Allostasis and allostatic load: Difference between revisions

Revision as of 20:20, 12 November 2008

Elaborated definitions and examples

Jeongok Logan and Debra Barksdale at the University of North Carolina Chapel Hill articulate a succinct definition of allostasis and allostatic load:

Allostasis is the extension of the concept of homeostasis and represents the adaptation process of the complex physiological system to physical, psychosocial and environmental challenges or stress. Allostatic load is the long-term result of failed adaptation or [failed] allostasis, resulting in pathology and chronic illness.^[4]

Bruce McEwen and Teresa Seeman, in collaboration with the Allostatic Load Working Group, elaborate and give specific examples:

For each system of the body, there are both short-term adaptive actions (allostasis) that are protective and long-term effects that can be damaging (allostatic load). For the cardiovascular system, a prominent example of allostasis is the role of catecholamines in promoting adaptation by adjusting heart rate and blood pressure to sleeping, waking, physical exertion (citation). Yet, repeated surges of blood pressure in the face of job stress or the failure to shut off blood pressure surges efficiently accelerates atherosclerosis and synergizes with metabolic hormones to produce Type II diabetes, and this constitutes a type of allostatic load (see (citation)). Closely related to this is the role of adrenal steroids in metabolism. Whereas adrenal steroids promote allostasis by enhancing food intake and facilitating the replenishment of energy reserves, the overactivity of this system involving repeated HPA activity in stress or elevated evening cortisol leads to allostatic load in terms of insulin resistance, accelerating progression towards Type II diabetes, including abdominal obesity, atherosclerosis, and hypertension (citations). In the brain, actions of adrenal steroids and catecholamines that are related to allostasis include promoting retention of memories of emotionally-charged events, both positive and negative. Yet, overactivity of the HPA axis together with overactivity of the excitatory amino acid neurotransmitters promotes a form of allostatic load, consisting of cognitive dysfunction by a variety of mechanisms that involve reduced neuronal excitability, neuronal atrophy and, in extreme cases, death of brain cells, particularly in the hippocampus (citations).^[5]

McEwen and Seeman divide allostatic load into several distinct types of scenarios:^[5]

Stress overload, such as that caused by severe and repeated economic burdens, which potentially leads to physical and mental dysfunctions;
Stress adaptation failure, where mediators of a stress response fail to diminish in response to repeated similar stress events, such as repeated taking of exams during course work;
Stress response persistence following cessation of the stressor;
Stressors that chronically disturb normal circadian rhythms, such as sleep deprivation;
Stress response inadequacy that leads to overreaction of other systems.

In their book on the endocrine factors in aging, Derek Chadwick and Jamie Goode characterize allostasis as follows, and contrast it with homeostasis:

Speaking generally, allostasis is distinct from homeostasis in maintaining a compensated equilibrium rather than a physiological equilibrium: stability is maintained at a price. The allostatic set point is abnormal relative to the homeostatic set point, the system is inherently less stable, and it has a relatively narrow dynamic range. Finally, a system in allostasis leads to pathology whereas a system in homeostasis does not. ^[6]

Chadwick and Goode go on to compare the pathology and regulatory dysfunctions caused by chronic stress (allostatic load) and by the aging process. The consider the findings supportive of the notion that allostatic load plays a role in determining longevity. They point to evidence that similar disturbances in aging and chronic stress occur in the daily rhythm of the brain's interactions between its hypothalamus and pituitary gland, and in body temperature regulation, drawing attention to allostatic load as a factor in aging.^[6]

Role of brain in the physiology and neurobiology of stress

Holding refs: ^[7] ^[8]

To learn more about allostasis and allostatic load

See annotations of books and articles under Bibliography tab at top of page, or click here.

Also see links under External Links tab at top of page, or click here.

References

Citations and notes

Many citations to the journal articles listed below include abstracts of the articles. The abstracts often amplify the information contained in the Citizendium article. Some book citations will have attached excerpts that further amplify the information contained in the Citizendium article.

Most citations to articles listed here include links to full-text. Accessing full-text may require personal or institutional subscription. Nevertheless, usually the links will show the abstracts of the articles, free without subscription. Links to books variously may open to full-text, or to the publishers' description of the book with or without downloadable selected chapters, reviews, and table of contents. Books with links to Google Books often offer extensive previews of the books' text.

