Wednesday April 18 2012
Does happiness make us healthy or good health make us happy?
“Cheer up and save yourself a heart attack,” says the Daily Mail, which today reported that a positive outlook on life has been shown to keep your heart healthy.
It’s not clear if the Mail’s message is a positive or negative one, but before cheerier types out there rejoice at their good fortune or the gloomier among us feel destined for a heart attack, it’s worth examining the research behind the claim. The story is based on a review that systematically analysed research on whether positive psychological wellbeing and optimism are associated with cardiovascular health. Overall, the review suggests that feeling positive about life, rather than just a lack of pessimism, protects against cardiovascular diseases such as heart attack and stroke, and may also be associated with healthier behaviours such as not smoking or drinking too much, eating a better diet and sleeping well.
However, it is difficult to draw firm conclusions from this interesting research as psychological wellbeing is a complex area that is difficult to measure objectively. The authors of this new report acknowledge that many of the studies that they included had important limitations in their design and methods, making it impossible for the researchers to derive an accurate estimate of the potential relationship between positivity and heart health. Also, it is difficult to unpick the complex relationship between whether health improves happiness or if happiness makes you healthy.
Although the nature of any potential relationship between the two factors is still unclear, psychological wellbeing, just like heart health, is an important aspect of health. Anyone concerned about feelings of depression or their cardiovascular health should see their GP.
Where did the story come from?
The study was carried out by researchers from Harvard School of Public Health, US. There is no information about whether it received external funding.
The study was published in the Psychological Bulletin of the American Psychological Association. The review was reported uncritically in the Daily Mail, but the BBC stressed that the findings were not proof of a link between psychological wellbeing and a healthy heart. The BBC also included comments from an independent expert putting the uncertain nature of the results into context.
What kind of research was this?
This was a review examining the potential association between positive psychological wellbeing (PPWB) and cardiovascular disease (CVD). To examine the association, the researchers conducted a systematic review of all relevant existing research on the matter.
The authors say that while previous research has looked at the relationship between poor psychological functioning (such as anxiety and depression) and physical health, it is important to consider whether positive feelings of wellbeing (as opposed to just the absence of negative feelings) are associated with good health and, in particular, with cardiovascular disease.
The authors further distinguished between different types of wellbeing that have been examined in the wider literature. These are:
- “eudaimonic” wellbeing – defined as fulfilling one’s potential and identifying meaningful life pursuits
- “hedonic” wellbeing – which refers to the pursuit of pleasure and happiness
The researchers also looked at the quality of optimism, as well as other measures of wellbeing.
In addition, they looked at any association between PPWB and health behaviours such as smoking, alcohol consumption and physical activity, and at the relationship between PPWB and certain physiological factors relevant to heart health, such as atherosclerosis (fatty deposits in the arteries that are associated with cardiovascular disease).
Although the researchers performed a systematic review, they present their findings as a narrative review and did not perform a meta-analysis to combine the results quantatively. They say this is because of the diverse measures of PPWB and diverse outcomes measured by the individual studies.
What did the research involve?
The researchers reviewed studies examining an association between PPWB and cardiovascular health, as defined by objective indicators such as stroke and deaths due to cardiovascular disease. They say that they only included prospective studies that followed people over time (rather than examining their histories). They say prospective studies are the strongest possible way to test the theory that PPWB influences cardiovascular health. They looked at studies in both healthy and patient populations.
The authors also reviewed evidence on any association between PPWB and health behaviours such as smoking, alcohol consumption, diet and exercise. Finally, they looked at studies of the association between PPWB and relevant biological markers of CVD, such as hardening of the arteries (atherosclerosis), blood vessel function and the presence of proteins in the blood that indicate chronic inflammation (chronic inflammatory diseases are often associated with increased CVD risk).
The authors conducted literature searches in two electronic databases to identify relevant articles and based their selection of studies on a number of criteria. For example, they excluded studies where disease was only self-reported or where patients developed diseases other than CVD. However, the reviewers do not describe any methods for the assessment of the quality of included studies.
What were the basic results?
The authors present their results in an extensive narrative review and it is not possible to review the authors’ full discussion in detail here. In summary, the authors say that the evidence indicates that positive psychological wellbeing “protects consistently” against CVD, independent of other risk factors. The quality of optimism they say is most robustly associated with a reduced risk of cardiovascular events. Hedonic wellbeing (based on pleasure and enjoyment) has a stronger association with positive cardiovascular health than eudaimonic wellbeing (based on fulfilling one’s potential and wider social goals).
PPWB is also positively associated with “restorative” health behaviours and with biological function. For example, optimism is associated with better sleep quality, a healthy diet and physical exercise and, in terms of biological function, is associated with reduced risk of atherosclerosis. However, the authors say the findings in these two areas are less clear.
How did the researchers interpret the results?
The authors conclude that “PPWB is clearly associated with cardiovascular health, often over and above the effects of ill-being”. They say that continued investigation in this area is warranted since PPWB has critical implications for the onset and progression of cardiovascular disease, a finding that may provide new avenues for intervention and prevention.
This is an interesting review but, overall, it is difficult to draw firm conclusions from it on the potential relationship between psychological wellbeing and cardiovascular disease.
As the authors say, many of the studies used to compile their review had limitations in their design and methodology. Importantly, some of the studies included in the section on psychological wellbeing and health behaviours were cross-sectional, meaning they looked at individuals’ psychological wellbeing and health behaviour at a single point in time. This means they cannot show that healthy behaviour follows on from feelings of psychological wellbeing. Even in prospective studies, which follow people over a period of time to find out if wellbeing is related to the later development of CVD, it is possible that the person may have had early asymptomatic CVD at the time wellbeing was assessed, meaning their condition may have actually existed before their state of mind at the time had developed.
Another important problem with research in this area is that it can be difficult to isolate the effects of happiness and optimism from a whole range of interrelated factors that might also contribute to or be affected by heart health. For example, people who are more affluent may tend to be both generally healthier and happier, while people who are in good health may be happier as a result of being generally well. Although researchers often try to adjust their analyses to account for other factors that might influence a study’s results, it can be hard to do so accurately and important factors may not be taken into account at all.
Also, the studies included in the review used different methods for measuring psychological wellbeing and most of them relied on people self-reporting PPWB, which makes the results less reliable. Many people might also feel more inclined to describe themselves as optimistic by nature rather than gloomy, or might also change in mood relatively easily.
Psychological wellbeing is a complex area but is important to health for many reasons. Anyone concerned about feelings of depression or anxiety should see their GP.