New York, Aug 13 (IANS): If you want your kids to shine in maths, allow them play time as researchers have found that fitness enhances math skills by aiding the development of brain structures that contribute to mathematics achievement.

Children who are aerobically fit tend to have significantly thinner gray matter - the outermost layer of brain cells in the cerebrum -- associated with better mathematics performance, the findings showed.

"Gray matter thinning is the sculpting of a fully formed, healthy brain. The theory is that the brain is pruning away unnecessary connections and strengthening useful connections," said lead researcher Laura Chaddock-Heyman from the University of Illinois in the US.

Previous studies have shown that gray matter thinning is associated with better reasoning and thinking skills, Chaddock-Heyman said.

"We show, for the first time, that aerobic fitness may play a role in this cortical thinning," she pointed out.

The analysis included 48 nine and 10-year-old children, all of whom had completed a maximal oxygen uptake fitness test on a treadmill.

Half of the children (the higher fit kids) were at or above the 70th percentile for aerobic fitness, and half (the lower fit kids) were at or below the 30th percentile.

The researchers imaged the children's brains using MRI and tested their math, reading and spelling skills.

The team found differences in math skills and cortical brain structure between the higher fit and lower fit children.

In particular, thinner gray matter corresponded to better math performance in the higher fit kids.

No significant fitness associated differences in reading or spelling aptitude were detected.

The study was published in the journal PLOS ONE.