from a lying position is the role of the baroreceptors in maintaining blood pressure decisive; thereafter, the role of maintaining it is taken over by the norepinephrine injected into the bloodstream. Therefore, as norepinephrine concentration rises, baroreceptor sensitivity decreases phasically. They do not stop functioning completely, but against a background of elevated norepinephrine they send much weaker commands to the heart.

The medical literature notes: “Paradoxically, however, arterial hypertension may be one of the causes of reduced baroreceptor sensitivity, increasing susceptibility to orthostatic hypotension.”

Therefore, if a person’s norepinephrine is already elevated while lying down (which is possible if the person is hypertensive or under nervous stress), then the sensitivity of the vascular baroreceptors in that lying person is weakened, and when standing up abruptly, that person is precisely the one who will “get” dizziness and fainting.

There appears to be a second reason for the relationship between high norepinephrine and reduced baroreceptor sensitivity, one that is more chronic in nature. Strong norepinephrine surges are perceived by the body as positively adaptive (Remember? Not merely an increase in blood pressure, but also preparation for fight or flight). In preparing the body for the “fight or flight” mode, an additional increase in blood pressure is desirable, and it should not be immediately eliminated and fully compensated for by the counteraction of the baroreceptors in the vessels. But the baroreceptors are aimed precisely at eliminating such fluctuations in blood pressure! Therefore, in those people who frequently have increased norepinephrine surges and whose baseline norepinephrine level is constantly elevated, baroreceptor sensitivity gradually weakens (their functioning is suppressed). Having become chronically less sensitive, they also respond more weakly to sudden changes in pressure when posture changes from lying to standing. Hence – more frequent orthostatic dizziness and fainting precisely among “specialists” in high norepinephrine (among hypertensive people – as well), not only when standing up abruptly but also simply during prolonged standing (especially – in a motionless position and when the chest is compressed and constricted – for example, by a tightly laced corset).

Prolonged standing in a motionless position (for example, during a church service) causes norepinephrine concentration to decline (norepinephrine requires movement; if there is no movement – it falls). But baroreceptor sensitivity in such people (“specialists” in usually high norepinephrine) is reduced; their baroreceptors do not compensate for the fall in blood pressure caused by the decrease in the level of norepinephrine in the blood. In addition, a tightly laced corset compresses the vessels, thereby reflexively switching off the norepinephrine mechanism for maintaining high blood pressure and, moreover, “pinching off” the access of blood to the cervical vessels. And stale air in a room where oxygen is already scarce aggravates the situation even further – and now the lady at the church service faints. With corsets removed from use, the number of fainting episodes at “standing” events decreased, but they by no means ceased altogether.

Thus, we expect that the socionic profiles of predisposition to orthostatic crises (fainting and dizziness) will resemble the socionic profiles of elevated norepinephrine and will correlate positively with them.

There is no disappointment; this is exactly what we obtain:

ORTHOSTATIC HYPOTENSION (ORTHOSTATIC CRISES, DIZZINESS AND FAINTING UPON RAPIDLY STANDING UP DUE TO A RAPID DROP IN BLOOD PRESSURE)

No. 187. Orthostatic hypotension (orthostatic crises, dizziness and fainting upon rapidly standing up due to a rapid drop in blood pressure)

(averaging the profiles of 3 scale questions, 1901 respondent answers in total; all profiles, except the 2nd and 3rd type profiles, are normalized to a unit sigma of the type profile). All profiles are given after corrective factor rotation.

Unnormalized type profile (deviations from the mean in units of the population standard deviation):

Approximate percentage of representatives of each type group showing raw responses “YES” and “RATHER YES” for the property (averaging all scale questions, taking the sign of the question into account, diagnosis by traits):

Contribution of the traits to the variance of the property, in percent:

1. When I stand up from a sitting position, I often begin to feel dizzy. 0.63
2. At least a couple of times a month, my vision darkens and I feel dizzy when I quickly get out of bed and stand up. 0.85
3. It has happened that, after abruptly standing up from a lying position, a second later I felt that everything before my eyes was swimming and my legs would not support me, and this lasted for several seconds. 0.89

(profiles - in the first table)

DIZZINESS WHILE STANDING.

No. 187. Dizziness

(averaging the profiles of 3 scale questions, 8352 respondent answers in total; all profiles, except the 2nd and 3rd type profiles, are normalized to a unit sigma of the type profile). All profiles are given after corrective factor rotation.

