“Work as long as you can and volunteer if you can’t work,” says Dr. Yoram Maaravi, who leads the ongoing study on aging.The secret of the fountain of youth has always been an elusive goal: as we grow older, how does one maintain energy, physical and mental performance – and most importantly, how does one extend their lifespan as long as possible?

A 13-year study of senior citizens by the Department of Rehabilitation and Geriatrics, Hadassah Hospital Mt. Scopus at Hadassah Hospital has shown conclusively that one of the clearest answers is both simple and inexpensive: keep working.

“You want to live longer? Work as long as you can and volunteer if you can’t work,” says Dr. Yoram Maaravi, who leads the ongoing study.

The study – involving 1000 senior citizens all born in 1920 – found that working or volunteering significantly increases the chance of functioning to an older age. Those who continued working past the age of 70, in either a paid or volunteer position, have a much higher chance of still being alive – and functioning independently – at age 77 and beyond.

It made little difference, the study found, if the work or volunteer activity was took place every day or once a week, and there was no link found between the type of work and the physical effort it required. Even work that did not require physical effort was beneficial.

According to Maaravi – the acting director of the Geriatrics and Rehabilitation Department at Hadassah University Hospital – the benefits of working have nothing to do with bringing home a paycheck – volunteer work has the same beneficial effects as paid employment.

“Working had a tremendous effect, we can’t answer the question yet if the reasons are physical or mental, but it’s clear that it has a lot to do with personal satisfaction, enjoying yourself and socialization,” he said.

As important as keeping busy is to keep moving. “A factor that affected the life expectancy dramatically was moderate physical activity, the kind that is easy to adapt in old age: as easy as walking an hour per day. In our study there was a mortality rate of 23 percent of non-walkers and only 3 percent of the walkers,” Maaravi said. “That is six times lower mortality. One wonders how many billions of dollars the pharmaceutical industry would pour into a drug that could lower mortality that significantly.”

The Hadassah study is unique in that it is one of the only such studies which gathered such a large group of people who are precisely the same age. The group of 70-year-olds gathered 13 years ago were reflective of the population makeup of Jerusalem. Both in the beginning of the study and at regular intervals, the subjects have undergone medical examinations, filled out detailed questionnaires regarding their daily habits, and have been visited at home.

The study has collected information at seven year intervals – including data on the person’s social and economic status, functioning, habits, work and leisure activities, relationship with family, and comprehensive health information that includes a physical exam and lab test including DNA samples.

The information culled has been rich and valuable, says Maaravi. “Every day, when we look at our data, we are surprised by something and learn something new.”

Its findings regarding the lifespan benefits of physical activity have never been proven so conclusively in the past, according to Maaravi. A 60% lower mortality rate was found in the 70 year olds who practiced some sort of physical activity than those who didn’t.

In addition, warned Maaravi – only half-joking – “An afternoon nap can be dangerous.”

Surprisingly, a higher rate of mortality was found among those participants who napped in the afternoon on a regular basis – twice as high as those who usually don’t nap. The researchers theorized that a possible explanation for this is an increase in the pulse rate and stress on the heart that takes place after awakening.

Other findings included the fact that decrease in sight at age 70 predicted a higher rate of dependence in physical and mental performance as well as a higher mortality rate at age 70. In addition, a slight decrease in kidney function (undetectable in regular blood tests) and common in this age group (found in 50% of the participants) predicts a higher mortality rate.

These conclusions are valuable for the identification of elderly at risk – by following the guidelines of the study, geriatric doctors can learn to encourage paid and volunteer work for their patients, and screen their patients for decreases in sight and kidney function in order to detect and treat these conditions as early as possible.