↑
McEwen BS. (1998) Stress, adaptation, and disease. Allostasis and allostatic load. Ann.N.Y.Acad.Sci. 840:33-44. PMID 9629234.
Abstract:
- Adaptation [of the organism] in the face of potentially stressful challenges involves activation of neural, neuroendocrine and neuroendocrine-immune mechanisms.
- This has been called "allostasis" or "stability through change" by Sterling and Eyer (Fisher S., Reason J. (eds): Handbook of Life Stress, Cognition and Health. J. Wiley Ltd. 1988, p. 631), and allostasis is an essential component of maintaining homeostasis.
- When these adaptive systems are turned on and turned off again efficiently and not too frequently, the body is able to cope effectively with challenges that it might not otherwise survive.
- However, there are a number of circumstances in which allostatic systems may either be overstimulated or not perform normally, and this condition has been termed "allostatic load" or the price of adaptation (McEwen and Stellar, Arch. Int. Med. 1993; 153: 2093.).
- Allostatic load can lead to disease over long periods. Types of allostatic load include:
- (1) frequent activation of allostatic systems;
- (2) failure to shut off allostatic activity after stress;
- (3) inadequate response of allostatic systems leading to elevated activity of other, normally counter-regulated allostatic systems after stress.
- Examples will be given for each type of allostatic load from research pertaining to autonomic, CNS, neuroendocrine, and immune system activity.
- The relationship of allostatic load to genetic and developmental predispositions to disease is also considered.
↑ Sterling P. Eyer J. (1998) Allostasis: A New Paradigm to Explain Arousal Pathology. In: Handbook of life stress, cognition, and health. Eds., Shirley Fisher and James Reason. Chichester: Wiley. ISBN 0471912697
↑
McEwen,B.S.; Stellar,E. (1993) Stress and the individual. Mechanisms leading to disease. Arch.Int.Med 153:2093-2101. PMID 8379800.
Abstract:
- OBJECTIVE: This article presents a new formulation of the relationship between stress and the processes leading to disease. It emphasizes the hidden cost of chronic stress to the body over long time periods, which act as a predisposing factor for the effects of acute, stressful life events. It also presents a model showing how individual differences in the susceptibility to stress are tied to individual behavioral responses to environmental challenges that are coupled to physiologic and pathophysiologic responses.
- DATA SOURCES: Published original articles from human and animal studies and selected reviews. Literature was surveyed using MEDLINE.
- DATA EXTRACTION: Independent extraction and cross-referencing by us.
- DATA SYNTHESIS: Stress is frequently seen as a significant contributor to disease, and clinical evidence is mounting for specific effects of stress on immune and cardiovascular systems. Yet, until recently, aspects of stress that precipitate disease have been obscure. The concept of homeostasis has failed to help us understand the hidden toll of chronic stress on the body. Rather than maintaining constancy, the physiologic systems within the body fluctuate to meet demands from external forces, a state termed allostasis. In this article, we extend the concept of allostasis over the dimension of time and we define allostatic load as the cost of chronic exposure to fluctuating or heightened neural or neuroendocrine response resulting from repeated or chronic environmental challenge that an individual reacts to as being particularly stressful. [Emphasis added]
- CONCLUSIONS: This new formulation emphasizes the cascading relationships, beginning early in life, between environmental factors and genetic predispositions that lead to large individual differences in susceptibility to stress and, in some cases, to disease. There are now empirical studies based on this formulation, as well as new insights into mechanisms involving specific changes in neural, neuroendocrine, and immune systems. The practical implications of this formulation for clinical practice and further research are discussed.
↑
Logan JG, Barksdale DJ. (2008) Allostasis and allostatic load: expanding the discourse on stress and cardiovascular disease. J.Clin.Nurs. 17:201-208. PMID 18578796.
Abstract:
- AIM: The aim of this discursive paper is to introduce allostasis and allostatic load, which are relatively new concepts proposed to explain physiological responses to stress, and to suggest ways in which allostasis theory can be applied to the development of clinical interventions to increase resilience for producing better health outcome.
- BACKGROUND: Common explanations of stress have failed adequately to explicate its association with health and chronic illness. Allostasis is the extension of the concept of homeostasis and represents the adaptation process of the complex physiological system to physical, psychosocial and environmental challenges or stress. Allostatic load is the long-term result of failed adaptation or allostasis, resulting in pathology and chronic illness.
- DISCUSSION: The concepts of allostasis and allostatic load introduced the idea that external challenges initiate allostasis and chronic stress causes allostatic load that can be measured with multiple biomarkers. Finding from several studies suggests that higher allostatic load is associated with worse health outcomes. Resilience represents successful allostasis and strategies can be implemented to enhance resilience and thereby improve health outcomes.
