[Effect of heat acclimatization training on inflammatory reaction and multiple organ dysfunction syndrome in patients...

To investigate the effects of heat acclimatization training on the inflammatory reaction and multiple organ dysfunction syndrome (MODS) in patients with exertional heat stroke (EHS).

600 officers and soldiers from a special team who participated in 5 km armed wild training from June to July 2017 were selected as the research object, while 30 healthy officers and men who did not participate in armed wild training during the same period were selected as normal controls. The officers and soldiers who participated in 5 km armed wild training (ambient temperature > 35 centigrade, humidity > 65%, 2-3 times a week for 3 weeks) were divided into heat acclimatization group and non-acclimatization group, with 300 in each group. The heat acclimatization group first took part in the heat acclimatization training of wild or long distance running (the initial temperature was 30 centigrade, gradually transferred to the hot time of 37 centigrade), 2 hours each time, twice a day, and 5 days a week, for a total of 2 weeks. Venous blood was taken before and after heat acclimatization training, before armed wild training, and after the last training or EHS onset, and the contents of serum interleukin (IL-1β, IL-10), tumor necrosis factor-α (TNF-α) and γ-interferon (IFN-γ) were detected by enzyme linked immunosorbent assay (ELISA). The occurrence of EHS and MODS in EHS patients were recorded.

There was no significant difference in serum inflammatory factors between the officers and soldiers who participated in the training and the healthy control group before heat training or cross-country training. Compared with those before heat training, IL-1β, TNF-α, IFN-γ were significantly increased in all participants of heat acclimatization training while IL-10 was significantly decreased. For those who experienced premonitory (6 cases) and mild (2 cases) heatstroke during training, they could return to normal without severe heatstroke or EHS within 10-30 minutes after being immediately put in a cool and ventilated place and given anti-heatstroke drugs and other interventions. Compared with those before wild training, the levels of inflammatory factors in the two groups of officers and soldiers also changed after wild training, but the increase or decrease of inflammatory indexes in the heat acclimatization group were significantly smaller than those in the non-acclimatization group [IL-1β (ng/L): 10.65±5.18 vs. 12.13±7.91, TNF-α (ng/L): 14.60±5.79 vs. 16.27±8.52, IFN-γ (ng/L): 13.66±5.43 vs. 15.33±8.71, IL-10 (ng/L): 8.22±2.68 vs. 7.13±2.63, all P < 0.05]. During armed wild training, a total of 27 cases of EHS occurred. The incidence of EHS in the heat acclimatization group was significantly lower than that in the non-acclimatization group [2.67% (8/300) vs. 6.33% (19/300), χ² = 4.693, P = 0.030]. In patients with EHS, IL-1β, TNF-α, IFN-γ after wild training in the heat acclimatization group were also significantly lower than those in the non-acclimatization group, and IL-10 was significantly higher [IL-1β (ng/L): 34.50±3.74 vs. 39.53±4.51, TNF-α (ng/L): 43.75±2.87 vs. 46.79±2.66, IFN-γ (ng/L): 40.25±1.75 vs. 46.58±1.92, IL-10 (ng/L): 7.50±2.45 vs. 5.42±1.80, all P < 0.01], and the incidence of MODS and organ involvement of EHS patients in the heat acclimation group were significantly lower than that in the non-acclimatization group [50.00% (4/8) vs. 89.47% (17/19), χ²= 5.075, P = 0.024; 28.13% (9/32) vs. 47.79% (65/136), χ²= 4.066, P = 0.044].

Heat acclimatization training before high strength training in high temperature and humidity environment can effectively reduce the degree of inflammation reaction of EHS, protect the physiological functions of EHS organs, and reduce the incidence of MODS.