Jazz singer Louis Prima knew a thing or two when he crooned, "Enjoy yourself – it's later than you think."
As it turns out, older adults with joie de vivre maintain better physical function and keep up faster walking speeds as they age, compared to contemporaries with less zest for life, according to a study published Monday in the Canadian Medical Association Journal.
For the study, researchers from University College London recruited 3,200 adults aged 60 and up, and followed them for eight years.
They discovered that participants with a lower enjoyment of everyday life had an 80-per-cent increase in odds of developing two or more impairments interfering with everyday activities, such as getting dressed. The increased risk was "striking" compared to the odds for adults who enjoyed life, the researchers wrote.
They did not find, however, that happier adults were more likely to exercise, resulting in better physical condition, noted lead author Dr. Andrew Steptoe, an epidemiologist at University College London.
"When we took account of exercise habits, this did not make much difference to the association between enjoyment of life and [better] physical function," he wrote in an e-mail.
Rather, Steptoe and co-authors theorized that a positive mental state may reinforce biological processes that promote good health.
In a 2010 study, Steptoe and colleagues cited research showing that a positive mood had beneficial effects on heart rate, blood pressure and levels of the stress hormone cortisol. These biological processes may be partly responsible for the protective effects of positive mood on health outcomes, they concluded in the report, published in the journal Neuroscience and Biobehavioral Reviews.
In their newest study, Steptoe's team divided participants into three age categories: 60 to 69, 70 to 79 and 80 years or over. They assessed participants' enjoyment of life based on their answers to these statements: "I enjoy the things that I do," "I enjoy being in the company of others," "On balance, I look back on my life with a sense of happiness" and "I feel full of energy these days."
The researchers used personal interviews to determine whether participants had difficulties getting out of bed, getting dressed, bathing or showering. They gauged walking speed with a gait test.
They found that younger participants – those aged 60 to 69 years – had higher levels of well-being, as did those with higher education and socioeconomic status, and those who were married and working.
Even when the researchers accounted for low socioeconomic status and chronic illnesses such as heart disease and depression, they found that people with low well-being were more than three times as likely as their positive counterparts to develop problems in their daily physical activities.
After adjusting in their statistical analysis for factors that might contribute to low well-being, Steptoe said, "We still show links between positive well-being and reduced risk of impairments in activities of daily living."
Cultivating enjoyment of life may be a good defence against age-related decline, while efforts to enhance well-being "may have benefits to society and health-care systems," the study authors wrote.
There is no easy prescription for a positive mental attitude, Steptoe acknowledged. However, regular exercise and "contact with family and friends as well as the wider world" may contribute to well-being, he added.
And, of course, it's never too late to see the glass as half-full.