- CONCLUSIONS: This theoretical model provides a comprehensive explanation of the human body's adaptation processes in response to stress and the results of failed adaptation over time. In addition, combining the concepts of allostasis and resilience may help us to understand and implement clinical strategies better to reduce or prevent the debilitating physiological and psychological effects of chronic stress and chronic illness.
- RELEVANCE TO CLINICAL PRACTICE: Clinical practice should be based on a solid theoretical foundation to improve health outcomes. Strategies to manage stress and increase resilience along with clinical interventions to manage the physiological responses to chronic stress are necessary to assist in preventing and controlling the detrimental effects of chronic disease on human life.
↑ ^5.0 ^5.1 Bruce McEwen and Teresa Seeman in collaboration with the Allostatic Load Working Group. (1999) Allostatic Load and Allostasis.
↑ ^6.0 ^6.1
Chadwick D., Goode J. (2002) Endocrine Facets of Ageing. John Wiley and Sons. ISBN 0471486361, ISBN 9780471486367.
- ”Social and medical developments have recently led to a dramatic increase in life expectancy. This has inspired the study of organismic changes associated with healthy ageing, in particular the erosion of homeostatic capabilities in multiple endocrine systems. This book reviews advances in the understanding of endocrine facets of ageing. It considers the relative magnitudes and time courses of different endocrine adaptations in the ageing human and experimental animal, addressing the influence of external factors on the rates of progression of endocrine sequelae in ageing, the mechanisms that underlie the disarray of endocrine axes in ageing, and the implications of therapeutic reconstitution of hormones in ageing. This book: Considers the mechanisms of ageing and hormonal changes that occur with age. Discusses healthy ageing and the relationships between hormonal changes and pathophysiological conditions such as atherosclerosis and age-related bone loss. Draws together contributions from basic and clinical research, to identify and stimulate promising new research directions.”
↑
McEwen BS. (2000) [10.1016/S0893-133X(99)00129-3 Allostasis and allostatic load: implications for neuropsychopharmacology.] Neuropsychopharmacology 22:108-124.
- Abstract (bulleted for ease of reading): The primary hormonal mediators of the stress response, glucocorticoids and catecholamines, have both protective and damaging effects on the body. In the short run, they are essential for adaptation, maintenance of homeostasis, and survival (allostasis). Yet, over longer time intervals, they exact a cost (allostatic load) that can accelerate disease processes.
- The concepts of allostasis and allostatic load center around the brain as interpreter and responder to environmental challenges and as a target of those challenges.
- In anxiety disorders, depressive illness, hostile and aggressive states, substance abuse, and post-traumatic stress disorder (PTSD), allostatic load takes the form of chemical imbalances as well as perturbations in the diurnal rhythm, and, in some cases, atrophy of brain structures.
- In addition, growing evidence indicates that depressive illness and hostility are both associated with cardiovascular disease (CVD) and other systemic disorders. A major risk factor for these conditions is early childhood experiences of abuse and neglect that increase allostatic load later in life and lead individuals into social isolation, hostility, depression, and conditions like extreme obesity and CVD. Animal models support the notion of lifelong influences of early experience on stress hormone reactivity.
- Whereas, depression and childhood abuse and neglect tend to be more prevalent in individuals at the lower end of the socioeconomic ladder, cardiovascular and other diseases follow a gradient across the full range of socioeconomic status (SES).
- An SES gradient is also evident for measures of allostatic load. Wide-ranging SES gradients have also been described for substance abuse and affective and anxiety disorders as a function of education. These aspects are discussed as important, emerging public health issues where the brain plays a key role.
↑
McEwen BS. (2007) Physiology and neurobiology of stress and adaptation: central role of the brain. Physiol Rev 87:873-904.
- Abstract (bulleted for ease of reading):
- The brain is the key organ of the response to stress because it determines what is threatening and, therefore, potentially stressful, as well as the physiological and behavioral responses which can be either adaptive or damaging.
- Stress involves two-way communication between the brain and the cardiovascular, immune, and other systems via neural and endocrine mechanisms.
- Beyond the "flight-or-fight" response to acute stress, there are events in daily life that produce a type of chronic stress and lead over time to wear and tear on the body ("allostatic load").
- Yet, hormones associated with stress protect the body in the short-run and promote adaptation ("allostasis").
- The brain is a target of stress, and the hippocampus was the first brain region, besides the hypothalamus, to be recognized as a target of glucocorticoids.
- Stress and stress hormones produce both adaptive and maladaptive effects on this brain region throughout the life course.
- Early life events influence life-long patterns of emotionality and stress responsiveness and alter the rate of brain and body aging.
- The hippocampus, amygdala, and prefrontal cortex undergo stress-induced structural remodeling, which alters behavioral and physiological responses.
- As an adjunct to pharmaceutical therapy, social and behavioral interventions such as regular physical activity and social support reduce the chronic stress burden and benefit brain and body health and resilience

