title: Serum thyroxine, triiodothyronine and thyroid stimulating hormone after prolonged heavy exercise.
abstract: Serum thyroxine (T4), triiodothyronine (T3) and thyroid stimulating hormone (TSH) was measured before, immediately after and on the following days after a 70 km cross-country ski race in two groups of ten well-trained men, one aged 21--29 years, taking 5.01--7.03 h, and one aged 51--57 years, taking 6.07--7.38 h. T4 was definitely increased immediately after the race, but fell to below the initial level on the following day and was not restored to the pre-race level until 4 days after the race. T3 showed essentially the same pattern, though less pronounced, a major part of the changes being possibly due to plasma volume variations. TSH showed a tendency to rise immediately after the race, but rose further to 175% of the initial level on the following day and was not restored to the initial level 4 days after the race. The pattern of changes were independent of age. It is suggested that the prolonged rise in TSH is probably due to an exercise-induced increased peripheral need for thyroid hormone.
mesh_terms: D000328:Adult; D001798:Blood Proteins / Q000378:metabolism; D006400:Hematocrit; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D005082:Physical Exertion; D010809:Physical Fitness; D012709:Serum Albumin / Q000378:metabolism; D012865:Skiing; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
chemical_list: D001798:Blood Proteins; D006454:Hemoglobins; D012709:Serum Albumin; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine