Common body temperature sites provide invalid measures of body core temperature in hyperthermic humans wearing American football uniforms

Figures & data

Table 1. Participant demographics and descriptive information

Demographics
Age (y)	22 ± 2
Height (cm)	181.3 ± 5.7
Sum of Skinfolds (mm)	26 ± 9
Body Density (g·cc^−1)	1.08 ± 0.01
Body Fat (%)	7 ± 3
Body Surface Area (m^2)	1.98 ± 0.13
Pre-exercise Urine Specific Gravity	1.007 ± 0.005
Pre-exercise Body Mass (kg)	77.5 ± 8.8
Post-exercise Body Mass (kg)	76.3 ± 8.6
Sweat Rate (L·h^−1)	1.76 ± 0.57
Hypohydration (%)	1.6 ± 0.5
Participants who reported shivering during CWI (n)	4 of 13
Self-reported shivering onset during CWI (min)	7.4 ± 2.8
Testing Conditions
Environmental Chamber Temperature (°C)	38.7 ± 0.8
Environmental Chamber Humidity (%)	38.9 ± 2.4
Water Bath Temperature, Pre-immersion (°C)	10.0 ± 0.1
Water Bath Temperature, Post-immersion (°C)	10.65 ± 0.2

Data are reported as means and standard deviations (n = 13). CWI = cold water immersion

Figure 1. Body temperatures measured in the rectum, mouth, axilla, forehead, and ear during rest, exercise, cold-water immersion, and post-immersion recovery in the heat. ^a = Rectal different than all other measurements except forehead. ^b = Rectal different than all other measurement sites. ^c = Rectal different than all other measurements except aural. ^d = Rectal different than axillary and oral measurements. All data are means ± SD, n = 13. Suprascripts indicate P < 0.05

Table 2. Bias from rectal temperature (°C) during four experimental time periods

					Overall Mean (time period) #
	Axillary	Oral	Forehead	Aural
Rest	1.1 ± 0.4	0.8 ± 0.4	−0.5 ± 0.6	0.3 ± 0.2	0.4 ± 0.7
Exercise	1.0 ± 0.5	0.9 ± 0.4	−0.7 ± 0.5	0.1 ± 0.3	0.3 ± 0.8
Cooling	11.8 ± 5.5 ¥	1.6 ± 0.4	0.6 ± 0.5	1.1 ± 0.4	3.8 ± 5.4
Post-immersion	4.8 ± 2.5 ¥	0.9 ± 0.4	−0.5 ± 0.5	0.5 ± 0.4	1.4 ± 2.4
Recovery
Overall Mean	4.7 ± 1.9	1.0 ± 0.2	−0.3 ± 0.4	0.5 ± 0.2
(body site) §

Data are means ± SD (n = 13). A positive bias indicates rectal temperature was higher than the other body site. # = The temperatures in this column are the average of all of the body temperature sites within each time period (i.e., the main effect of time).

¥ = Axillary different than all other body sites within these periods (P < 0.05). § = The temperatures in this row are the average of all measurements collected during the experiment from each body temperature site (i.e., the main effect of body site).

Figure 2. Bland-Altman plots indicating temperature bias between rectal temperature (T_REC) and aural temperature (T_EAR, A), oral temperature (T_ORL, B), axillary temperature (T_AXL, C), and forehead temperature (T_FHD, D) during rest, exercise, cold-water immersion, and post-immersion recovery in the heat. * = upper 95% limit of agreement; † = mean difference; ‡ = lower 95% limit of agreement

Availability of data and material

This data has not been published elsewhere nor is any data set available publicly at this time.