The effects of moderate altitude on circulating thyroid hormones and thyrotropin in training athletes.
OBJECTIVE
To study the effect of moderate altitude on thyroid hormones among training athletes.


METHODS
Serum total and free triiodothyronine (T3), thyroxine (T4), and thyrotropin (TSH) concentrations were measured among eight training athletes at sea level and subsequently during training for 12 days at the altitude of 1100-2700 m.


METHODS
Deaconess Institute of Oulu, and Division of Sports Medicine, Department of Physiology, University of Oulu, Finland.


METHODS
National top class skiers who normally live at sea level.


RESULTS
Serum concentrations of TSH, total and free T4, and reverse T3 did not change significantly. A significant decrease in serum total T3 levels from 1.9 nmol*1-1 on days 1-3 to 1.6-1.7 nmol*l-1 on days and 5-6 (p < 0.05) was observed. Serum albumin decreased (p < 0.05) on days 1-8 at altitude and correlated to serum total T3 (R = 0.36, p = 0.013). Serum free T3 increased steadily at moderate altitude and reached a significantly higher level (p < 0.05) at the end of the training period than before.


CONCLUSIONS
The serum free T3 increases when unacclimatized sea level skiers move to train at moderate altitude.
Koistinen
P
P
Health Centre Hospital of Oulu, Finland.
Martikkala
V
V
Karpakka
J
J
Vuolteenaho
O
O
Leppäluoto
J
J
D000328:Adult; D000531:Altitude; D005260:Female; D006801:Humans; D008297:Male; D013177:Sports / Q000502:physiology*; D013963:Thyroid Hormones / Q000097:blood*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D013963:Thyroid Hormones; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine