Young, healthy elite boxers ≥ 18 years old are recruited. Prior to, and immediately after a competitive boxing bout over 3x2 or 3x3 minutes, blood samples are drawn. Boxers are randomized to intervention or control management by 1:1 allocation prior to baseline testing. After the initial post-fight blood sample is drawn and symptom rating using the sports concussion assessment tool-5 (SCAT-5) has been collected, the boxers receive either acute selective head-and-neck cooling for 45 min, or routine post-fight management. The number of head impacts are counted in all boxers on match video recordings. In both groups, blood samples are drawn 45 minutes after the initial post-bout blood sample, as well as 3 and 6 days post-fight.

Inclusion Criteria:

1. Male and female elite boxers ≥18 years old
2. Cleared for participation by the medical staff of the Swedish Boxing Association.
3. Informed consent by each participant prior to the competitive event
4. No boxing fights or match sparring during the initial 6 days after their last boxing fight
5. Signed informed consent.

Exclusion Criteria:

1. >40 years old or <18 years old
2. Participation in competitive fights, match-sparring or any training causing additional head impacts during the first six post-fight days after being included in the study.
3. History of autoimmune neurological diseases or a neurodegenerative disorder.
4. History of previous traumatic brain injury resulting in an intracranial haemorrhage.