Experts say that a lack of physical activity leads to age-related weakness and poor health in older adults. Official guidelines suggest that healthy older adults spend at least 2.5 hours every week doing moderate activity (such as brisk walking), or at least 1.25 hours per week doing vigorous exercise (such as jogging or running).

Unfortunately, many older adults are not physically able to perform either moderate or vigorous intensity exercise. Researchers created a study to learn more about how much exercise older adults are able to perform, and how that exercise affects their health.

The research team studied 6,489 female participants aged 63 to 99 years old. The researchers published their findings in the Journal of the American Geriatrics Society.

The participants agreed to take in-home exams, answer health questionnaires, and wear accelerometers (devices similar to fitness trackers). The participants also kept sleep logs.

The study was conducted between 2012 and 2013. The researchers reviewed death certificates as of September 2016 to learn how many participants had died.

At the beginning of the study, most participants were in their late 70s and most were considered overweight according to BMI standards (a ratio comparing height to weight). Nearly 30 percent were considered obese.

Most participants scored 8.2 out of a possible 12 points on physical function assessments. Based on accelerometer measurements of the participants:

1 percent performed "low" light-intensity physical activity

29 percent performed "high" light-intensity physical activity

15 percent performed moderate to vigorous physical activity

After examining the deaths in the women according to their activity levels, the researchers learned that older women with higher levels of physical activity were less likely to die than women with lower levels of physical activity, no matter the cause of death.

The researchers concluded that their findings support encouraging older women to increase the amount of time they spend every day in light-intensity activity, and reduce the amount of time spent sitting.