Effects Of Cold Exposure On Maximal Oxygen Uptake And Oxygen Supply Transport

Research purpose:To compare the differences in the maximum oxygen uptake level of healthy adults under different environmental temperatures,to explore the effects of low temperature exposure on oxygen uptake,oxygen transport and oxygen utilization,and to explore the underlying reasons why low temperature affects the maximum oxygen uptake level.Research method:32 college students(male 17 and female 15)were selected as the research objects.Measure the maximum oxygen uptake levels of male and female under normal temperature(22 ±1.2 ℃,52 ± 5.2%)and low temperature(-6.8±1.6℃,66 ± 5.7%)exposure conditions.By analyzing and comparing changes in lung ventilation function indexes,blood oxygen saturation,muscle oxygen content and blood biochemistry,observe the effects of low temperature exposure on external respiration,gas transport and internal respiration.Research results:① Low temperature significantly increased the maximum oxygen uptake(VO2max)of people of different genders(P<0.05);there was no difference in the increase of maximum oxygen uptake between different genders.②Low temperature significantly increased the oxygen uptake(VO2)of all subjects during resting and exercise(P<0.05).③ At rest,low temperature significantly increased male’s minute ventilation(VE),exhaled carbon dioxide(VCO2),and alveolar ventilation(VA)(P<0.05),and significantly reduced oxygen equivalent ventilation(VE/VO2),carbon dioxide ventilation equivalent(VE/VCO2)(P<0.05);while low temperature did not significantly affect female’s VE and VCO2,but only significantly reduced VE/VO2 and VE/VCO2(P<0.05).④When exercising in low temperature environment,male’s VE,VCO2 and VA increased significantly when reaching lowintensity exercise,VE/VO2 decreased significantly throughout the exercise,and VE/VCO2 was low significantly increased when reaching low intensity exercise(P<0.05).⑤When exercising in low temperature environment,female’s VE,VCO2,and VA increased significantly from moderate to high intensity exercise(P<0.05),VE/VO2 were significantly reduced,and VE/VCO2 was significantly reduced from moderate to moderate intensity(P<0.05).⑥At rest,low temperature significantly increased the heart rate(HR)of all obesity,and significantly increased the oxygen pulse(VO2/HR)of men(P<0.05);at maximum exercise intensity,low temperature significantly reduced subjects’ HR and VO2/HR increased significantly(P<0.05).During resting and exercise,low temperature has no significant effect on the arterial oxygen saturation(SaO2).⑦At rest,low temperature significantly reduces 2,3diphosphoglycerate(2,3-DPG)in subjects.At maximum exercise intensity,hypothermia significantly reduced the core body temperature(Tes)of male(P<0.05),but there was no significant change in female.During rest and maximum exercise,low temperature did not significantly affect the blood lactic acid(BLa)concentration.⑧At rest,low temperature significantly reduced the skeletal muscle oxygen saturation(TSI)of all subjects(P<0.05).During exercise,male’s relative decrease in muscle oxygen content(ATSI)begins to increase significantly during high-intensity exercise(80-100%V02max),and female’s ATSI begins to increase significantly at mediumintensity(50-100%V02max)(P<0.05).Research conclusions:①Low temperature can increase the maximum oxygen uptake level,and there is no significant difference between different genders.First of all,low temperature can increase the ventilation volume,deepen breathing,increase ventilation efficiency,and improve the level of lung ventilation;second,low temperature exposure can the efficiency of blood transport of oxygen;finally,although low temperature exposure is not conducive to oxygen dissociation,chills and heat production will increase the level of muscle oxygen utilization.Low temperature can slow down muscle fatigue during exercise and accelerate the recovery of fatigue,which is beneficial to muscle performance.② Affected by different anthropometric characteristics,people of different genders have different degrees and time of response to low temperature stimulation.The response time of women to low temperature stimulation is relatively slow.The body response is lower than that of men during resting and low-intensity exercise,and the body response is higher than that of men at medium and high intensity.Therefore,under low temperature stimulation,the increase in maximum oxygen uptake is more consistent.