Blushing
Encyclopedia
Blushing refers to the involuntary reddening of a person's face
due to embarrassment
or emotional stress
, though it has been known to come from being lovestruck, or from some kind of romantic stimulation. It is thought that blushing is the result of an overactive sympathetic nervous system
. Severe blushing is common in people who suffer social anxiety
in which the person experiences extreme and persistent anxiety in social and performance situations.
Blushing is generally distinguished, despite a close physiological relation, from flushing
, which is more intensive and extends over more of the body, and seldom has a mental source.
If redness persists for abnormal amounts of time after blushing, then it may be considered an early sign of rosacea
. Idiopathic craniofacial erythema
is a medical condition where a person blushes strongly with little or no provocation. Just about any situation can bring on intense blushing and it may take one or two minutes for the blush to disappear. Severe blushing can make it difficult for the person to feel comfortable in either social or professional situations. People who have social phobia are particularly prone to idiopathic craniofacial erythema. Psychological treatments and medication can help control blushing.
Some people are overly sensitive to emotional stress. Given a stimulus such as embarrassment, the person's sympathetic nervous system will cause blood vessels to open wide, flooding the skin with blood and resulting in reddening of the face. In some people, the ears, neck and upper chest may also blush. As well as causing redness, blushing can sometimes make the affected area feel hot.
Erythrophobia is the fear of blushing, from , red, and , fear, literally "fear of redness.".
s that have tiny muscles inside the walls. These muscles are under the control of the sympathetic nervous system
. Blood flow
to the skin provides nutrition to the skin and regulates body heat
. Usually, the muscles are partly contracted (squeezed). If the muscles contract more than normal, for example in cold weather, the blood vessels also contract so that less blood passes through them, and also reduces the loss of body heat. If the blood flow is restricted, the skin becomes pale and white. When the muscles are completely relaxed, for example in warm weather, the blood vessels dilate (widen). This allows more blood to pass through the skin resulting in the body radiating more heat thus making the skin appear red.
The circulatory system
of the skin contains three major types of blood vessels: (Rowell. 1993; Rowell. 1974)
Along with this basal tone, all resistance vessels in the skin receive a tonic outflow from sympathetic vasoconstrictor fibers. This tonic outflow is inversely associated with body temperature. Vasodilation therefore occurs passively in resistance vessels the (alpha-adrenergic) vasoconstrictor tone decreases. Furthermore, an active neurogenic vasodilation must be assumed in the human skin. However, it is not clear if this vasodilation is mediated by specific vasodilator nerve fibers or if neuro-humoral effects are involved that are associated with the sympathetic cholinergic activation of sweat glands (Rowell. 1993; Lembeck & Holzbauer. 1988). Although some experiments lead to the conclusion that sympathetic outflow is involved in facial vasodilation 40 years of research have not clarified the mechanism behind active vasodilation.
Cutaneous veins also are richly innervated with sympathetic vasoconstrictor fibers. The effect of activation of the outflow of these fibers is reduced by local cooling. In addition, cutaneous veins are temporarily reactive to various other stimuli. Each of the following can cause remarkably intense venoconstriction without obvious value to the organism: emotional stimuli (e.g. startle, apprehension, discomfort), hyperventilation, deep inspiration, and the Valsalva maneuver
(Rowell. 1974).
In resistance vessels, increased pressure mainly increases flow per time unit. In the cutaneous venous plexus with its generally slow flow rate, pressure mainly influences volume. Because of its enormous volume variability and its large potential capacity the venous plexus is believed to determine skin color (Rowell. 1993; Mellander, Andersson, Afzelius, & Hellstrand. 1982; Rowell. 1974). Since pronounced blushing is also characterized by a deep reddening of the skin, vasodilation of the venous plexus is probably the physical mechanism underlying it. Emotional blushing is only visible or apparent in a specific area called the blush region. The area is restricted to the face, ears, neck, and in some rare cases the upper body. Two main hypotheses to explain this regional restriction have been proposed. One is that vasodilation takes place throughout the entire skin of the body but is only visible in the blush region due to special anatomical structure of that region. The second is that a specific form of vasodilation takes place exclusively in the blush region. It is likely, that a combination of these two factors accounts for blushing.
