Increased life satisfaction may stem from greater physical and psychological well-being, not just physical, according to a new study published in The Lancet.

The existing premise is that life satisfaction decreases in middle age before rising in older age, but researchers from Princeton University, Stony Brook University, and University College London found this idea is limited to high-income, English-speaking countries. "What is interesting is that this pattern [of decreased life satisfaction] is not universal," Angus Deaton, study co-author of Princeton’s Woodrow Wilson School of Public and International Affairs, said in a press release. "Other regions, like the former Soviet Union, have been affected by the collapse of communism and other systems. Such events have affected the elderly who have lost a system that, however imperfect, gave meaning to their lives, and, in some cases, their pensions and health care."

Deaton and his fellow researchers analyzed previous data collected by Gallup World Poll and the English Longitudinal Study of Ageing, measuring for evaluation well-being (elevations of satisfaction), hedonic well-being (feelings or moods of happiness and anger), and eudemonic well-being (judgment about the meaning of life). And tallying the life satisfaction scores across different countries, researchers found a “U-shaped curve that bottoms out between the ages of 45 and 54 in high-income, English-speaking countries,” while this curve doesn’t exist outside these countries, which include the United States, Canada, the United Kingdom, Ireland, Australia, and New Zealand.

In Eastern European countries and the former Soviet Union, there’s a steady and sharp decline in life satisfaction as people age. This could have to do with hedonic well-being. Middle- and older-age populations in countries with a curve experienced less worry, stress, and pain, compared to spikes in worry, stress, and unhappiness in countries with no curve. With eudemonic well-being, researchers compared a population’s purpose of life to survival rates among the elderly, finding elderly rates increase when they feel they have a purpose. "Even though the results do not unequivocally show that eudemonic well-being is causally linked with mortality, the findings do raise intriguing possibilities about positive well-being being implicated in reduced risk to health," researchers wrote.

Researchers also added for as much as they’ve discovered a focus on physical and psychological well-being can increase health and happiness, more research is required to deepen this understanding and possibly curate a plan to better address this balance. In the meantime, keep that scheduled spin class and don't forget to give yourself a break time and again.

Source: Subjective wellbeing, health, and ageing. The Lancet. 2014