This blood flow restricting collar is interesting. I can’t claim to fully understand its side effects. Probably others more knowledgeable, such as @RAyers, can remove my ignorance. Everyone, correct me when I go wrong here!
As I understand it, the device works by restricting blood flow to thus build up a larger amount of blood in the brain. This serves to prevent brain “sloshing” upon an impact to the skull. This then prevents micro-damage to the brain structures.
It also seems inevitable that internal brain blood pressure is increased as a result of the restricted flow in the veins. There are studies (2003, British Journal of Ophthalmology) which show restrictions around the neck (such as tight neck ties) produce increases in intraocular pressure which isn’t good for eye health and other risk factors.
It also seems that brain cooling, via blood flow, would be inhibited somewhat by the restrictions. It’s well known that this cooling is required for proper brain function, mental acuity, and cellular health.
I am assuming that the user will wear the device all the time, or at least all the time they wear a riding helmet. They may likely have it on when the helmet is off. It could be worn for hours during a day. So, the usage model is not sporadic or intermittent use, or only when competing. The trials / studies were not of long term use. They had subjects wear them during their sport competition and then remove them. And a few subjects stopped wearing them. No one wore them most of the day. The research study, which was quoted, mentions that more work is required to understand the long term use for sport with increased brain blood volume. The animal studies (rats and pigs) are unclear how long they wore the devices.
There are some constraints and recommendations (fitment, other medical conditions, etc) which users will want to consider. It’s like one doesn’t want a loosely fitting helmet and expect that it will actually help in a fall.
Note that I am not against this novel device at all. To the contrary, I think it’s quite fascinating. I’m just looking to become more educated on the subtle aspects of how it works.
Have a great ride everyone!