[mcewen1998-1] McEwen BS. (1998) Stress, adaptation, and disease. Allostasis and allostatic load. Ann.N.Y.Acad.Sci. 840:33-44. PMID 9629234.
Abstract:
Adaptation [of the organism] in the face of potentially stressful challenges involves activation of neural, neuroendocrine and neuroendocrine-immune mechanisms.

This has been called "allostasis" or "stability through change" by Sterling and Eyer (Fisher S., Reason J. (eds): Handbook of Life Stress, Cognition and Health. J. Wiley Ltd. 1988, p. 631), and allostasis is an essential component of maintaining homeostasis.

When these adaptive systems are turned on and turned off again efficiently and not too frequently, the body is able to cope effectively with challenges that it might not otherwise survive.

However, there are a number of circumstances in which allostatic systems may either be overstimulated or not perform normally, and this condition has been termed "allostatic load" or the price of adaptation (McEwen and Stellar, Arch. Int. Med. 1993; 153: 2093.).

Allostatic load can lead to disease over long periods. Types of allostatic load include:

(1) frequent activation of allostatic systems;

(2) failure to shut off allostatic activity after stress;

(3) inadequate response of allostatic systems leading to elevated activity of other, normally counter-regulated allostatic systems after stress.

Examples will be given for each type of allostatic load from research pertaining to autonomic, CNS, neuroendocrine, and immune system activity.

The relationship of allostatic load to genetic and developmental predispositions to disease is also considered.

[2] Adaptation [of the organism] in the face of potentially stressful challenges involves activation of neural, neuroendocrine and neuroendocrine-immune mechanisms.

[3] This has been called "allostasis" or "stability through change" by Sterling and Eyer (Fisher S., Reason J. (eds): Handbook of Life Stress, Cognition and Health. J. Wiley Ltd. 1988, p. 631), and allostasis is an essential component of maintaining homeostasis.

[4] When these adaptive systems are turned on and turned off again efficiently and not too frequently, the body is able to cope effectively with challenges that it might not otherwise survive.

[5] However, there are a number of circumstances in which allostatic systems may either be overstimulated or not perform normally, and this condition has been termed "allostatic load" or the price of adaptation (McEwen and Stellar, Arch. Int. Med. 1993; 153: 2093.).

[6] Allostatic load can lead to disease over long periods. Types of allostatic load include:

[7] (1) frequent activation of allostatic systems;

[8] (2) failure to shut off allostatic activity after stress;

[9] (3) inadequate response of allostatic systems leading to elevated activity of other, normally counter-regulated allostatic systems after stress.

[10] Examples will be given for each type of allostatic load from research pertaining to autonomic, CNS, neuroendocrine, and immune system activity.

[11] The relationship of allostatic load to genetic and developmental predispositions to disease is also considered.

[sterling1988-2] Sterling P. Eyer J. (1998) Allostasis: A New Paradigm to Explain Arousal Pathology. In: Handbook of life stress, cognition, and health. Eds., Shirley Fisher and James Reason. Chichester: Wiley. ISBN 0471912697

[mcewen1993-3] McEwen,B.S.; Stellar,E. (1993) Stress and the individual. Mechanisms leading to disease. Arch.Int.Med 153:2093-2101. PMID 8379800.
Abstract:
OBJECTIVE: This article presents a new formulation of the relationship between stress and the processes leading to disease. It emphasizes the hidden cost of chronic stress to the body over long time periods, which act as a predisposing factor for the effects of acute, stressful life events. It also presents a model showing how individual differences in the susceptibility to stress are tied to individual behavioral responses to environmental challenges that are coupled to physiologic and pathophysiologic responses.

