Sweat iodine loss

Over a prolonged period of exercise, sweat iodine losses would result in a significant depletion of thyroidal iodine stores. 

Sweat weight (g) Time (h) Iodine cone, (gg/l) Total iodine loss (iig)... 

Such losses may be negligible in those parts of the world where diets are iodine-replete and intrathyroidal iodine and thyroid hormone stores abundant. However, in areas of iodine deficiency, overt or borderline, the additional stress of iodine loss in sweat may have relevance to thyroid status (Smyth and Duntas, 2005). It is this possibility which is the subject of the present study. 

Table 59.3 Iodine loss (urine + sweat) in training athletes and controls...

In the absence of definitive evidence that iodine loss through excessive sweating can induce a relative iodine deficiency with consequences for thyroid hormone formation, there is not as yet a case for iodine supplementation of those involved in vigorous exercise. However, the... 

Asa published sweat iodine concentration of35—40 p,g/l sweat losses of 4—5 liters would involve iodine losses equivalent to the WHO-recommended adult daily iodine intake ( 150 p,g). 

Iodine losses in sweat may not be independent of dietary iodine intake. 

Perhaps the most ambitious early effort of this type was the model of iodine metabolism developed by Douglas Riggs (1952). He presented a theoretical model that included ingestion of iodine as iodide, its absorption into the plasma, and transfer to the thyroid and other tissues, with loss through the kidneys, sweat and expired air. Within the thyroid gland, he described the organification of iodine and production of monoiodothyronine, diiodothyronine, and thyroxine (T4) on the framework of thyroglobufln. 

Hyperthyroidism The result of excessive circulating thyroid hormone with nervousness, sweating, tremor, with a rapid heart rate and loss of weight ICCIDD International Council for Control of Iodine Deficiency Disorders-an international non-government organization made up of a network of 700 health professionals from more than 90 countries available to assist IDD elimination programs in affected countries... 

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