Some medical researchers seek to find the basis of anxiety attacks in their study of biology and biochemistry. They are looking for evidence that a genetic trait or abnormality directly causes anxiety attacks.
Much of the discussion of the possible existence of a genetic problem centers on the role of unusually high blood-lactate levels in triggering physical feelings like shakiness, dizziness, and numbness and tingling of the skin.
Lactate is a normal byproduct of the conversion of the sugar glycogen to energy by muscle cells. The more work our muscles do, the more lactate they will discharge into the bloodstream. A very large amount of lactate in the blood is thought to increase nervous reactivity by binding with calcium molecules and thus interfering with the normal functioning of calcium in the transmission of nerve impulses from nerve fiber to nerve fiber in the central nervous system.
Dr. Ferris N. Pitts, Jr., found that injections of extra lactate into the bloodstream produced paresthesia, “a numbness and tingling of the skin that is usually caused by a low level of calcium in the tissues,” in all 24 subjects of a study he described in 1969 in an article in Scientific American entitled “The Biochemistry of Anxiety.” In addition, the injections produced reports of a wide array of feelings (including tremor, shakiness, dizziness, palpitation, cold, nervousness, nervous chill, and weakness) from the 14 anxiety patients and, to a lesser degree, from the 10 “normal” controls in the study.
During the injection of the lactate, which took 20 minutes, 13 of the anxiety patients and 2 of the control subjects had “typical acute anxiety attacks.” When calcium was added to the lactate solution, fewer symptoms were reported and “there was no significant difference in the extent to which each symptom was reported by the two groups.”
Pitts and his colleague James N. McClure, Jr., concluded that “a high concentration of lactate ion can produce some anxiety symptoms in almost anyone, that it regularly produces anxiety attacks in patients but not in controls, and that calcium ion largely prevents the symptoms in both patients and controls.”
Pitts observed no difference between the anxiety patients and the control subjects in their ability to clear lactate from the blood: “In all our subjects the excess lactate from the infusions was removed normally by the liver in 60 to 90 minutes.”
In a recent book called The Anxiety Disease, psychiatrist David V. Sheehan contends that anxiety disorders stem from “a biological and probably a biochemical disorder.” To support the idea that there is a possible “genetic weakness” in anxious people, Sheehan cites a 1966 study by Pitts, which he describes as follows:
In 1966 . . . Pitts found that giving an intravenous infusion of sodium lactate to victims of this disease brought on spells of panic just like their original symptoms. It is possible to turn the condition on simply by injecting this substance, which is produced in everyone’s body in response to exercise. If you give sodium lactate to normal individuals, nothing happens; with anxiety disease victims, turning off the lactate infusions stops the symptoms.
The conclusion Sheehan draws from this 1966 study does not seem to accord with that offered by Pitts himself in the 1969 article, in which he said that something does happen when you give sodium lactate to normal individuals. All of his subjects experienced numbness and tingling of the skin, and many of them experienced other “anxiety symptoms.” Pitts and McClure’s findings are consistent with a different interpretation: People who suffer anxiety attacks are simply normal people under prolonged stress. Their bodies are overproducing adrenaline (epinephrine) and, as a consequence, the muscles in their bodies continuously contract. The tendency of anxious people to keep their muscles contracted (which was scientifically documented in 1929 by Dr. Edmund Jacobson, the creator of the progressive-relaxation technique) produces the excess lactate that is believed to deplete the amount of calcium available at nerve synapses, leading to over reactivity—especially when additional lactate is injected into the bloodstream.
This view is bolstered somewhat by a finding reported by cardiologist Herbert Benson in the Relaxation Response:
If increased lactate is instrumental in producing regular attacks of anxiety, the finding of low levels of lactate in meditators is consistent with their reports of significantly more relaxed, less anxious feelings. Blood-lactate levels fall rapidly within the first ten minutes of meditation, and remain at extremely low levels during meditation. Though the reason for decreased lactate is uncertain, it is consistent with decreased activity of the sympathetic nervous system.
There may be another biochemical link between psycho-logical stress and the sudden, unexplained experience of acute anxiety. Anxious people typically tend to hold their breath for a few seconds at a time or to overbreathe (hyperventilate) at least slightly when they are distressed and, particularly, when they are startled. These habits disrupt the natural rhythm of breathing and, if strong enough, play havoc with the body’s ability to maintain optimum levels of oxygen and carbon dioxide in the blood. The resulting series of chemical changes in the brain and body may trigger the heightened feelings of physiological distress that constitute anxiety symptoms.
The balanced, relaxed posture and rhythmical abdominal breathing that characterize meditation (1) may reduce the blood-lactate level by reducing overall muscular tension, and (2) may help maintain optimum levels of oxygen and carbon dioxide in the blood by eliminating jerky, arrhythmical breathing.
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