sábado, 7 de marzo de 2009

MIND BODY HEALTH http://www.mind-body-health.net/index.html?intro.html&1
Mind-Body-Health.net

Information and research into chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME), burnout, the HPA axis, the placebo effect and the relationship between mental attitude, lifestyle and physical health.
NEW!



Based on the latest research into areas such as the placebo effect and the circadian body clock, this website presents information showing how the mind interacts with the immune system and the body's hormone rhythms via the HPA axis to influence health, vitality and stress tolerance. This site also presents the first-ever cohesive theory to explain burnout, chronic fatigue syndrome (CFS, also known as Myalgic Encephalomyelitis or ME), irritable bowel syndrome (IBS), post-viral fatigue syndrome (PVFS) and other misunderstood illnesses, explaining why these illnesses occur and how they can be treated.

Many illnesses such as CFS, IBS and burnout are caused by an abnormally suppressed HPA axis, the body's stress tolerance and energy regulation system. As the HPA axis also regulates the immune system, an imbalance can result in a susceptibility to many types of illness.

This site also provides information on the placebo effect, which, although mostly ignored or ridiculed, is actually a very powerful healing force and appears to operate through the HPA axis.

For further information, click on the links at the left, and see also the Mind-Body Health and Stress Tolerance book (now available on this site as a free e-book) which provides a more detailed explanation of the factors involved, as well as more background material.

Also see the News and Latest Research section for the latest research findings into CFS, burnout and related conditions.

This website was developed by David Jameson, a recovered CFS patient who has been symptom free for over 7 years.





Burnout


The burnout syndrome is a set of physical and mental symptoms including exhaustion, fatigue, headaches, depression, anxiety, sleep problems, non-specific pain and digestive problems, although many other symptoms can also occur.

The symptoms of burnout and CFS are identical except in their severity, with the dividing line between the two diagnoses being set at the point where the symptoms become highly disabling.

A study on teachers suffering from burnout found that those teachers who scored highest on the "Maslach Burnout Inventory" had the lowest levels of cortisol throughout the day. The teachers who said they were under stress but not suffering from burnout had the highest levels of cortisol.

The study also found that those teachers who were highest on the burnout scales had the highest levels of physical illness complaints. The stress level did not alter the number of physical complaints among the teachers who were low on the scale. The factors associated with high levels of burnout were low job satisfaction, low perceived levels of support, low perceived levels of being able to cope with stress and high levels of emotional exhaustion (although this last one could be a symptom rather than a cause).

This study highlights a number of important findings. First of all, that mental attitude has a large influence over the ability to handle stress without suffering from burnout. Second, that people suffering from burnout have higher levels of physical illness complaints. And third, that low levels of cortisol (and a suppressed HPA axis) seem to be associated with low stress tolerance and high levels of burnout.


This particular study also found that stress and burnout are separate variables - people can suffer from burnout in the absence of stress, and vice-versa.

Causes of Burnout
Popular belief is that burnout is the result of excessive stress. This is the view that Hans Selye took when he presented his General Adaptation Syndrome theory of stress, which has the following three stages:

[1] The alarm phase at the onset of the stress, which causes the adrenal cortex to discharge all of its supply of stored hormones into the blood.

[2] The stage of resistance, where the adrenal cortex enlarges due to continued stimulation by ACTH, which results in an enhanced ability to manufacture and secrete higher levels of cortisol. During this stage there is a greater ability to deal with stress.

[3] The stage of exhaustion, which eventually comes after continued stress, and results in symptoms similar to the alarm phase. During this phase the adrenal glands shrink and levels of cortisol fall, resulting in an inability to cope with stress.

From his results, Selye proposed that many illnesses in humans which are not obviously caused by an external pathogen, such as liver disease and heart disease, may be due to the psychological stresses of modern life. He proposed that the continual stresses of modern life result in the exhaustion phase of the GAS, which then leads to one of any number of physical illnesses. This notion has been mostly rejected today due to the advances in understanding about how the body works, with a greater concentration on the underlying mechanism of disease. In fact, most of Selye's work seems to have been forgotten today, and his GAS has largely been rejected. While it is true that he tried to apply his theories too broadly, there is one very important fact which he discovered and which is largely ignored today, and that is the exhaustion phase of the GAS, which appears to be the same state as burnout.
Recent research shows that burnout (in terms of reduced HPA axis response and low cortisol) can be caused by four factors:

[1] Excessive long-term stress
[2] Stress followed by rest
[3] Long-term illness
[4] Negative mental attitude

Relationship to CFS
Burnout and CFS may initially appear to be very different, but closer investigation shows that they are in fact quite similar. The same hormonal abnormalities appear in both groups, namely reduced cortisol and a suppressed HPA axis, as well as a tendency to suffer from various physical illness complaints.

Also, a significant proportion of CFS patients say that their illness began during a period of high stress. In some cases this was emotional stress, but in other cases it was simply a high-pressure job (which in many cases the person did not find "stressful" in the negative sense).

In fact, all of the known triggers for CFS, such as emotional stress, negative mental attitude, viral infection, and working in a high-pressure job, are the same factors which cause burnout. CFS can therefore be thought of as a state of long-term burnout in the absence of stress.

