There’s no doubt that we’re living longer than previous generations. Now there’s encouraging news that those added years may be healthy ones as well. According to the latest tallies from the Centers for Disease Control and Prevention (CDC), in 2010 the average life expectancy rose from 78.6 years in 2009 to 78.7 in 2010. But the data has not been as definitive about whether that means people are stronger and healthier and therefore adding years to their lives, or whether medical innovations are extending lives, but leaving people sicker for longer.

Researchers from Harvard University report that there is some reason to be optimistic about our longevity. “Effectively, the period of time in which we’re in poor health is being compressed until just before the end of life. So where we used to see people who are very, very sick for the final six or seven years of their life, that’s now far less common. People are living to older ages and we are adding healthy years, not debilitated ones,” said David Cutler, the Otto Eckstein Professor of Applied Economics at Harvard University and author of the latest study, in a statement.

(MORE: Today’s 90 Year Olds Are Mentally Sharper Than Their Predecessors)

The research team looked at data gathered from 90,000 people between 1991 and 2009 who responded to the Medicare Current Beneficiary Survey (MCBS), an on-going evaluation of Medicare coverage and health outcomes. Unlike previous studies of morbidity among the elderly, which assessed people’s health at different ages and then compared this data to their death rates, the scientists in the current study started with the participants’ death, and then went a back each successive year to measure the subjects’ health at those points. That way, Cutler and his team were able to calculate at each health evaluation how far the individuals were from death, and document their health status at each of those times. To gauge how functional the participants were, the researchers studied data on whether the Medicare subscribers could cook, clean, or bathe themselves and manage their money.

The results showed that as a population, the elderly is remaining healthy into their later years. The findings do not determine what is behind this extended period of healthiness, but it’s possible that the same medical innovations that some feared were keeping us alive with more debilitating conditions may also be helping us to overcome common age-related chronic conditions such as heart disease and joint disorders, so they are not as challenging to treat as they once were.

(MORE: Brain Aging May Depend on Childhood Intelligence)

Other studies have found similar results. A Danish study earlier this month showed older people today are sharper than elderly folks in previous generations; comparing two groups of nonagenarians born a decade apart, the researchers found that those born more recently scored higher on cognitive function tests than those born earlier.

“All our studies suggest that we can change the rate of aging. When it comes to translating our findings, the question is are we going to delay everything or are we going to spend more time being sick,” says Dr. Nir Barzilai, the director of the Institute for Aging Research at the Albert Einstein College of Medicine, who studies the biology of aging and longevity but was not associated with the study. Barzilai is currently studying centenarians, and says that health care costs for those living to 100 can be third of those who don’t live past their 70s. Part of the cost savings, he says, comes from the fact that centenarians require fewer medical appointments and screenings.

More awareness of how to age well by eating a healthy diet, exercising and keeping the brain active are certainly helping more people to enjoy a higher quality of life into old age. But at a certain point, says Barzilai, genetics play a role. “Now when someone breaks their hip, in a few weeks you can get them to walk again. These guys were dying before. They were in bed, getting sores, getting pneumonia,” he says. The oldest old, however, likely have their genes to thank for seeing them past the chronic diseases that typically plague people past their 60s.

While encouraged by studies hinting that it’s possible to extend life in a healthy way, researchers are also concerned that the trend may be short-lived, thanks to obesity. With so many children in the U.S. suffering from obesity and adult diseases such as type 2 diabetes and high blood pressure, future generations may face a less healthy old age. Barzilai says there could be two groups elderly — those with obesity and diabetes who continue to suffer from health problems and require high-cost medical care into their golden years, and those without those conditions who are able to live relatively disease-free, long lives. “I am very aware of the epidemic of obesity and diabetes and its potential impact on lifetime,” says Barzilai. “Yes I am worried, yes it might be a challenge, but because we anticipate progress in [those areas] too, it might be okay.” If anything, the current generation of elderly should serve as a model for the healthy and robust life that’s possible for decades past middle-age.