Exercise-Induced Collapse (EIC) in Labrador Retrievers: What Breeders Need to Know

Exercise-Induced Collapse (EIC) is an autosomal recessive condition affecting Labrador Retrievers (and some related breeds) that causes affected dogs to develop progressive weakness and collapse after 5–20 minutes of intense exercise. It is caused by a mutation in the DNM1 gene and is testable by DNA before clinical signs appear.

What Happens During an EIC Episode?

Affected dogs (EIC/EIC) appear normal at rest and during moderate exercise. After 5–15 minutes of highly intense exercise — typically retrieving, hunting, or competitive field work — they begin to show hind limb weakness that progresses to a rocking, drunken gait. In severe episodes, the dog collapses and is unable to continue. Body temperature is often markedly elevated.

Most dogs recover within 5–30 minutes of rest, though a small percentage have died during episodes.

Who Is Affected?

EIC is an autosomal recessive condition — meaning both copies of the DNM1 gene must carry the mutation for the dog to be affected. Dogs with one copy (carriers) show no signs of EIC under normal circumstances.

EIC primarily affects working and field-trial Labradors, where the intense, repetitive exercise required by field competition brings on episodes. It is considerably more prevalent in field-line Labs than in show lines, reflecting the breeding history and the type of exercise each population experiences.

DNA Test Results

EIC Clear (N/N): Two normal copies of DNM1. The dog will not develop EIC and cannot pass the EIC allele to offspring.

EIC Carrier (N/EIC): One normal, one mutant copy. The dog does not develop EIC under normal circumstances but can pass the allele to offspring. Carrier x carrier pairings produce an expected 25% affected offspring.

EIC Affected (EIC/EIC): Two mutant copies. The dog will collapse with intense exercise. For working dogs intended for field competition, this is a significant limitation.

Breeding Recommendations

Do not breed two EIC carriers or affected dogs together. Carrier x clear pairings are acceptable and produce no affected offspring. For working/field-line Labs, reducing the prevalence of the EIC mutation is an ongoing effort — testing both parents before breeding is strongly recommended.

Testing

EIC DNA testing is available from Embark, PawPrint Genetics, Optigen, and the University of Minnesota lab (where the mutation was originally characterised). OFA publishes EIC results when submitted. Verify a stud's EIC status at ofa.org before breeding, especially for working or field-line Labradors.