DATA SOURCES: Published original articles from human and animal studies and selected reviews. Literature was surveyed using MEDLINE.

DATA EXTRACTION: Independent extraction and cross-referencing by us.

DATA SYNTHESIS: Stress is frequently seen as a significant contributor to disease, and clinical evidence is mounting for specific effects of stress on immune and cardiovascular systems. Yet, until recently, aspects of stress that precipitate disease have been obscure. The concept of homeostasis has failed to help us understand the hidden toll of chronic stress on the body. Rather than maintaining constancy, the physiologic systems within the body fluctuate to meet demands from external forces, a state termed allostasis. In this article, we extend the concept of allostasis over the dimension of time and we define allostatic load as the cost of chronic exposure to fluctuating or heightened neural or neuroendocrine response resulting from repeated or chronic environmental challenge that an individual reacts to as being particularly stressful. [Emphasis added]

CONCLUSIONS: This new formulation emphasizes the cascading relationships, beginning early in life, between environmental factors and genetic predispositions that lead to large individual differences in susceptibility to stress and, in some cases, to disease. There are now empirical studies based on this formulation, as well as new insights into mechanisms involving specific changes in neural, neuroendocrine, and immune systems. The practical implications of this formulation for clinical practice and further research are discussed.

[14] OBJECTIVE: This article presents a new formulation of the relationship between stress and the processes leading to disease. It emphasizes the hidden cost of chronic stress to the body over long time periods, which act as a predisposing factor for the effects of acute, stressful life events. It also presents a model showing how individual differences in the susceptibility to stress are tied to individual behavioral responses to environmental challenges that are coupled to physiologic and pathophysiologic responses.

[15] DATA SOURCES: Published original articles from human and animal studies and selected reviews. Literature was surveyed using MEDLINE.

[16] DATA EXTRACTION: Independent extraction and cross-referencing by us.

[17] DATA SYNTHESIS: Stress is frequently seen as a significant contributor to disease, and clinical evidence is mounting for specific effects of stress on immune and cardiovascular systems. Yet, until recently, aspects of stress that precipitate disease have been obscure. The concept of homeostasis has failed to help us understand the hidden toll of chronic stress on the body. Rather than maintaining constancy, the physiologic systems within the body fluctuate to meet demands from external forces, a state termed allostasis. In this article, we extend the concept of allostasis over the dimension of time and we define allostatic load as the cost of chronic exposure to fluctuating or heightened neural or neuroendocrine response resulting from repeated or chronic environmental challenge that an individual reacts to as being particularly stressful. [Emphasis added]

[18] CONCLUSIONS: This new formulation emphasizes the cascading relationships, beginning early in life, between environmental factors and genetic predispositions that lead to large individual differences in susceptibility to stress and, in some cases, to disease. There are now empirical studies based on this formulation, as well as new insights into mechanisms involving specific changes in neural, neuroendocrine, and immune systems. The practical implications of this formulation for clinical practice and further research are discussed.

[logan2008-4] Logan JG, Barksdale DJ. (2008) Allostasis and allostatic load: expanding the discourse on stress and cardiovascular disease. J.Clin.Nurs. 17:201-208. PMID 18578796.
Abstract:
AIM: The aim of this discursive paper is to introduce allostasis and allostatic load, which are relatively new concepts proposed to explain physiological responses to stress, and to suggest ways in which allostasis theory can be applied to the development of clinical interventions to increase resilience for producing better health outcome.

BACKGROUND: Common explanations of stress have failed adequately to explicate its association with health and chronic illness. Allostasis is the extension of the concept of homeostasis and represents the adaptation process of the complex physiological system to physical, psychosocial and environmental challenges or stress. Allostatic load is the long-term result of failed adaptation or allostasis, resulting in pathology and chronic illness.

DISCUSSION: The concepts of allostasis and allostatic load introduced the idea that external challenges initiate allostasis and chronic stress causes allostatic load that can be measured with multiple biomarkers. Finding from several studies suggests that higher allostatic load is associated with worse health outcomes. Resilience represents successful allostasis and strategies can be implemented to enhance resilience and thereby improve health outcomes.

