They say you can’t teach an old dog new tricks, but a new study of adults aged over 65 suggests that raising fitness levels in later life can in fact boost brain function.

Researchers at the University of Kansas Medical Center (KUMC) led a six-month study of healthy adults aged 65+ with no signs of cognitive decline to determine the ideal amount of exercise necessary to achieve benefits to the brain. They found that virtually any increase in physical activity led to improved focus and attention, with more frequent exercise bringing greater benefits.

Trial participants were placed in a control group that did not have monitored exercise, or they were put into one of three other groups. One group moderately exercised for the recommended amount of 150 minutes per week, a second exercised for 75 minutes per week, and a third group exercised for 225 minutes per week.

All groups who exercised saw some benefit, and those who exercised more saw more benefits, particularly in improved visual-spatial processing – the ability to perceive where objects are in space and how far apart they are from each other. Participants who exercised also showed an increase in their overall attention levels and ability to focus.

"Basically, the more exercise you did, the more benefit to the brain you saw," said lead researcher Jeffrey Burns. "Any aerobic exercise was good, and more is better."

The research indicated that the intensity of the exercise appeared to matter more than the duration, backing up previous findings.

"For improved brain function, the results suggest that it's not enough just to exercise more," said Eric Vidoni, research associate professor of neurology at KUMC and a lead author of the study published in journal Plos One. "You have to do it in a way that bumps up your overall fitness level."

The results back up previous findings indicating that physical activity can help guard against dementia in later life. Meanwhile, research released this week found the dangers of inactivity in early life can have far-reaching repercussions. The findings presented at the Alzheimer’s Association International Conference 2015 showed young adults who shun exercise and spend large amounts of time in front of screens are twice as likely to have poor cognitive function in mid-life.