Opportunities in dynamic Chinese stocks markets continue to attract large numbers of investors. Share prices in China are volatile, with substantial opportunity and risk. In 2015, after considerable growth in value, prices have plummeted in the past several weeks. Foreign investment in Chinese stocks is restricted; sophisticated international institutional investors typically purchase so-called 'H shares' in the Hong Kong market. On the other hand, so-called 'A shares' in mainland Chinese companies have been largely restricted to local investors on the domestic Shanghai and Shenzhen stock markets. These home markets are dominated by relatively inexperienced, small investors with high expectations for potential returns and less appreciation for the unpredictable and fickle nature of stock markets. Crises in stock markets generate dramatic headlines, emphasizing risk of financial or economic collapse; however, little attention is paid to the potential effects on the physical health of distressed investors.
Mental stress can precipitate heart attacks and sudden cardiac death, especially in people with coronary artery disease. In 2011, Chinese epidemiologists reported that rapid declines in the Shanghai Stock Exchange Composite Index were associated with increased death rates from coronary artery disease. Remarkably, deaths also occurred when the Index rose rapidly. The fewest cardiac deaths occurred when the Index was stable; each 100-point change in the Index (up or down) was associated with about a 5% increased death rate. In the United States, a study based on the Duke Databank for Cardiovascular Disease in North Carolina found an increased rate of heart attacks during the stock market crash in 2008-2009. However, an epidemiological study conducted in Los Angeles County in California found that death rates did not increase there during this crash.
Other types of stress increase cardiac deaths. A major earthquake can increase heart attacks as well as sudden death in subsequent days. In 1991, hospital admissions for heart attacks increased in Israel during the Iraqi missile attacks in the first week of the Gulf War. Major sporting events can have the same effect; several careful studies have demonstrated an upsurge in heart attacks in supporters of teams competing in pivotal matches in the men's soccer World Cup.
While these observational studies in large populations demonstrate that powerful mental stress can often be associated with heart attack and death, the fact that one event is followed by another does not necessarily mean that they are linked by a cause-and-effect relationship, in as much as the pre-dawn delivery of the daily newspaper does not cause the sun to rise. However, careful experimental studies have repeatedly demonstrated that even mild mental stress in people with coronary artery disease can deprive the heart of needed oxygen. The brain can initiate physiological responses that can damage the heart, primarily by activating the sympathetic nervous system to release noradrenaline (norepinephrine) in the heart, and by causing the adrenal glands to secrete adrenaline (epinephrine) into the blood. Adrenaline stimulates the heart to beat faster and harder which increases the heart's need for oxygen. Adrenaline and noradrenaline may also increase the risk of rupture of plaques in atherosclerotic coronary arteries and increase the likelihood that clots may block diseased arteries. These and other mechanisms support the widely held view that emotional stress can have sudden, unpredictable and major cardiovascular consequences.
We can only speculate about the extent of cardiovascular adversity precipitated by the current financial crisis in Greece, and potentially also in Puerto Rico going forward. Along with a healthy diet and life-style, keeping emotions out of investment decisions might be a wise move. According to many academic studies and thoughtful investment analysts, adhering to a sound personalized financial plan--reviewed perhaps annually--with appropriate asset allocation using diversified, inexpensive index funds is a prudent and effective strategy for good financial returns in the long run. While always challenging to maintain thoughtful behavior and masterful inactivity during inevitable crises, sticking to such a largely passive investment plan might also keep your heart in better shape too.