Unnormalized type profile (deviations from the mean in units of the population standard deviation):

Approximate percentage of representatives of each type group showing raw responses “YES” and “RATHER YES” for the property (averaging all scale questions, taking the sign of the question into account, diagnosis by traits):

Contribution of the traits to the variance of the property, in percent:

1. I often feel dizzy, to the point that I even lose my balance a little if I am standing. 0.92
2. When I am standing, I often begin to feel dizzy, to the point that my vision even “darkens” a little and I am pulled off to one side. 0.90
3. I often experience dizziness (5 - it occurs at least once a week, 4 - approximately once a month, 3 - on average once every six months, 2 - if it ever happened, it was only once or twice a very long time ago, 1- I do not know this of myself at all) 0.85

It should be noted that for dizziness while standing (unlike “pure” orthostatic crises caused by hypotension when rising from a lying position), a role may be played not only by chronically elevated norepinephrine, which weakens the baroreceptor system, but also by general malfunctions in the functioning of the brain’s vestibular apparatus (the cerebellum – first and foremost).

Questions coupled with dizziness (with profile correlations from 0.83 to 0.90):

1. Sometimes my thoughts sound as though “from the outside,” as if a radio has been switched on inside my head that, for some reason, cannot be switched off. 0.90
2. I often feel discomfort, although I cannot understand what exactly does not suit me, - everything as a whole is simply uncomfortable. 0.90
3. Most of all, I like to think about the past and the future, imagining the possible development of past or future events under various assumptions. 0.89
4. At times I am pursued by intrusive images of my imagination. 0.89
5. Sometimes my own body seems alien to me. 0.88
6. At times I find it difficult to focus my visual attention on my surroundings: everything seems somehow strange, as if it is trembling, swaying, and flickering. 0.87
7. Sometimes there is a strange feeling that everything around me is not really happening, but is make-believe, as in a theater. 0.87
8. If, while standing with my arms at my sides and my feet together, I close my eyes for several seconds, I immediately lose postural stability, begin to sway, and start falling somewhere (check this). 0.86
9. Sometimes I am pursued by some visual mental image that cannot be driven away by an effort of will. 0.86
10. Sometimes there is such a strange illusion as though I do not exist - the world around me that I perceive exists, but I do not exist in it. 0.86
11. It happens that for a few moments I sometimes lose contact with reality and cease to feel what is happening, although at that time I am not thinking about anything unrelated. 0.86
12. Several times a year or more often, I experience the illusion of “never having seen it before,” when well-known surrounding objects and people suddenly begin to seem strangely unfamiliar and new, as if I were seeing them for the first time. 0.86
13. Sometimes ordinary household objects that I look at seem somehow detached and incomprehensible. 0.85
14. I often have states in which my heart beats very slowly and somewhat irregularly, there is weakness in my body, I feel dizzy when getting up from the sofa, and I also frequently feel the urge to go to the toilet in order to empty my bowels or bladder. 0.85
15. I sometimes have unusual sensations of anticipation - I catch myself as if seeing in advance what will happen in a few seconds, as though the future and the present had momentarily changed places. 0.85
16. I am interested in topics related to mysterious phenomena; I like to be alone and reflect on the meaning of life, on the past, and on the future. 0.85
17. I often “play out versions” in my thoughts about my personal past - how the situation might have unfolded if only this or that had happened… 0.84
18. Sometimes I have had a strange feeling of not recognizing my own identity, as if I were another person, and in any case not the same person I was ten seconds or ten hours ago. 0.84
19. At times I have had a strange feeling as though I had lost the sense of separateness, stability, and indivisible wholeness of my human “self,” as though I were being spread across the surrounding world like butter on bread. 0.84
20. At times I experience disturbances of orientation to place - that is, I find it difficult to immediately recall and understand where I am at the moment (at home, or at work, or somewhere else, etc.). 0.84
21. All my life I have been trying to understand myself. 0.84
22. I often spend nighttime sleep time thinking about interesting ideas. 0.83
23. Sometimes a rapid trembling begins in my body (even when it is not cold) that cannot be stopped until it passes on its own. 0.83
24. I very much like, without any particular purpose and rather for self-soothing, to wander with my imagination through time and space. 0.83
25. At times some of my strange states and experiences cause me mild fright. 0.83

Intercorrelations:

The final table presented compares the profiles of high norepinephrine, high dopamine, predisposition to orthostatic crises (upon standing up), predisposition to gradually developing dizziness while standing, and one more property associated with high norepinephrine – clumsy handwriting.

As we can see, the highest correlation is found between the profile of high norepinephrine and the profile of predisposition to orthostatic crises (not counting the still higher correlation between norepinephrine and clumsy handwriting). By contrast, all these properties have correlations close to zero with dopamine.