Part II
Impact of Humor and Laughter on Specific Disease Conditions
As noted earlier, while the first phase of research focused on general health-promoting mechanisms associated with humor, a second wave of studies began to study the impact of humor on specific disease conditions. These studies began right at the turn of the new century and continue to expand today.
Coronary Heart Disease
Coronary heart disease is the number one cause of death in the United States (for women and men), as well as in most other industrialized nations; it is responsible for about one in five deaths.88 In 2009, well over one and a quarter million Americans were expected to experience a new or recurrent coronary event. We have long known about such risk factors as poor diet, lack of exercise, smoking, and family history, but the fact that these factors only account for half the incidents of CHD89 has led researchers to cast their net much more widely in recent years to find additional things that start some individuals down the path toward CHD. One of these additional risk factors is your habitual daily emotional state. We now know that learning to better manage your emotions, assuring that you do not wallow in negativity (depression, anxiety or anger) is crucial (along with doing the right thing in terms of diet, exercise, smoking, etc.) to maximizing your chances of sustaining a healthy heart well into your senior years.
Temporary increases in heart rate and blood pressure do not pose a health risk. This is a normal and natural response to any stress or perceived threat. It is part of the classic "fight or flight" response. The risk to health comes when this condition is present day after day over a prolonged period of time.90 This risk is greatest for coronary heart disease and stroke.91 There is exciting new evidence, however, that humor and laughter can support good cardiac health - both for individuals who have already suffered a heart attack and those who have not. Since this research specifically focusing on the cardiac benefits offered by humor is just starting, we'll first take a brief look at the broader field of research on the impact of negative and other forms of positive emotion (excluding humor) on heart health. This will help put the heart-healing benefits of humor in better perspective.
Impact of Negative Emotion
A very large body of research now shows that persistent negative emotions and thoughts contribute to both the onset and progression of CHD.92 Chronic anger, especially, has been closely linked to heart disease for many years. Individuals with the classic "Type A" personality have long been considered to be on the fast track to a heart attack. These are people who are competitive, have a sense of time-urgency and can't relax, and generally carry around a lot of anger and hostility.93 These qualities sharply increase the risk of CHD, independent of one's age, systolic blood pressure, smoking and cholesterol level.94 Among men who have already had a myocardial infarction, Type A men are also more likely than Type B men to have additional subsequent heart attacks.95 This elevated hostility even shows up as greater enjoyment of hostile than non-hostile humor.96 Chronic depression, anxiety, a sense of hopelessness and the bottling up or suppression of one's emotions have also been shown to be risk factors.97
In the case of chronic hostility and anger, the problem is that these emotions generate frequent and prolonged elevation in both heart rate and blood pressure (generally referred to as increased "cardiovascular reactivity"), which progressively takes you down the path toward later hypertension and atherosclerosis.98 Even among persons who do not have coronary heart disease, their current level of hostility predicts the subsequent severity and progression of atherosclerosis.99
A single episode of extreme anger or stress is sometimes sufficient to trigger a heart attack. In fact, the likelihood of a heart attack has been shown to be twice as great in the two hours following an episode of anger.100 Research suggests that about 30% of the "attributable risk of acute myocardial infarction" can be accounted for by stress. "Psychosocial stress appears to adversely affect autonomic and hormonal homeostasis, resulting in metabolic abnormalities, insulin resistance, and endothelial dysfunction."101 (Italics are McGhee's.)
Sharply elevated stress in an entire community can similarly boost the incidence of heart attacks. In the 1991 war with Iraq (Operation Desert Storm, in which Iraq initiated attacks on Israel), death rates from heart attacks in Israeli cities targeted by Scud missiles were twice what they would normally be.102 Similarly, on the day of the Los Angeles earthquake in 1994, deaths from sudden heart attacks were five times what would normally be expected for the day.103 Depression, anxiety and hopelessness have also been shown to increase the risk of both the development and progression of CHD.104 Other evidence similarly shows that depressed mood (depression and emotional distress) predicts mortality among patients with congestive heart failure.105
• Damage to the Inner Lining of Arteries Resulting from Negative Emotion Starts You Down the Path to CHD. The integrity of the endothelium or inner lining of artery walls has long been known to be crucial to good heart health. The progressive build-up of plaque (containing cholesterol and lipids) in artery walls is called atherosclerosis, and it generates the path that sets you up for CHD as the years go by. As this process continues, it becomes increasingly difficult for the walls of blood vessels to expand and contract normally. This progressively reduced capacity for expansion and contraction, combined with the plaque-induced reduction in the inner diameter of the vessels, leads to high blood pressure and sharply increased risk of CHD.
