If you're young and you keep yourself physically fit by engaging in rigorous physical activities on a regular basis, that's one practice you will likely be grateful for when you get older.

You may already be reaping the rewards of exercising regularly as being physically active allows you to keep a healthy brain and body but a new study suggests that you can still reap the benefits of exercise in the future when you're already older as there's an apparent association between being physically fit in your 20's and being mentally fit when you reach middle age.

In the new study "Cardiorespiratory fitness and cognitive function in middle age" published in the journal Neurology April 2, researchers involved nearly 3,000 healthy participants who were between 18 to 30-years old to determine whether cardiovascular fitness has an impact on cognitive health 25 years later.

The participants were asked to run on the treadmill for as long as they can before they finally become exhausted to test their cardiovascular fitness. Twenty years later, the participants went through the same treadmill test only this time the average time has fallen from ten minutes to 2.9 minutes.

Twenty-five years after the first treadmill test, the participants underwent cognitive tests to measure their psychomotor speed, verbal memory and executive function. The researchers found that those who ran longer on the treadmill 25 years earlier performed better in the cognitive tests.

"This is one more important study that should remind young adults of the brain health benefits of cardio fitness activities such as running, swimming, biking or cardio fitness classes," said study researcher David Jacobs from the University of Minnesota, Minneapolis.

The researchers have likewise observed that those who lost less time between the first and the second treadmill tests tend to perform better on executive function tests.

Stuart Sealfon, from The Mount Sinai Hospital in New York City, however, said that while he finds the study interesting, it does not actually establish a cause and effect relationship between cardiorespiratory fitness in your youth to having better cognitive functions when you get older. He said that further study is still need to establish this causal relationship.