Evidence for special vasodilation
mechanisms was reported by Mellander and his colleagues (Mellander, Andersson, Afzelius, & Hellstrand. 1982). They studied buccal segments of the human facial veins in vitro
. Unlike veins from other areas of the skin, facial veins responded with an active myogenic
contraction to passive stretch and were therefore able to develop an intrinsic basal tone. Additionally Mellander et al. showed that the veins in this specific area were also supplied with beta-adrenoceptors in addition to the common alpha-adrenoceptors. These beta-adrenoceptors could exert a dilator mechanism on the above-described basal tone of the facial cutaneous venous plexus
. Mellander and his colleagues propose that this mechanism is involved in emotional blushing. Drummond has partially confirmed this effect by pharmacological blocking experiments (Drummond. 1997). In a number of trials, he blocked both alpha-adrenergic receptor
s (with phentolamine) and beta-adrenergic receptors (with propranolol introduced
transcutaneously by iontophoresis). Blushing was measured at the forehead using a dual channel laser Doppler flowmeter. Subjects were undergraduate students divided into frequent and infrequent blushers according to self-report. Their mean age was 22.9 years, which is especially favorable for assessing blushing, since young subjects are more likely to blush and blush more intensively. The subjects underwent several procedures, one of which was designed to produce blushing. Alpha-adrenergic blockade with phentolamine had no influence on the amount of blushing in frequent or in infrequent blushers, indicating that release of sympathetic vasoconstrictor tone does not substantially influence blushing. This result was expected since vasoconstrictor tone in the facial area is known to be generally low (van der Meer. 1985). Beta-adrenergic blockade with propranolol on the other hand decreased blushing in both frequent and infrequent blushers. However, despite complete blockade, blood flow still increased
substantially during the embarrassment and blushing inducing procedure. Additional vasodilator mechanisms must therefore be involved.
devoted Chapter 13 of his 1872 The Expression of the Emotions in Man and Animals
to complex emotional states including self-attention, shame, shyness, modesty, and blushing. He described blushing as "... the most peculiar and most human of all expressions."
Several different psychological and psycho-physiological mechanisms for blushing have been hypothesized by Crozier (2010). It has also been suggested that blushing and flushing are the visible manifestations of the physiological rebound of the basic instinctual fight/flight
mechanism, when physical action is not possible.
Face
The face is a central sense organ complex, for those animals that have one, normally on the ventral surface of the head, and can, depending on the definition in the human case, include the hair, forehead, eyebrow, eyelashes, eyes, nose, ears, cheeks, mouth, lips, philtrum, temple, teeth, skin, and...
due to embarrassment
Embarrassment
Embarrassment is an emotional state of intense discomfort with oneself, experienced upon having a socially unacceptable act or condition witnessed by or revealed to others. Usually some amount of loss of honour or dignity is involved, but how much and the type depends on the embarrassing situation...
or emotional stress
Stress (biology)
Stress is a term in psychology and biology, borrowed from physics and engineering and first used in the biological context in the 1930s, which has in more recent decades become commonly used in popular parlance...
, though it has been known to come from being lovestruck, or from some kind of romantic stimulation. It is thought that blushing is the result of an overactive sympathetic nervous system
Sympathetic nervous system
The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...
. Severe blushing is common in people who suffer social anxiety
Social anxiety
Social anxiety is anxiety about social situations, interactions with others, and being evaluated or scrutinized by other people...
in which the person experiences extreme and persistent anxiety in social and performance situations.
Blushing is generally distinguished, despite a close physiological relation, from flushing
Flushing (physiology)
For a person to flush is to become markedly red in the face and often other areas of the skin, from various physiological conditions. Flushing is generally distinguished, despite a close physiological relation between them, from blushing, which is milder, generally restricted to the face, cheeks or...
, which is more intensive and extends over more of the body, and seldom has a mental source.
If redness persists for abnormal amounts of time after blushing, then it may be considered an early sign of rosacea
Rosacea
Rosacea is a chronic condition characterized by facial erythema . Pimples are sometimes included as part of the definition. Unless it affects the eyes, it is typically a harmless cosmetic condition...
. Idiopathic craniofacial erythema
Idiopathic craniofacial erythema
Idiopathic Craniofacial Erythema is a medical condition characterised by severe, uncontrollable, and frequently unprovoked, facial blushing.Blushing can occur at any time and is frequently triggered by even mundane events, such as, talking to friends, paying for goods in a shop or asking for...
is a medical condition where a person blushes strongly with little or no provocation. Just about any situation can bring on intense blushing and it may take one or two minutes for the blush to disappear. Severe blushing can make it difficult for the person to feel comfortable in either social or professional situations. People who have social phobia are particularly prone to idiopathic craniofacial erythema. Psychological treatments and medication can help control blushing.
Some people are overly sensitive to emotional stress. Given a stimulus such as embarrassment, the person's sympathetic nervous system will cause blood vessels to open wide, flooding the skin with blood and resulting in reddening of the face. In some people, the ears, neck and upper chest may also blush. As well as causing redness, blushing can sometimes make the affected area feel hot.