A healthy endothelium is able to effectively expand and contract to meet the demands placed on the body at any given moment. But, as arteriosclerosis proceeds, arteries become stiff and lose their capacity to expand and contract as needed. The extent of loss (dysfunction) of this expansion/contraction capacity of coronary arteries has been shown to be directly related to the extent and severity of coronary artery disease,106 and is an independent predictor of cardiovascular "events" (including heart attacks, unstable angina and other coronary difficulties).107
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While we have long known about the role of diet in determining how far one goes down this path, there is growing evidence that your daily emotional state makes a contribution, as well. The key issue here is whether one's (negative or positive) emotional state can influence the endothelium's ability to expand or contract in a normal or healthy fashion. In the case of negative emotion, there is evidence that both short-term and habitual negative emotion interfere with this process. For example, when healthy middle-aged men were exposed to a stress-inducing circumstance in which they had to defend themselves against a charge of theft, the capacity of the inner wall of arteries in the arm to dilate (in response to use of a blood pressure cuff) was reduced (in comparison to a baseline of artery dilation capacity established prior to the stressor) both 30 and 90 minutes after the stressor.108 While the mechanism for this effect is not clear at this point, it shows that the negative emotion accompanying a specific stressful experience does reduce the capacity of arteries to expand and contract in a healthy or normal fashion.
Other research has shown that personality measures which assess one's habitual proneness to negative emotion similarly predict reduced capacity for vasodilation. For example, women found to show high levels of anger (and Type A behavior), anxiety or depression during their middle adult years showed significantly lower capacity for dilation of an arm artery (using the same procedure described in the previous paragraph) 13 years later.109 There is also some evidence suggesting that that depression may play an even more important role than anxiety in the development of vasodilation dysfunction.110 (As noted above, this kind of dysfunction of the endothelium is an accepted early marker of atherosclerosis and cardiovascular disease).111
It would appear, then, that learning to manage one's emotions more effectively can be added to the classic dietary advice (reducing intake of bad forms of cholesterol, fats and oils) when it comes to minimizing one's risk of heart disease. Humor and Nursing II discusses the evidence showing that humor is an effective tool for substituting a positive for a negative emotional state.
Impact of Positive Emotion (excluding humor)
With the recent explosion of interest in positive emotion in general (as part of the new field of psychoneuroimmunology), evidence is quickly accumulating to make the case that any source of habitual positive emotion may contribute to good cardiac health. Humor is simply the most fun way to use positive emotion to help maintain heart health.
There are two key questions to answer here in connection with cardiac health. First, does positive emotion help prevent CHD or heart attacks? Second, can it help promote recovery among individuals already suffering from CHD? We will shortly ask the same questions in connection with humor.
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• Preventing Heart Disease. Different forms of positive emotion have been shown to be associated with reduced risk of heart disease or heart attacks. Optimism, of course, is one source of habitual positive emotion. An optimist is a person who has a general disposition to be positive about future outcomes.112 This does not mean that s/he is always positive or never experiences negative emotion or doubt. S/he simply has a chronic tendency to see the bright side and expect a good outcome in life. In a study of older male war veterans, optimists were less than half as likely as pessimists to suffer from angina or heart attacks over a 10-year follow-up period.113
• Facilitating Recovery from Heart Disease. Optimists have been shown to have faster recovery than pessimists following coronary artery bypass surgery - both immediately after the surgery and six months later.114 They are also less likely to be rehospitalized (for either cardiac or any other issues) following their surgery.115 Consistent with these findings, among a group of elderly patients hospitalized with cardiovascular disease, those who reported greater levels of happiness over a 90-day period following their release from the hospital had lower readmission rates to the hospital than individuals with lower happiness levels.116 In fact, the self-reported positive emotions of these patients during this period predicted their (lower) readmission rates even when their length of initial hospital stay and health status at initial release were taken into consideration.
