Myths vs facts: FT4 and Sport

The question of myths vs facts regarding FT4 (free thyroxine) and sport is not addressed in the provided context. Generally, FT4 is a thyroid hormone regulating basal metabolic rate. A common myth is that intense exercise drastically raises FT4, boosting fat burning. In reality, studies show moderate effects: endurance exercise may slightly increase FT4, while overtraining often suppresses it. Another myth is that low FT4 always indicates hypothyroidism; in athletes, it can reflect a physiological adaptation (euthyroid sick syndrome) without requiring treatment. Fact: FT4 alone is not a reliable predictor of athletic performance; assessment requires TSH, fT3, and clinical symptoms. The evidence is mixed – many studies are small or population-specific. Anyone checking hormone status in a sports context should discuss results with an endocrinologist, as reference ranges may differ for athletes.