The effects of endurance exercise combined with high-temperature head-out water immersion on serum concentration of brain-derived neurotrophic factor in healthy young men

Figures & data

Figure 1. Illustration of the experimental set-up during both HOI-ex conditions.

Figure 2. Changes in serum BDNF concentration in response to the three experimental conditions. Data are presented as mean ± SD. *p < 0.01, compared with before immersion (pre). †p < 0.01, compared with 40 °C HOI and 23 °C HOI-ex. BDNF, brain-derived neurotrophic factor; 40 °C HOI, head-out water immersion at 40 °C; 40 °C HOI-ex, cycling ergometer exercise in combination with head-out water immersion at 40 °C; 23 °C HOI-ex, cycling ergometer exercise in combination with head-out water immersion at 23 °C; pre, 30-min rest period prior to immersion; post, immediately after the completion of 15-min immersion protocol; post 15, 15 min after the immersion protocol; post 30, 30 min after the completion of immersion protocol.

Figure 3. Changes in core temperature during the three experimental conditions. Data are presented as mean ± SD. *p < 0.01, compared with before immersion (pre). †p < 0.01, compared with 40 °C HOI and 23 °C HOI-ex. 40 °C HOI, head-out water immersion at 40 °C; 40 °C HOI-ex, cycling ergometer exercise in combination with head-out water immersion at 40 °C; 23 °C HOI-ex, cycling ergometer exercise in combination with head-out water immersion at 23 °C; pre, 30-min rest period prior to immersion; post, immediately after the completion of 15-min immersion protocol; post 15, 15 min after the immersion protocol; post 30, 30 min after the completion of immersion protocol.

Table 1. The change in physiological parameters in response to the three experimental conditions.

	40 °C HOI				40 °C HOI-ex				23 °C HOI-ex
	Pre	Post	Post15	Post30	Pre	Post	Post15	Post30	Pre	Post	Post15	Post30
Heart rate (beats/min)	66.1 ± 10.7	102.5 ± 19.1**	81.1 ± 17.1**	77.1 ± 12.7*	67.6 ± 10.0	183.5 ± 16.7**††	122.8 ± 17.1**††	113.6 ± 20.4**††	65.8 ± 7.7	129.0 ± 12.4**	82.5 ± 9.8*	76.4 ± 10.1
Systolic blood pressure (mmHg)	116.8 ± 9.3	119.1 ± 8.2	116.4 ± 5.9	118.4 ± 4.7	118.5 ± 6.4	114.6 ± 11.3	111.2 ± 8.0	107.0 ± 6.2	119.8 ± 5.5	127.8 ± 15.0	125.9 ± 12.0	121.8 ± 11.6
Diastolic blood pressure (mmHg)	78.1 ± 7.7	71.0 ± 5.2	65.4 ± 6.5	73.1 ± 7.6	77.8 ± 5.0	59.3 ± 8.7**††	59.0 ± 5.7**††	59.8 ± 6.1**††	76.6 ± 4.8	80.6 ± 5.7	80.5 ± 6.9	82.4 ± 8.0
Hemoglobin concentration (g/dl)	15.7 ± 0.4	16.2 ± 0.5	16.1 ± 0.4	16.0 ± 0.3	15.2 ± 0.9	16.7 ± 1.0	16.3 ± 1.0	16.0 ± 0.9	15.3 ± 0.4	16.2 ± 0.6	15.7 ± 0.4	15.7 ± 0.4
Hematocrit (%)	44.9 ± 1.4	45.7 ± 1.7	45.6 ± 1.4	45.5 ± 1.5	44.1 ± 2.4	48.5 ± 2.2	46.9 ± 1.8	45.7 ± 1.9	44.5 ± 1.2	48.1 ± 1.7	46.1 ± 1.3	46.3 ± 1.3

Data are presented as mean ± SD.

*p < 0.05, **p < 0.01, compared with before immersion (pre).

†p < 0.05, ††p < 0.01, compared with 40 °C HOI and 23 °C HOI-ex.

HR: heart rate; SBP: systolic blood pressures; DBP: diastolic blood pressures; Hb: hemoglobin; Hct: hematocrit; 40 °C HOI: head-out water immersion at 40 °C; 40 °C HOI-ex: cycling ergometer exercise in combination with head-out water immersion at 40 °C; 23 °C HOI-ex: cycling ergometer exercise in combination with head-out water immersion at 23 °C; pre: 30-min rest period prior to immersion; post: immediately after the completion of the 15-min immersion protocol; post 15: 15 min after the completion of the immersion protocol; post 30: 30 min after the completion of the immersion protocol.

Figure 4. Changes in platelet counts in response to the three experimental conditions. Data are presented as mean ± SD. 40 °C HOI, head-out water immersion at 40 °C; 40 °C HOI-ex, cycling ergometer exercise in combination with head-out water immersion at 40 °C; 23 °C HOI-ex, cycling ergometer exercise in combination with head-out water immersion at 23 °C; pre, 30-min rest period prior to immersion; post, immediately after the completion of 15-min immersion protocol; post 15, 15 min after the immersion protocol; post 30, 30 min after the completion of immersion protocol.

Figure 5. Changes in P-selectin concentration in response to the three experimental conditions. Data are presented as mean ± SD. *p < 0.01, compared with before immersion (pre). †p < 0.01, compared with 40 °C HOI and 23 °C HOI-ex. 40 °C HOI, head-out water immersion at 40 °C; 40 °C HOI-ex, cycling ergometer exercise in combination with head-out water immersion at 40 °C; 23 °C HOI-ex, cycling ergometer exercise in combination with head-out water immersion at 23 °C; pre, 30-min rest period prior to immersion; post, immediately after the completion of 15-min immersion protocol; post 15, 15 min after the immersion protocol; post 30, 30 min after the completion of immersion protocol.

Table 2. Change in plasma cortisol and plasma lactate concentration following the three experimental conditions.

	40 °C HOI				40 °C HOI-ex				23 °C HOI-ex
	Pre	Post	Post15	Post30	Pre	Post	Post15	Post30	Pre	Post	Post15	Post30
Cortisol (lg/dl)	6.8 ± 1.4	5.7 ± 2.5**	8.2 ± 2.6**	8.5 ± 2.8**	6.8 ± 1.3	13.4 ± 2.3**††	19.5 ± 2.3**††	19.7 ± 2.4**††	5.9 ± 2.1	8.1 ± 2.6**	7.3 ± 2.9**	6.2 ± 2.5
Lactate (mg/dl)	7.1 ± 2.2	8.4 ± 1.6	7.2 ± 1.5	6.9 ± 1.8	8.1 ± 2.1	88.7 ± 15.7**††	58.6 ± 11.6**††	36.7 ± 9.4**††	7.9 ± 2.4	39.0 ± 12.4**	22.7 ± 5.8**	14.6 ± 3.0

Data are mean ± SD.

*p < 0.05, **p < 0.01, compared with before immersion (pre).

†p < 0.05, ††p < 0.01, compared with 40 °C HOI and 23 °C HOI-ex.

40 °C HOI: head-out water immersion at 40 °C; 40 °C HOI-ex: cycling ergometer exercise in combination with head-out water immersion at 40 °C; 23 °C HOI-ex: cycling ergometer exercise in combination with head-out water immersion at 23 °C; pre: 30-min rest period prior to immersion; post: immediately after the completion of the 15-min immersion protocol; post 15: 15 min after the completion of the immersion protocol; post 30: 30 min after the completion of the immersion protocol.