CONCLUSIONS: This theoretical model provides a comprehensive explanation of the human body's adaptation processes in response to stress and the results of failed adaptation over time. In addition, combining the concepts of allostasis and resilience may help us to understand and implement clinical strategies better to reduce or prevent the debilitating physiological and psychological effects of chronic stress and chronic illness.

RELEVANCE TO CLINICAL PRACTICE: Clinical practice should be based on a solid theoretical foundation to improve health outcomes. Strategies to manage stress and increase resilience along with clinical interventions to manage the physiological responses to chronic stress are necessary to assist in preventing and controlling the detrimental effects of chronic disease on human life.

[20] AIM: The aim of this discursive paper is to introduce allostasis and allostatic load, which are relatively new concepts proposed to explain physiological responses to stress, and to suggest ways in which allostasis theory can be applied to the development of clinical interventions to increase resilience for producing better health outcome.

[21] BACKGROUND: Common explanations of stress have failed adequately to explicate its association with health and chronic illness. Allostasis is the extension of the concept of homeostasis and represents the adaptation process of the complex physiological system to physical, psychosocial and environmental challenges or stress. Allostatic load is the long-term result of failed adaptation or allostasis, resulting in pathology and chronic illness.

[22] DISCUSSION: The concepts of allostasis and allostatic load introduced the idea that external challenges initiate allostasis and chronic stress causes allostatic load that can be measured with multiple biomarkers. Finding from several studies suggests that higher allostatic load is associated with worse health outcomes. Resilience represents successful allostasis and strategies can be implemented to enhance resilience and thereby improve health outcomes.

[23] CONCLUSIONS: This theoretical model provides a comprehensive explanation of the human body's adaptation processes in response to stress and the results of failed adaptation over time. In addition, combining the concepts of allostasis and resilience may help us to understand and implement clinical strategies better to reduce or prevent the debilitating physiological and psychological effects of chronic stress and chronic illness.

[24] RELEVANCE TO CLINICAL PRACTICE: Clinical practice should be based on a solid theoretical foundation to improve health outcomes. Strategies to manage stress and increase resilience along with clinical interventions to manage the physiological responses to chronic stress are necessary to assist in preventing and controlling the detrimental effects of chronic disease on human life.

[mcewen&seeman-5] 5.0 ^5.1 Bruce McEwen and Teresa Seeman in collaboration with the Allostatic Load Working Group. (1999) Allostatic Load and Allostasis.

[chadwick2002-6] 6.0 ^6.1 Chadwick D., Goode J. (2002) Endocrine Facets of Ageing. John Wiley and Sons. ISBN 0471486361, ISBN 9780471486367.
”Social and medical developments have recently led to a dramatic increase in life expectancy. This has inspired the study of organismic changes associated with healthy ageing, in particular the erosion of homeostatic capabilities in multiple endocrine systems. This book reviews advances in the understanding of endocrine facets of ageing. It considers the relative magnitudes and time courses of different endocrine adaptations in the ageing human and experimental animal, addressing the influence of external factors on the rates of progression of endocrine sequelae in ageing, the mechanisms that underlie the disarray of endocrine axes in ageing, and the implications of therapeutic reconstitution of hormones in ageing. This book: Considers the mechanisms of ageing and hormonal changes that occur with age. Discusses healthy ageing and the relationships between hormonal changes and pathophysiological conditions such as atherosclerosis and age-related bone loss. Draws together contributions from basic and clinical research, to identify and stimulate promising new research directions.”

[27] ”Social and medical developments have recently led to a dramatic increase in life expectancy. This has inspired the study of organismic changes associated with healthy ageing, in particular the erosion of homeostatic capabilities in multiple endocrine systems. This book reviews advances in the understanding of endocrine facets of ageing. It considers the relative magnitudes and time courses of different endocrine adaptations in the ageing human and experimental animal, addressing the influence of external factors on the rates of progression of endocrine sequelae in ageing, the mechanisms that underlie the disarray of endocrine axes in ageing, and the implications of therapeutic reconstitution of hormones in ageing. This book: Considers the mechanisms of ageing and hormonal changes that occur with age. Discusses healthy ageing and the relationships between hormonal changes and pathophysiological conditions such as atherosclerosis and age-related bone loss. Draws together contributions from basic and clinical research, to identify and stimulate promising new research directions.”

