FIR does seem to improve blood flow, improve wound healing time, and reduce inflammation. A study in mice showed increased capillary and micro-capillary growth with FIR treatment.
The one exercise recovery specific study
that I found did not report much of a recovery benefit with FIR. But if you happen to have a -100C (yes, minus 100C) whole body cryogenic chamber handy....
UA cites this paper
to support their claims.
From an Article in TIME
Michael Hamblin, principal investigator at the Wellman Center for Photomedicine at Massachusetts General Hospital, and an associate professor at Harvard Medical School, says that it’s reasonable to expect a garment emitting far infrared energy to help sleep. While no literature directly links far infrared exposure to sleep performance, anecdotal evidence, says Hamblin, supports Under Armour’s contention. The science has shown that far infrared energy does indeed improve long-term pain, help blood flow, and improve muscle recovery. “People who use far infrared can expect various benefits,” says Hamblin. “And better sleep is almost certainly one of them.”
I think I'll wait for the product reviews.