Table 3.

Environmental conditions at the heart rate and core temperature inflection point for each experimental condition

	34°C	36°C	38°C	40°C	20 mmHg	16 mmHg	12 mmHg
MinAct
	n = 8	n = 11	n = 8	n = 9	n = 7	n = 13	n = 13
Tdb, °C
HR	–	–	–	–	42.2 ± 2.2*	43.6 ± 2.8*	46.8 ± 2.7*
Tgi	–	–	–	–	43.9 ± 2.1	46.3 ± 2.0	49.4 ± 2.6
Pa, mmHg
HR	29.0 ± 1.6†	27.4 ± 2.4†	28.0 ± 2.3†	25.3 ± 2.7†	–	–	–
Tgi	32.3 ± 1.6	29.9 ± 2.1	29.8 ± 2.3	27.7 ± 2.4	–	–	–
rh, %
HR	72.9 ± 5.1ϕ	61.7 ± 5.3ϕ	56.8 ± 5.2ϕ	45.2 ± 5.0ϕ	31.7 ± 3.3	24.0 ± 3.0	15.4 ± 2.1
Tgi	80.9 ± 4.1	67.3 ± 4.8	60.5 ± 5.1	50.2 ± 4.3	29.1 ± 2.7	21.1 ± 1.6#	13.7 ± 2.0#
LightAmb
	n = 14	n = 9	n = 7	n = 8	n = 10	n = 17	n = 19
Tdb, °C
HR	–	–	–	–	37.6 ± 1.7*	39.7 ± 2.1*	40.6 ± 2.1*
Tgi	–	–	–	–	39.1 ± 1.0	42.2 ± 1.7	43.7 ± 2.0
Pa, mmHg
HR	21.6 ± 3.3†	21.6 ± 1.8†	22.0 ± 2.2	18.7 ± 3.8†	–	–	–
Tgi	24.1 ± 3.1	24.3 ± 1.5	23.3 ± 0.7	21.0 ± 1.7	–	–	–
rh, %
HR	53.7 ± 7.7ϕ	48.9 ± 4.1ϕ	44.0 ± 4.5	33.7 ± 6.9ϕ	40.8 ± 3.8	29.6 ± 3.3	21.2 ± 2.6
Tgi	60.7 ± 8.0	54.8 ± 3.3	46.6 ± 2.1	37.9 ± 3.0	37.9 ± 1.6#	25.9 ± 2.5#	18.7 ± 2.4#

Values are represented as means ± SD. Data were analyzed using a paired-samples t test; n represents number of subjects *P < 0.05 compared with T_db at T_gi inflection; †P < 0.05 compared with p_a at T_gi inflection; ϕP < 0.05 compared with rh at T_gi inflection; #P < 0.05 compared with rh at HR inflection. LightAmb, light ambulation; MinAct, minimal activity; P_a, ambient water vapor pressure; rh, relative humidity; T_db, dry-bulb temperature; T_gi, gastrointestinal temperature.