Erythrophobia is the fear of blushing, from , red, and , fear, literally "fear of redness.".
Blood vessels
The skin contains a network of small blood vesselBlood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...
s that have tiny muscles inside the walls. These muscles are under the control of the sympathetic nervous system
Sympathetic nervous system
The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...
. Blood flow
Blood flow
Blood flow is the continuous running of blood in the cardiovascular system.The human body is made up of several processes all carrying out various functions. We have the gastrointestinal system which aids the digestion and the absorption of food...
to the skin provides nutrition to the skin and regulates body heat
Thermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different...
. Usually, the muscles are partly contracted (squeezed). If the muscles contract more than normal, for example in cold weather, the blood vessels also contract so that less blood passes through them, and also reduces the loss of body heat. If the blood flow is restricted, the skin becomes pale and white. When the muscles are completely relaxed, for example in warm weather, the blood vessels dilate (widen). This allows more blood to pass through the skin resulting in the body radiating more heat thus making the skin appear red.
The circulatory system
Circulatory system
The circulatory system is an organ system that passes nutrients , gases, hormones, blood cells, etc...
of the skin contains three major types of blood vessels: (Rowell. 1993; Rowell. 1974)
- Arteries, capillaries and veins that serve mainly nutrition needs.
- The subcutaneous venous plexus that plays a major role in the conduction of heat and contains a major fraction of the cutaneous blood volume.
- Arteriovenous anastomoses which can be found in areas of the body especially exposed to maximal cooling like the hands, feet, nose, lips and ears. These areas are called apical structures and are richly innervated. The anastomoses connect cutaneous arterioles and venules directly, playing an important role in the reduction of blood flow in a cold environment
Regulation of blood flow in the skin
Blood flow in the cutaneous resistance vessels and the subcutaneous venous plexus are both neurally and locally regulated. However, there are some important differences. One is, that cutaneous resistance vessels exhibit a basal tone independently of innervation in reaction to passive stretch induced by blood pressure (Rowell. 1974). This intrinsic basal tone is normally absent in cutaneous capacitance vessels .Along with this basal tone, all resistance vessels in the skin receive a tonic outflow from sympathetic vasoconstrictor fibers. This tonic outflow is inversely associated with body temperature. Vasodilation therefore occurs passively in resistance vessels the (alpha-adrenergic) vasoconstrictor tone decreases. Furthermore, an active neurogenic vasodilation must be assumed in the human skin. However, it is not clear if this vasodilation is mediated by specific vasodilator nerve fibers or if neuro-humoral effects are involved that are associated with the sympathetic cholinergic activation of sweat glands (Rowell. 1993; Lembeck & Holzbauer. 1988). Although some experiments lead to the conclusion that sympathetic outflow is involved in facial vasodilation 40 years of research have not clarified the mechanism behind active vasodilation.
Cutaneous veins also are richly innervated with sympathetic vasoconstrictor fibers. The effect of activation of the outflow of these fibers is reduced by local cooling. In addition, cutaneous veins are temporarily reactive to various other stimuli. Each of the following can cause remarkably intense venoconstriction without obvious value to the organism: emotional stimuli (e.g. startle, apprehension, discomfort), hyperventilation, deep inspiration, and the Valsalva maneuver
Valsalva maneuver
The Valsalva maneuver or Valsalva manoeuvre is performed by moderately forceful attempted exhalation against a closed airway, usually done by closing one's mouth and pinching one's nose shut...
(Rowell. 1974).
In resistance vessels, increased pressure mainly increases flow per time unit. In the cutaneous venous plexus with its generally slow flow rate, pressure mainly influences volume. Because of its enormous volume variability and its large potential capacity the venous plexus is believed to determine skin color (Rowell. 1993; Mellander, Andersson, Afzelius, & Hellstrand. 1982; Rowell. 1974). Since pronounced blushing is also characterized by a deep reddening of the skin, vasodilation of the venous plexus is probably the physical mechanism underlying it. Emotional blushing is only visible or apparent in a specific area called the blush region. The area is restricted to the face, ears, neck, and in some rare cases the upper body. Two main hypotheses to explain this regional restriction have been proposed. One is that vasodilation takes place throughout the entire skin of the body but is only visible in the blush region due to special anatomical structure of that region. The second is that a specific form of vasodilation takes place exclusively in the blush region. It is likely, that a combination of these two factors accounts for blushing.
