A new study into low-impact brain injuries published by the journal Neurology looked into the accumulated effects of non-concussion blows over the course of a single season, and the results are unsettling.

The study followed athletes at Dartmouth College, observing both a group from contact sports and a group from noncontact sports. The athletes received cognitive functioning tests and brain scans pre-season and wore helmets that calculated the intensity of blows to their heads during the season. Then, they underwent the same cognitive functioning tests and brain scans post-season, and the differences between the two groups was quite revealing.

Before the seasons started, testing revealed few differences between the athletes who played contact sports and those who played noncontact sports. But post-season, the differences in the strength and frequency of hits to the head the two groups had sustained, even the non-concussive ones, were reflected in distinct brain imaging differences. Those who were being hit in the head more often, even if the blows were not concussive, were performing worse.

According to the Fox News article, “20 percent of the contact players scored more than 1.5 standard deviations below the predicted score on tests of verbal learning and memory at the end of the season, compared to 11 percent of the non-contact athletes.”

What we’re unsure of is how long-term these effects are; further study is needed. It could be that in the offseason, the brain mostly heals and bounces back, as it were, to its normal functionality. Remember, there were few differences between the two groups at the beginning of the season. And, since they were playing at the college level, it’s probably safe to assume the athletes had played many seasons prior to the one in the study. So whatever damage previous seasons had inflicted, the brain had recovered at least somewhat.

But if recent research as proved anything, it’s that repetitive hits to the head are never a good thing in the long run. And this study proves that even lesser hits that don’t result in a concussion diagnosis are harmful to athletes’ brains over time.

So remember that everything you do to protect an athlete in a contact sport helps. Because head blows are harmful, no matter how small.

*Scientists have no conclusive evidence as to whether or how the reduction of g-forces during impacts reduces the number or degree of concussions and head injuries. GelDefenderTM products provide supplemental padding as well as cooling and comfort benefits when used with helmets and caps. Participants in activities in which head impacts can occur should always use tested and approved helmets for protection. However, no helmet or supplemental padding can protect the user from all serious head or neck injuries that can result from impacts.