Michigan State University researchers have found a link between memory and fitness that highlights yet another reason why we should all try and build some sort of physical activity into our daily routines.

A number of high-profile studies have already demonstrated how a lack of exercise leads to an increased risk of a host of illnesses, including coronary heart disease, type 2 diabetes, and breast and colon cancers. And now it would appear that sitting still for too long is also adversely affecting our memories.

In a small-scale, qualitative study of 75 college students over a two-day period, researchers found that those with the lowest fitness levels struggled the most to retain information.

Participants were asked to study word pairs -- two words that have an association, such as "camp" and "trail" -- then the following day were tested to see what they had and hadn't managed to commit to their long-term memory.

Long-term memory is defined as recall of anything learned more than 30 seconds previously and the findings are potentially worrying. Fitter students remembered more.

"The findings show that lower-fit individuals lose more memory across time," said Kimberly Fenn, study co-author and assistant professor of psychology.

Although a small-scale study, the findings are important because this marks the first time that young, supposedly healthy people have been tested in this way: research already exists on how exercise improves children's and the elderly's ability to remember.

The students' aerobic fitness levels were measured via treadmill tests (to understand how oxygen is consumed in the body) and by factoring in weight, body fat levels, age and sex. And in doing so the researchers noted their surprise at the low fitness levels of the participants involved.

Experts recommend that adults partake in a minimum of 150 minutes of moderate aerobic physical activity a week -- whether it be walking, jogging, cycling or swimming -- in order to protect themselves from the health risks of a sedentary lifestyle.