Physiology of blushing
There is evidence that the blushing region is anatomically different in structure. The facial skin, for example, has more capillary loops per unit area and generally more vessels per unit volume than other skin areas. In addition, blood vessels of the cheek are wider in diameter, are nearer the surface, and visibility is less diminished by tissue fluid. These specific characteristics of the architecture of the facial vessels led Wilkin in an overview of possible causes of facial flushing to the following conclusion: "[...] increased capacity and greater visibility can account for the limited distribution of flushing".Evidence for special vasodilation
Vasodilation
Vasodilation refers to the widening of blood vessels resulting from relaxation of smooth muscle cells within the vessel walls, particularly in the large arteries, smaller arterioles and large veins. The process is essentially the opposite of vasoconstriction, or the narrowing of blood vessels. When...
mechanisms was reported by Mellander and his colleagues (Mellander, Andersson, Afzelius, & Hellstrand. 1982). They studied buccal segments of the human facial veins in vitro
In vitro
In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...
. Unlike veins from other areas of the skin, facial veins responded with an active myogenic
Myogenic
Myogenic contraction refers to a contraction initiated by the myocyte cell itself instead of an outside occurrence or stimulus such as nerve innervation.- Unstable Membrane Potentials :...
contraction to passive stretch and were therefore able to develop an intrinsic basal tone. Additionally Mellander et al. showed that the veins in this specific area were also supplied with beta-adrenoceptors in addition to the common alpha-adrenoceptors. These beta-adrenoceptors could exert a dilator mechanism on the above-described basal tone of the facial cutaneous venous plexus
Venous plexus
A venous plexus is a congregation of multiple veins.Examples of venous plexuses are:* Vesical venous plexus* Vaginal venous plexus* Uterine venous plexus*Pterygoid plexus...
. Mellander and his colleagues propose that this mechanism is involved in emotional blushing. Drummond has partially confirmed this effect by pharmacological blocking experiments (Drummond. 1997). In a number of trials, he blocked both alpha-adrenergic receptor
Adrenergic receptor
The adrenergic receptors are a class of metabotropic G protein-coupled receptors that are targets of the catecholamines, especially noradrenaline and adrenaline ....
s (with phentolamine) and beta-adrenergic receptors (with propranolol introduced
transcutaneously by iontophoresis). Blushing was measured at the forehead using a dual channel laser Doppler flowmeter. Subjects were undergraduate students divided into frequent and infrequent blushers according to self-report. Their mean age was 22.9 years, which is especially favorable for assessing blushing, since young subjects are more likely to blush and blush more intensively. The subjects underwent several procedures, one of which was designed to produce blushing. Alpha-adrenergic blockade with phentolamine had no influence on the amount of blushing in frequent or in infrequent blushers, indicating that release of sympathetic vasoconstrictor tone does not substantially influence blushing. This result was expected since vasoconstrictor tone in the facial area is known to be generally low (van der Meer. 1985). Beta-adrenergic blockade with propranolol on the other hand decreased blushing in both frequent and infrequent blushers. However, despite complete blockade, blood flow still increased
substantially during the embarrassment and blushing inducing procedure. Additional vasodilator mechanisms must therefore be involved.
Psychology of blushing
Charles DarwinCharles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
devoted Chapter 13 of his 1872 The Expression of the Emotions in Man and Animals
The Expression of the Emotions in Man and Animals
The Expression of the Emotions in Man and Animals is a book by Charles Darwin, published in 1872, concerning genetically determined aspects of behaviour. It was published thirteen years after On The Origin of Species and is, along with his 1871 book The Descent of Man, Darwin's main consideration...
to complex emotional states including self-attention, shame, shyness, modesty, and blushing. He described blushing as "... the most peculiar and most human of all expressions."
Several different psychological and psycho-physiological mechanisms for blushing have been hypothesized by Crozier (2010). It has also been suggested that blushing and flushing are the visible manifestations of the physiological rebound of the basic instinctual fight/flight
Fight-or-flight response
The fight-or-flight response was first described by Walter Bradford Cannon....
mechanism, when physical action is not possible.
Further reading
- Crozier, W. R., Blushing and the Social Emotions: The Self Unmasked, Basingstoke, Palgrave Macmillan, 2006. ISBN 1403946752
- Miller, R. S., Embarrassment: Poise and Peril in Everyday Life, Guilford Press, 1997. ISBN 157230247
- Jadresic, E., When Blushing Hurts: Overcoming Abnormal Facial Blushing, iUniverse, 2008. ISBN 978-0595521579.
- Daniels B. W Understanding Uncontrollable Facial Blushing", Neptune, Elizabeth Stewart, 2010.