[mcewen2000-7] McEwen BS. (2000) [10.1016/S0893-133X(99)00129-3 Allostasis and allostatic load: implications for neuropsychopharmacology.] Neuropsychopharmacology 22:108-124.
Abstract (bulleted for ease of reading): The primary hormonal mediators of the stress response, glucocorticoids and catecholamines, have both protective and damaging effects on the body. In the short run, they are essential for adaptation, maintenance of homeostasis, and survival (allostasis). Yet, over longer time intervals, they exact a cost (allostatic load) that can accelerate disease processes.

The concepts of allostasis and allostatic load center around the brain as interpreter and responder to environmental challenges and as a target of those challenges.

In anxiety disorders, depressive illness, hostile and aggressive states, substance abuse, and post-traumatic stress disorder (PTSD), allostatic load takes the form of chemical imbalances as well as perturbations in the diurnal rhythm, and, in some cases, atrophy of brain structures.

In addition, growing evidence indicates that depressive illness and hostility are both associated with cardiovascular disease (CVD) and other systemic disorders. A major risk factor for these conditions is early childhood experiences of abuse and neglect that increase allostatic load later in life and lead individuals into social isolation, hostility, depression, and conditions like extreme obesity and CVD. Animal models support the notion of lifelong influences of early experience on stress hormone reactivity.

Whereas, depression and childhood abuse and neglect tend to be more prevalent in individuals at the lower end of the socioeconomic ladder, cardiovascular and other diseases follow a gradient across the full range of socioeconomic status (SES).

An SES gradient is also evident for measures of allostatic load. Wide-ranging SES gradients have also been described for substance abuse and affective and anxiety disorders as a function of education. These aspects are discussed as important, emerging public health issues where the brain plays a key role.

[29] Abstract (bulleted for ease of reading): The primary hormonal mediators of the stress response, glucocorticoids and catecholamines, have both protective and damaging effects on the body. In the short run, they are essential for adaptation, maintenance of homeostasis, and survival (allostasis). Yet, over longer time intervals, they exact a cost (allostatic load) that can accelerate disease processes.

[30] The concepts of allostasis and allostatic load center around the brain as interpreter and responder to environmental challenges and as a target of those challenges.

[31] In anxiety disorders, depressive illness, hostile and aggressive states, substance abuse, and post-traumatic stress disorder (PTSD), allostatic load takes the form of chemical imbalances as well as perturbations in the diurnal rhythm, and, in some cases, atrophy of brain structures.

[32] In addition, growing evidence indicates that depressive illness and hostility are both associated with cardiovascular disease (CVD) and other systemic disorders. A major risk factor for these conditions is early childhood experiences of abuse and neglect that increase allostatic load later in life and lead individuals into social isolation, hostility, depression, and conditions like extreme obesity and CVD. Animal models support the notion of lifelong influences of early experience on stress hormone reactivity.

[33] Whereas, depression and childhood abuse and neglect tend to be more prevalent in individuals at the lower end of the socioeconomic ladder, cardiovascular and other diseases follow a gradient across the full range of socioeconomic status (SES).

[34] An SES gradient is also evident for measures of allostatic load. Wide-ranging SES gradients have also been described for substance abuse and affective and anxiety disorders as a function of education. These aspects are discussed as important, emerging public health issues where the brain plays a key role.

[mcewen2007-8] McEwen BS. (2007) Physiology and neurobiology of stress and adaptation: central role of the brain. Physiol Rev 87:873-904.
Abstract (bulleted for ease of reading):

The brain is the key organ of the response to stress because it determines what is threatening and, therefore, potentially stressful, as well as the physiological and behavioral responses which can be either adaptive or damaging.

Stress involves two-way communication between the brain and the cardiovascular, immune, and other systems via neural and endocrine mechanisms.

Beyond the "flight-or-fight" response to acute stress, there are events in daily life that produce a type of chronic stress and lead over time to wear and tear on the body ("allostatic load").

Yet, hormones associated with stress protect the body in the short-run and promote adaptation ("allostasis").

The brain is a target of stress, and the hippocampus was the first brain region, besides the hypothalamus, to be recognized as a target of glucocorticoids.

Stress and stress hormones produce both adaptive and maladaptive effects on this brain region throughout the life course.

Early life events influence life-long patterns of emotionality and stress responsiveness and alter the rate of brain and body aging.

The hippocampus, amygdala, and prefrontal cortex undergo stress-induced structural remodeling, which alters behavioral and physiological responses.

