People over 65 who strength train frequently die less often than those who don't. But they do have to hit the gym or their own torture chamber, where their old iron dumbbells and elastic bands lie scattered about, at least twice a week.

Study
In 2016, researchers from Penn State College of Medicine published an epidemiological study in Preventive Medicine in which they analyzed data from approximately thirty thousand people over the age of 65. The study participants had participated in the National Health Interview Survey, a health survey in the United States.

The researchers were able to follow the participants for up to fifteen years. During that period, 32 percent of them died. The researchers then determined whether strength training could reduce the risk of death.

In the Physical Activity Guidelines for Americans, the US government advises adults and older adults to participate in some form of strength training at least twice a week. [odphp.health.gov.] Based on this, the researchers divided the study participants into two groups - one group that met the guidelines and one group that did not.

Results
One in every ten study participants met the guideline. Specifically, 9.6 percent of study participants met the guideline. Those in this group had a whopping 45 percent lower risk of death than those who did not meet the guideline.

Click on the table below for a larger version.

The major problem with such associations is that they don't tell you much. Does strength training improve health and therefore reduce the risk of death? Or do healthy people do strength training more often than unhealthy people? And do people who strength train therefore die less often?

The researchers tried to rule out the second explanation as much as possible by eliminating confounding factors with statistical tricks. They did this for age, sex, race, ethnicity, education level, marital status, BMI, smoking, alcohol consumption, aerobic physical activity, and chronic conditions such as hypertension, diabetes, cardiovascular disease, and cancer.

When the researchers had neutralized these factors to the best of their ability, people over 65 who trained with weights at least twice a week still died 18 percent less often than people over 65 who did not meet the standard.

Conclusion
"This study further demonstrates the importance of encouraging doctors to recommend physical activity to patients as they would any other effective treatment, particularly since exercise has been shown to be as effective as some medications", the researchers write.

"Identifying interventions to successfully engage older adults in guideline-concordant strength training has the potential to significantly reduce all-cause mortality in this population."