Friday, 24 May 2013

Stress and Hypertension


 The unambiguously named American Institute of Stress gave me food for thought recently.  Certainly their opening paragraph in this interview with Bjorn Folkow echoed much of my own thoughts on the matter of HT:
  • What we refer to as “essential” or “primary” hypertension is generally viewed and often treated as if it were a distinct disease. However, it is merely the observation of consistent blood pressure measurements that exceed arbitrary values for which there is no obvious explanation. Like fever, hypertension is really a description rather than a diagnosis. As with an elevated temperature, it may have many varied causes that require very different treatments...As a consequence, therapy is often a hit or miss trial and error exercise or a buckshot approach consisting of a combination of drugs designed to lower an elevated blood pressure irrespective of its cause.

Folkow goes on to say,
  • Primary (essential) hypertension (PH) and the metabolic syndrome (MS) have much in common because their multifactorial backgrounds include several shared elements. In both conditions, a polygenetic predisposition interacts with environmental factors that overlap. Increased insulin resistance, which is considered to be the hallmark of MS, is common in PH, and conversely, an elevated blood pressure is frequently found in MS. A third important component in chronic hypertension is the gradual “upward structural setting” or remodeling of blood vessels and the heart that reinforces interactions between hereditary and environmental influences. This same phenomenon is also seen in metabolic syndrome.

