Stress can either be mental or physical. Mental stress, the type we address in this article, is a situation perceived as an uncontrollable threat to an individual’s well-being. Our responses to stress have evolved because it is critical to survival in a dangerous and hostile environment. These responses prepare one for either fight or flight. So how does stress affect the cardiovascular system?
Mental stress is a risk factor for cardiovascular disease, or CVD, according to both experimental and clinical evidence. Mental stress may cause:
- Increased sympathetic activity, or the fight or flight response, leading to increased blood pressure levels and pulse rates.
- Reduced insulin sensitivity or intolerance to glucose and diabetes.
- Increased blood clotting and blood vessel dysfunction.
- Reduced blood flow to the heart.
These findings suggest that mental stress may trigger the clinical events of coronary heart disease, particularly in the presence of advanced hardening of the coronary or heart arteries also known as coronary atherosclerosis.
Role of Stress in Diabetes and High Blood Pressure
The effect of mental stress on increased glucose intolerance or insulin insensitivity can lead to diabetes. Diabetes raises the risk of coronary heart disease; and the excess risk associated with mental stress may be, in part, made worse by diabetes. However, there are few medical studies that actually examine how much mental stress contributes to mortality as well as the occurrence of CVD.
One of the potential reasons for the excess risk of heart attack associated with mental stress is the effect this stress has on increased blood pressure levels and heart rates by increasing the body’s fight or flight activities.
People who experience more elevated blood pressure response to mental stress tend to live with more atherosclerosis in the arteries that supply the heart with oxygen and nutrients it needs to pump. Studies show that these patients continue to experience ongoing hardening of these arteries.
Stress can raise blood pressure both immediately and chronically. Immediate stress, which is often called acute stress, is the tension one feels during an episode of fear or anxiety. Acute stress can cause a rapid and large increase in blood pressure and heart rate. But, it is usually short-lived. Patients who already have high blood pressure, often complain of symptoms such as dizziness, palpitations, and headache, which are also caused by anxiety. Panic attacks are common in the general population, but are more frequently seen in individuals with high blood pressure.
The role of chronic stress in contributing to high blood pressure is less clear — partly because chronic stress is so hard to measure. The perception of stress is largely subjective and experiences that may be stressful for one person may be much less so for another.
There is consistent evidence that “stressed” people in impoverished environments, or those who move from a traditional structured environment to a less secure urban lifestyle, are likely to show an increase in blood pressure. Personality factors such as time urgency and hostility may also be important. After the terrorist attacks of September 11, 2001, there was evidence of a nationwide increase in blood pressure (of approximately two mm Hg) during the month after the attack.
One of the best-studied models of chronic mental stress is exposure to job strain, defined by a combination of high demands and low control at work. Men who work in high-strain jobs have elevated blood pressure not only at work but also during sleep, suggesting that chronic stress can reset our blood pressure to a higher level. Women are less susceptible to this effect.
Broken Heart Syndrome
Takotsubo cardiomyopathy, or broken heart syndrome, is a disease of the heart muscle — not the vessels — often caused by stress. This sudden and temporary weakening of muscle in the heart can be triggered by emotional stress such as the death of a loved one, a break-up, or constant anxiety. Broken heart syndrome is a well-recognized cause of acute heart failure, lethal rhythm problems, and heart rupture. Some symptoms of the syndrome include congestive heart failure and heart attack originating in the front wall of the heart. Patients who come to the hospital exhibiting these indicators receive a coronary angiogram, which examines the blood vessels leading to the heart. When the angiogram does not reveal any significant blockages that would cause a heart attack, doctors often find that the patient has broken heart syndrome, instead. Provided that the individual survives their initial presentation, their heart function improves within two months. Takotsubo cardiomyopathy is more commonly seen in post-menopausal women.
Treatment is generally supportive in nature. Although patients with Takotsubo heart disease may actually have low blood pressure when they are seen, treatment with medicines to increase the blood pressure will usually make the disease worse. Since the disease is due to a high-adrenaline state, patients should not be given drugs to increase heart activity. Treatment recommendations include intra-aortic balloon pump, fluids, and blood pressure medications such as beta blockers or calcium channel blockers.
Despite the grave, initial presentation in some patients, most survive the initial acute event with a very low rate of in-hospital death or complications. Patients can expect a favorable outcome once recovery from the acute stage of the syndrome begins; and the long-term prognosis is excellent. Even when the heart’s ability to pump is heavily compromised at first, it typically improves within the first few days and normalizes within a few months.
Fortunately, one can increase resistance to mental stress by strengthening physical health. Ways to do this include:
- Exercise regularly. Physical activity plays a key role in reducing and preventing the effects of stress. Get at least 30 minutes of exercise, three times per week.
- Eat a healthy diet. Diets should be rich in fruits, vegetables, and unprocessed foods. Reduce caffeine and sugar.
- Get enough sleep.
- Use relaxation therapy like massage, deep breathing, or acupuncture.
- Avoid alcohol, cigarettes, and drugs. Self-medicating with alcohol or drugs may provide an easy escape from stress, but the relief is only temporary.
Prevention is the best intervention. By preventing and coping with stress more adequately, one can effectively modify cardiac risk factors and hence, strengthen the heart.