Staying fit is one of the best ways to lower the risk of dementia — even for those with a genetic predisposition to the condition.

A new study in the British Journal of Sports Medicine calculated a 35% decrease in the odds of developing dementia among those with a genetic risk but who have a high level of cardiorespiratory fitness, or CRF. CRF refers to how well the heart, lungs, and muscles work together to supply oxygen during sustained physical activity. It’s a measure of overall cardiovascular and respiratory efficiency and is often assessed through activities like running, cycling, or brisk walking. In general, higher cardiorespiratory fitness is linked to better heart health, lower disease risk, and improved endurance.

Overall, high CRF cut the risk by 40%, according to the new evidence. The researchers discovered that CRF was related to dementia risk in a linear, “dose-dependent” manner. The higher fitness that a person had at baseline, the lower their risk of developing dementia. This confirms years of previous research linking a lack of fitness with a higher risk of dementia. But the finding that people at genetic risk can lower that risk if they’re fit is a new piece of evidence, according to Kerem Shuval, PhD, MPH, a research professor at the Texas Tech Health Sciences Center in Lubbock, Texas, who was not involved in the new study.

Lead study author Qing Zeng, PhD, said the research “strongly suggests that physical exercise is an important component of comprehensive prevention strategies against dementia.” Zeng is professor of clinical research and leadership at George Washington University’s medical school in Washington, D.C.

Dementia causes problems with thinking, memory, and reasoning. The new study analyzed data from more than 61,000 British people over 12 years, ranging in age from 37 to 70 at the start of the study. Their fitness was gauged by a 6-minute test on an exercise bike. CRF refers to how well the body delivers oxygen to muscles. People in the new study also had their genetic risk for Alzheimer’s disease assessed when they enrolled in the UK Biobank program. Neuropsychological tests assessed their cognitive function. Higher CRF was associated with higher cognitive function at baseline. The study was observational and didn’t address cause and effect.