Panic Attacks, Hyperventilation, and Hypertension

Thomas Pickering, MD, DPhil


The role of anxiety and tension in hypertension has long been a subject of debate, and our patients commonly think that the tension part of the word in hypertension refers to a psychic rather than a physical phenomenon. Although hypertension is officially regarded as being an asymptomatic condition, anyone who spends time seeing hypertensive patients knows that this typically is not so. Patients who experience symptoms from whatever cause, are more likely to seek medical care and show up in hypertension clinics as well as other medical clinics. The symptoms are often vague and difficult to relate to any specific cause. In 1997, Dr. Norman Kaplan published a paper entitled "Anxiety-Induced Hyperventilation: A Common Cause of Symptoms in Patients With Hypertension," in which he described a series of 300 patients who were referred to him because their hypertension was difficult to treat.[1] The constellation of symptoms that many of these patients described include paresthesiae, lightheadedness, dizziness, palpitations, and headache. The case for attributing these to hyperventilation was made in about one third of the patients by establishing that voluntary hyperventilation replicated the symptoms and that rebreathing into a paper bag made them disappear.

A related and overlapping set of symptoms is panic attacks; a recent paper has described an association between those symptoms and hypertension. A survey of a general practice in England, which included both a normotensive and a hypertensive group, and a hospital hypertension clinic in England[2] found a significantly higher prevalence of panic attacks in hypertensive than in normotensive patients, but the difference was not huge (30% vs. 19%). What I found astonishing about these figures is how common panic disorder was in all three groups. Criteria for diagnosing a panic attack included a discrete period of fear or discomfort plus dyspnea, dizziness, palpitations, trembling, etc. Interestingly, the prevalence was the same in the hypertensives attending the primary care clinic as in the hospital clinic, suggesting the higher incidence in hypertensives was not just due to a referral bias. In this study the hypertensives scored higher on anxiety scores than the normotensives. It was not possible to say whether the hypertension preceded the panic attacks or vice versa, although the hypertension was typically diagnosed before the panic attacks, which may simply reflect the lack of recognition of the latter. Both hyperventilation and panic attacks appear to be more common in women than men.[2]

Papers in the medical and psychiatric literature state that hyperventilation causes vasoconstriction and increases of blood pressure, even though a classic early study of the hemodynamic effects of voluntary hyperventilation concluded that hyperventilating for one minute lowered peripheral resistance by 45%, and mean blood pressure by 23 mm Hg.[3] So, who is right? The answer is possibly both. A recent study of the effects of hyperventilation compared the blood pressure and heart rate changes in patients with panic disorder and normal controls.[4] In the normal subjects both systolic and diastolic pressure decreased, while in the panic patients both systolic and diastolic increased. In addition, about one third of the panic patients reported symptoms of panic during hyperventilation, whereas none of the controls reported symptoms. The explanation may be that hyperventilation itself does lower blood pressure, and it is only when panic is superimposed that the pressure goes up.

Ambulatory monitoring studies have shown that naturally occurring panic attacks do cause a transient elevation of blood pressure,[5] and may cause the patient to go to the emergency room, where the setting is likely to further increase the blood pressure. The finding of a high blood pressure in this setting often leads to a work-up for pheochromocytoma, which is typically negative. However, the last patient that I saw with a pheochromocytoma had been treated for both panic attacks and seizures for 10 years. Her symptoms were very brief and until she had an episode when she happened to be in the hospital, her blood pressure had not been recorded during an episode, so the penny never dropped. Following successful removal of her tumor, the symptoms ceased.

Panic attacks and hyperventilation are important to recognize and often under-diagnosed, even though they frequently lead patients to seek medical advice. These encounters are often frustrating not only for the patient but also for the physician who typically has neither the time nor the skills to make the diagnosis. Greater awareness of the high prevalence and high economic cost of these syndromes cannot only avoid unnecessary testing, but can also lead to specific treatments, such as the use of antidepressants and cognitive behavioral therapy, both of which have been shown to be effective.[6]


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