Optimism and the heart: what a meta-analysis of 230,000 people found

Does the way we see the future affect the health of the body? The question is old, but in recent decades researchers have begun to answer it with data from large studies that follow thousands of people for years.

The 2019 meta-analysis

In 2019 the American cardiologist Alan Rozanski and his colleagues combined the results of 15 studies with about 230,000 participants in total. Optimism had been measured with questionnaires at the start of the studies, and participants were followed for about 14 years on average.

Compared with less optimistic people, the most optimistic had about a 35 per cent lower risk of cardiovascular events, such as heart attack or stroke, and about a 14 per cent lower risk of death from any cause during the study period.

What the study does not say

These are observational studies. They show that optimism and health go together, but not necessarily that optimism causes better health. There may be other factors: people with more resources, less stress or better health from the start may also be more optimistic. The researchers tried to account for some of these factors, but not all of them.

Realistic optimism does not say "everything will be fine". It says "there are things I can do to make it go better".

How it might work

Researchers have proposed several explanations. Optimistic people tend to look after their health more: they move more, smoke less, follow medical advice better. They may also cope with stress differently, with more effort to solve the problem and less avoidance. And there is evidence, not yet conclusive, that chronic stress directly affects the cardiovascular system.

America's nurses

One of the largest sources of data on this subject is the American Nurses' Health Study, which has followed tens of thousands of women since the 1970s. In 2017 Eric Kim and colleagues analysed about 70,000 of them, who had completed an optimism questionnaire in 2004. Over the following eight years, the most optimistic women had a noticeably lower risk of dying from heart disease, stroke, cancer and respiratory infections compared with the least optimistic. The link remained even after the researchers took age, education, depression and existing illnesses into account, although it weakened partly when lifestyle habits were included.

Living to 85

In 2019 Lewina Lee and colleagues went a step further and asked whether optimism is linked to exceptional longevity, which they defined as surviving to the age of 85 or beyond. They used two large groups: the women of the nurses' study and the men of a study of American veterans. In both groups, the most optimistic people lived on average 11 to 15 per cent longer and were more likely to reach the age of 85. Here too the study is observational and does not prove that optimism causes longevity.

How optimism is measured

In most of these studies, optimism is measured with a short questionnaire called the Life Orientation Test – Revised, developed by Michael Scheier, Charles Carver and Michelle Bridges in 1994. It contains statements such as "In uncertain times, I usually expect the best" or "I hardly ever expect things to go my way", and the participant indicates how much they agree with each one. So optimism here does not mean always being cheerful, but having a general expectation that the future will hold more good than bad.

Defensive pessimism

Are pessimists always at a disadvantage? Not necessarily. The psychologists Julie Norem and Nancy Cantor described in 1986 a strategy they called defensive pessimism: some people deliberately lower their expectations before an exam or a speech and think in detail about everything that could go wrong. This channelled anxiety pushes them to prepare better, and they often do just as well as optimists. When they were asked to think positively instead, their performance actually got worse. There is no single right way to face the future, and each of us may need a different approach.

Can it be learned?

Optimism is partly inherited and shaped in childhood, but there are signs that it can be strengthened. One frequently studied exercise is the "best possible self", proposed by Laura King in 2001: for several days in a row, write for about 20 minutes about what your life would be like in the future if everything went well and you achieved your main goals. Later studies have found that this exercise temporarily increases positive expectations. The effects are modest and it is not known how long they last, but the exercise is easy, free and carries no risk.

Realistic optimism in practice

• Imagine your "best possible self". In some studies, writing for a few minutes about a future in which things have gone well temporarily increased optimism.
• Link hope with action. After every positive expectation, ask: what is my first step?
• Do not hide worry. Healthy optimism does not ignore symptoms or skip medical check-ups.
• Look after the basics: sleep, movement and relationships affect both mood and the heart.