References
Pruessner JC, Hellhammer DH, Kirschbaum C, "Burnout, perceived stress, and cortisol responses to awakening", Psychosomatic Medicine 1999;61:197-204

Morgan CA 3rd, Cho T, Hazlett G, Coric V, Morgan J, "The impact of burnout on human physiology and on operational performance: a prospective study of soldiers enrolled in the combat diver qualification course", Yale J Biol Med. 2002 Jul-Aug;75(4):199-205








Cortisol




La hidrocortisona o cortisol es el principal glucocorticoide segregado por la corteza suprarrenal humana y el esteroide más abundante en la sangre periférica, si bien también se forman cantidades menores de corticosterona.

En el hombre, estudios cinéticos de la conversión del colesterol libre del plasma en cortisol han demostrado que, en esencia, todo el cortisol secretado deriva del colesterol circulante en condiciones basales y como resultado de la estimulación aguda con adrenocorticotropina (ACTH).

Contenido-

1 Producción
2 Función
3 Neurogénesis
4 Otras funciones
5 Véase también
6 Referencias
7 Bibliografía
8 Véase también.



Producción

La secreción de cortisol está gobernada por el ritmo circadiano de la hormona adrenocorticotropa (ACTH), aumentando en las horas de la mañana y después de cada comida.
circadiano, na.

(Del lat. circa, cerca, y dies, día).


1. adj. Perteneciente o relativo a un período de aproximadamente 24 horas. Se aplica especialmente a ciertos fenómenos biológicos que ocurren rítmicamente alrededor de la misma hora, como la sucesión de vigilia y sueño.



Real Academia Española © Todos los derechos reservados



El cortisol se une a proteínas en el plasma sanguíneo, principalmente a la globulina fijadora de cortisol (CBG) y un 5% a la albúmina; el resto, entre 10 y 15% se encuentra circulando libre. Cuando la concentración del cortisol alcanza niveles de 20-30 g/dL en la sangre, la CBG se encuentra saturada y los niveles de cortisol plasmáticos aumentan velozmente.[1]

La vida media del cortisol es de 60 - 90 minutos, aunque tiende a aumentar con la administración de hidrocortisona, en el hipertiroidismo, la insuficiencia hepática o en situaciones de estrés.


Función -

Es un esteroide con doble función metabólica:

acción glucocorticoide: metabolismo de hidratos de carbono, proteínas y grasas
acción mineralocorticoide: homeostasis del agua y los electrólitos
Aumenta la producción de glucógeno en el hígado e inhibe la utilización periférica de glucosa.

Su empleo en clínica se debe fundamentalmente a su efecto antiinflamatorio.

El cortisol, a diferencia de los otros esteroides suprarrenales, ejerce un control por realimentación negativa sobre la síntesis de ACTH al suprimir la transcripción del gen de la ACTH en la hipófisis y suprime la formación de la hormona liberadora de hormona adrenocorticotropa.


Neurogénesis -

Esta hormona y sus alteraciones se han relacionado con la neurogénesis, especialmente en adultos, lo cual a su vez se ha visto como uno de los factores incidentes en la depresión humana.[2]


Otras funciones -

Esta hormona además de promover la síntesis de glucosa a través de vías (como la formación de glucosa a partir de la glucogeno encontrado en musculos o en hígado) disminuye la cantidad de proteína de los tejidos periféricos, inhibiendose la síntesis de proteínas y ácidos nucléicos y aumenta su degradación para proporcionar aminoácidos sobre todo alanina, para la utilización en el hígado, ya que todos los aminoácidos libres, cuando actúa el cortisol van a los hepatocitos para:

Formación de proteínas en los hepatocitos.
Formación de proteínas plasmáticas.
Síntesis de enzimas necesarias para la glucogenólisis, gluconeogénesis y glucogénesis.
Disminución de la tasa de utilización de glucosa en el cuerpo (efecto antiinsulinico-elevación de la glucosa sanguinea)
Utilización de los ácidos grasos como fuente de energía.
Mediadores de las respuestas alérgicas, efectos conocidos como eritemas.
Es un hormona que se libera en grandes cantidades en momentos de estres, potenciando la vias metabólicas catabolicas, por lo tanto elevando la concentración de glucosa, aminoacidos, y lipidos (este último importante en la secreción cronica de cortisol, dando como consecuencia problemas de dislipidemias, que más tarde desemboca en problemas cardiovasculares)


Inhibe la función de las células óseas y el depósito de la matriz de colágeno e inhibe la absorción intestinal de calcio de modo que se altera la calcificación de la matriz ósea. El cortisol puede interferir con la síntesis gástrica de prostaglandinas que son necesarias para mantener la barrera protectora normal contra el jugo gástrico y la pepsina. La fragilidad capilar aumenta y son frecuentes los hematomas con traumatismos pequeños. Se produce un aumento en la concentración de hemoglobina y el número de eritrocitos en la sangre.

Véase también Prueba de estimulación con ACTH

Referencias Katzung, Bertram G. ;(2007). «Chapter 39. Adrenocorticosteroids & Adrenocortical Antagonists», Basic & Clinical Pharmacology, 9 edición, McGraw-Hill. ISBN 0071451536.
↑ *Gerd Kempermann: Neurogénesis en Mente y cerebro, nº19, julio 2006

Bibliografía -Manual de Fisiologia Medica Guyton Hall.Decima Edición. editorial Mc Graw Hill-Interamericana