As an adjunct to pharmaceutical therapy, social and behavioral interventions such as regular physical activity and social support reduce the chronic stress burden and benefit brain and body health and resilience

[36] Abstract (bulleted for ease of reading):

[37] The brain is the key organ of the response to stress because it determines what is threatening and, therefore, potentially stressful, as well as the physiological and behavioral responses which can be either adaptive or damaging.

[38] Stress involves two-way communication between the brain and the cardiovascular, immune, and other systems via neural and endocrine mechanisms.

[39] Beyond the "flight-or-fight" response to acute stress, there are events in daily life that produce a type of chronic stress and lead over time to wear and tear on the body ("allostatic load").

[40] Yet, hormones associated with stress protect the body in the short-run and promote adaptation ("allostasis").

[41] The brain is a target of stress, and the hippocampus was the first brain region, besides the hypothalamus, to be recognized as a target of glucocorticoids.

[42] Stress and stress hormones produce both adaptive and maladaptive effects on this brain region throughout the life course.

[43] Early life events influence life-long patterns of emotionality and stress responsiveness and alter the rate of brain and body aging.

[44] The hippocampus, amygdala, and prefrontal cortex undergo stress-induced structural remodeling, which alters behavioral and physiological responses.

[45] As an adjunct to pharmaceutical therapy, social and behavioral interventions such as regular physical activity and social support reduce the chronic stress burden and benefit brain and body health and resilience

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@@ Line 70: / Line 70: @@
 :*In addition, growing evidence indicates that depressive illness and hostility are both associated with cardiovascular disease (CVD) and other systemic disorders. A major risk factor for these conditions is early childhood experiences of abuse and neglect that increase allostatic load later in life and lead individuals into social isolation, hostility, depression, and conditions like extreme obesity and CVD. Animal models support the notion of lifelong influences of early experience on stress hormone reactivity.
 :*Whereas, depression and childhood abuse and neglect tend to be more prevalent in individuals at the lower end of the socioeconomic ladder, cardiovascular and other diseases follow a gradient across the full range of socioeconomic status (SES).
-:*An SES gradient is also evident for measures of allostatic load. Wide-ranging SES gradients have also been described for substance abuse and affective and anxiety disorders as a function of education. These aspects are discussed as important, emerging public health issues where the brain plays a key role.</ref> <ref name=mcewen2007>McEwen BS. (2007) Physiology and neurobiology of stress and adaptation: central role of the brain. ''Physiol Rev'' 87:873-904.</ref>
+:*An SES gradient is also evident for measures of allostatic load. Wide-ranging SES gradients have also been described for substance abuse and affective and anxiety disorders as a function of education. These aspects are discussed as important, emerging public health issues where the brain plays a key role.</ref> <ref name=mcewen2007>McEwen BS. (2007) Physiology and neurobiology of stress and adaptation: central role of the brain. ''Physiol Rev'' 87:873-904.
+*'''<u>Abstract (bulleted for ease of reading):</u>'''
+:*The brain is the key organ of the response to stress because it determines what is threatening and, therefore, potentially stressful, as well as the physiological and behavioral responses which can be either adaptive or damaging.
+:*Stress involves two-way communication between the brain and the cardiovascular, immune, and other systems via neural and endocrine mechanisms.
+:*Beyond the "flight-or-fight" response to acute stress, there are events in daily life that produce a type of chronic stress and lead over time to wear and tear on the body ("allostatic load").
+:*Yet, hormones associated with stress protect the body in the short-run and promote adaptation ("allostasis").
+:*The brain is a target of stress, and the hippocampus was the first brain region, besides the hypothalamus, to be recognized as a target of glucocorticoids.
+:*Stress and stress hormones produce both adaptive and maladaptive effects on this brain region throughout the life course.
+:*Early life events influence life-long patterns of emotionality and stress responsiveness and alter the rate of brain and body aging.
+:*The hippocampus, amygdala, and prefrontal cortex undergo stress-induced structural remodeling, which alters behavioral and physiological responses.
+:*As an adjunct to pharmaceutical therapy, social and behavioral interventions such as regular physical activity and social support reduce the chronic stress burden and benefit brain and body health and resilience</ref>
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Allostasis and allostatic load: Difference between revisions

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Allostasis and allostatic load: Difference between revisions

Revision as of 20:20, 12 November 2008

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To learn more about allostasis and allostatic load

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