Table 4.

Comparison of the serum TSH, FT4, and FT3 between degrees of exposure to environmental temperature in summer and winter seasons.

Parameters	Outdoor stay hour
	Slight	Good
TSH (mIU/l)
Summer	3.02 ± 2.01	2.72 ± 1.81	0.385
Winter	2.86 ± 1.91	2.52 ± 1.41	0.275
FT4 (ng/dl)
Summer	1.23 ± 0.15	1.22 ± 0.15	0.858
Winter	1.19 ± 0.16	1.21 ± 0.15	0.491
FT3 (pg/ml)
Summer	3.18 ± 0.42	3.30 ± 0.46	0.191
Winter	3.30 ± 0.34	3.49 ± 0.45	0.023
FT3/FT4 ratio
Summer	2.64 ± 0.442	2.76 ± 0.45	0.196
Winter	2.84 ± 0.44	2.94 ± 0.35	0.275

The parameters are expressed as the mean ± SD, and the means are compared using a Paired sample t-test.