The idea that there is a threshold of 1100 below which heading is safe is implausible to me. If heading is unsafe, more heading has a larger chance of causing injury, and there is nothing magical about the number 1100. I doubt that IQ can be raised, but people should try to avoid doing things that lower it. There has been much attention recently about brain damage caused by concussions in (American) football, and the NYT just had an article about brain damage in hockey players and boxers
I'll have my kids play sports that do not involve blows to head.
Along the lines of "
Is it okay below the cutoff level?"...
I've been reading about lead poisoning and the amount of blood lead that causes brain damage. I learned something very interesting. In 2003, a group of researchers tested the IQs of children with high and low levels of blood lead.
High was defined as any measurement that was above the CDC's cutoff for elevated blood lead (10 ug per dL). As expected, the researchers found that IQ dropped as blood lead increased: each increase of 10 ug/dL was associated with a loss of 4.6 IQ points. This result was consistent with results of other studies.
They also decided to check cognitive function in children with
low blood lead. So they measured IQ in kids whose blood lead had been in the 1-10 ug/dL category all their lives.
What was really surprising was that IQ dropped
7.6 points in this group --- in other words, more damage happened in the category
below the CDC's cutoff for elevated blood lead. This group did a larger study that was published in 2007 and got similar results. There are summaries of the two studies
here and
here. PM me if you want the papers.
So, do I know if 1,016 annual head blows from a soccer ball are safe and 1,154 would be dangerous? No. But the lead study makes me wonder. And given what we know about head injuries, it's reasonable to assume that pounding your head frequently (or semi-frequently) with a soccer ball moving at high speed probably isn't super-good for your brain.
