How are IgG and Sport related?

The relationship between IgG and sport is complex and often misunderstood. IgG (Immunoglobulin G) is an antibody that plays a key role in immune defense. Intense exercise can transiently lower IgG levels (the 'open window' theory), potentially increasing infection risk. Conversely, IgG4 is frequently linked to food sensitivities – some athletes use IgG4 tests to identify foods that might impair performance. However, scientific evidence for this is weak: IgG4 tests are not validated for diagnosing intolerances, and major allergy organizations advise against them. MyBody-X does not offer IgG testing; its tests focus on genetics, metabolism, and microbiome. Athletes aiming to optimize immune function should prioritize balanced nutrition, adequate sleep, and moderate training rather than unproven IgG-based dietary restrictions.