    Genes alone are hardly sufficient to produce the clinical picture of either PH or MS since these disorders are almost absent in hunter-gatherer or small agricultural groups that have retained their traditional lifestyles for centuries. It is only when such rural enclaves are forced to follow the hectic and competitive lifestyles of modern society that rely on technologies rather than physical exercise that these leading “Diseases of Civilization” start to surface...From a biological perspective, a rise in blood pressure and blood sugar, enhanced alertness and other “fight or flight” responses to physical threats would have had survival value for our primitive ancestors. Unfortunately, they are now inappropriate for the mental and emotional stresses that modern man may encounter several times daily rather than once or twice a month. Repeatedly invoked, it is not hard to understand how they could contribute to hypertension, metabolic syndrome, peptic ulcers and other diseases depending on the interaction between genetic and environmental factors.
Folkow goes on to discuss a cortisol-abdominal fat connection,
  • The major culprit appears to be cortisol, since conditions that cause chronic cortisol elevations, like Cushing’s syndrome, exhibit abdominal obesity and all the characteristics of metabolic syndrome. Moreover, when a pituitary tumor or other cause of the problem is removed, these abnormalities disappear. Administration of prednisone and other synthetic glucocorticoids produces the same picture that is also reversed with cessation of therapy. Jim Henry showed that the defeat response was associated with increased abdominal fat in rats and studies in primates and humans subjected to stress who have elevated cortisols demonstrate similar results. As Per Björntorp has suggested, the sequence of events here seems to be that activation of the hypothalamic-pituitary-adrenal axis results in increased cortisol and other hormones that cause insulin resistance as well as visceral fat deposits that release free fatty acids which further decrease sensitivity to insulin in muscle and liver. These responses may have been useful for our primitive ancestors who required temporary increases in fuel for energy to respond to acute physical threats. However, the chronic elevation of sympathetic activity and stress hormones due to contemporary competitive and hectic lifestyles not only provides few benefits but can prove deadly.
From a personal perspective I've found a lot of trouble identifying how blood pressure should fluctuate throughout the day.  I did find one diagram, but I needed more detail, I mean, one expects that if you go from standing still to sprinting, or from standing to sitting, quite dramatic spikes could occur in BP as your body seeks to find a new equilibrium.  The point being that there must be some time-lag for this equilibrium to be reached, and the parameters required to reach that equilibrium would be dynamically changing throughout the course of the day, at times second to second.  This is before we consider psychological factors.  Folkow discusses this,
  • Sir George Pickering’s group showed several decades ago the tremendous blood pressure variations that can occur in normotensive individuals during daily activities ranging from sleep to physical activity and strong emotional excitement. Nevertheless, it is not the magnitude of such sporadic short bursts of blood pressure elevation that causes problems. The structural upwards resetting of the cardiovascular system responsible for chronic hypertension depends more on the extent and duration of the average pressure load for long periods of time. These result from relatively mild but frequent daily psychosocial challenges that elicit defense responses with widespread neurohormonal excitatory influences. Mental stress tests like Brod’s forced mental arithmetic can stimulate the “emotional brain” to produce mild defense (or defeat) reactions but this is different than the daily life situations of chronic worries, frustration, challenges that people face in their daily lives.
 And with regard to salt (the cutting of which seems to have a negative impact on ventricular health),
  • The importance of salt intake is also a subject of considerable controversy. As you have pointed out in previous Newsletters, official recommendations for all Americans to sharply restrict salt seem unwarranted. This is supported by Graudal’s very thorough meta-analysis of almost 60 well-controlled low-salt studies in normotensives, which found an average fall in mean arterial pressure of only a meager 0.6 mm Hg.(24) However, renin and catecholamine release was increased three or four fold and heart rate also rose in the majority of patients. As explained elsewhere, this could lead to an increased load on the left ventricle in addition to other undesirable consequences.
 The interview turns up a nice experiment involving Italian nuns, and supports the beneficial effect of meditation and relaxation as a means to reducing stress and...
  • ...its important role is illustrated by a 30-year follow-up study of Italian nuns in a closed order who pursued a peaceful lifestyle characterized by silence, meditation, regular work activities and isolation from society.(28) Their blood pressures at age 65-70 were only a few mm Hg. different than when initially recorded 3 decades earlier in contrast to a carefully matched group of women exposed to urban Italian lifestyles who showed the usual progressive rise with age seen in most Western countries. The incidence of cardiovascular disease and death was also twice as high in this control group compared to the nuns although there was no difference in family history of hypertension or salt intake. Cholesterol levels and body weight were actually higher in the nuns and the authors concluded that it was primarily their stress-free cooperative rather than competitive environment that provided these cardioprotective effects.
Folkow concludes by throwing in a superb concept; our 'emotinal brain',
  • Laziness and lack of exercise could certainly be a factor, along with other deleterious lifestyle changes our bodies have not had time to adapt to. Although blessed with a remarkable neocortex, Homo sapiens has the same “emotional brain’” designed for preservation of self and species in a primitive world that exists in all other mammals. It was the remarkable efficiency of these limbic-hypothalamic mechanisms that made it possible for our ancestors to survive physical threats for millions of years of evolution. While appropriate for a hunter gatherer’s existence and small group enclaves, contemporary man faces a barrage of hectic and competitive challenges and daily stresses that are bound to arouse such protective mechanisms that are no longer appropriate but have boomeranged to produce deadly diseases. 
 Does this concept sound familiar?

2 comments:

FeelGoodEating said...

A,

years ago my sister had a run in with a "potential/tumor"

She was scheduled for a serious operation and removal of chunk of inner body.

a family friend and retired physician intervened.

He said "cancer is too damn tricky. When not in the latter stages of the disease, treatment protocols are far too aggresive and invasive early on, especially considering that we don't even understand the disease at that stage. He went on to say, LIKE BLOOD pressure, biopsys and testing are simple "moment in time snap shots". They are not even close to a complete picture.

My sister did not have th adivsed surgery, she went on to have a 3rd child and now 16 years later, never had any problems.

Eventhough this was a while back...
I don't think much has changed.
These "snapshots of time" are still the go to for diagnosis. I'm no phd or even a very intelectual guy, but from a gut level...it just makes a whole lot of sense to me.

Marc

Asclepius said...

Hi Marc. It takes courage to go off-piste with health issues, but as we know, formal health advice is fallible and doctors treat populations not individuals (and that is before we get to bad science and big-pharm corruption). It's got to the point where anyone with reasonable intelligence and an internet connection can tailor their own path back to health. It comes with risks but I'd rather keep control of my own destiny as much as possible.

It is good to hear things worked out for your sister.