The Health Hypothesis

In a study of more than 900 women with an average age of 83, caregivers came out ahead on mental cognition tests. Those who were caregivers throughout the three-year period of the research had better cognitive function—defined in this study as verbal memory skills and mental processing speed—than women who had not been caregivers during the same period or those who had stopped caregiving during that time.

The participants, located in four areas of the U.S., were not selected based on caregiver status, but rather because they were part of a large sample of women age 65 and older, participating in a study of risk factors for osteoporotic fractures that allowed researchers to follow their health over many years. By 2009, they were "pretty representative of older healthy women across the country," says Lisa Fredman, a professor of epidemiology at Boston University School of Public Health who helped conduct the study on cognitive function.

Fredman's team set out to test a common assumption that stress among caregivers results in poorer health outcomes when compared with non-caregivers. They showed that "although caregivers may be more psychologically stressed than non-caregivers, they did not have negative cognitive consequences," Fredman says.

At their second annual follow-up interview, participants were given two cognitive measures: a word recall test and a digit symbol substitution exercise. All the women scored slightly below the norm for their age and gender on the word recall test, but the caregivers outperformed non-caregivers or previous caregivers on both cognitive tests. The caregivers, in fact, performed at the same level as participants 2 to 10 years younger, depending on the test.

Caregiving often keeps the caregiver busy and physically moving, Fredman explains. Even if stressful at times, it confers some benefit in that caregivers are doing something very important for someone who is meaningful to them. However, in a study such as this, it is possible that those who chose to be caregivers were more capable and qualified, and it may not necessarily mean that caregiving resulted in better scores.

"If you're firmly rooted in the stress theory, you assume that stress [leads to] worse outcomes, but we've been finding that there are variations to that theory for outcomes ranging from walking speed, to mortality, to cognitive functioning," Fredman says. She proposes instead a new hypothesis—a healthy caregiver hypothesis—that assumes the caregiving role, with its physical and mental demands, may also have health benefits.