To compare the differences in the measurement of maximum quantity of respiratory oxygen (VO2max) between direct and indirect methods, we selected 30 male students from the College of Physical Education, Hunan Normal University including 15 football players and 15 track and field players in November 2006. The VO2max was measured directly with the cardio-pulmonary function test, and measured indirectly with Doblen step test. The results showed that the VO2max measured by indirect method was higher than that by direct method [(3.70?0.56), (3.30?2.61) L per minute, P

BACKGROUND: Many experiments have proved that heavy-load movement training causes the acute increase of free radicals. The increase of endogenous free radicals and caused cellular and subcellular lipid peroxidation strengthening injure the structure and function of tissue cells, thereby, decrease motor ability. Sleep deprivation also causes the increase of oxygen free radicals.OBJECTIVE: To observe the changes in malondialdehyde (MDA) and glutathione (GSH) levels as well as superoxide dismutase (SOD) activity in serum of acute exhaustive exercise rats following different time periods of sleep deprivation.DESIGN: A randomized controlled animal experiment.SETTING: Laboratory of Exercise Sciences & Sports Medicine, Physical College, Hunan Normal University.MATERIALS: Thirty healthy male SD rats of clean grade, weighing about (220±13)g, provided by Experimental Animal Center of Hunan Agricultural University, were involved in this study.METHODS: This experiment was carried out in the Laboratory of Exercise Sciences & Sports Medicine, Physical College,Hunan Normal University from April 2006 to May 2006. Thirty rats were randomized into 5 groups: blank control group,simple exercise group, sleep deprivation 24 hours group, sleep deprivation 48 hours group and sleep deprivation 72 hours group, with 6 rats in each group; Rats in the blank control group were allowed to sleep normally, but not do exercise; Rats in the simple exercise group were allowed to sleep normally and executed after acute exhaustive exercise; Rats in the sleep deprivation 24, 48 and 72 hours groups were deprived their sleep for 24, 48 and 72 hours,respectively, then they were executed after acute exhaustive exercise. Method of gentle handling was used in creating rat models of sleep deprivation; Rats in the simple exercise group and sleep deprivation groups were forced to do exercise according to the rat exercise model project established by Bedford: treadmill gradient 10°, speed 19.3 m/min, all the exercise rats were exhaustive (Exhaustion criteria: At the end of exercise, rats reached 1/3 of runway over 3 times;Various stimulations for expelling were invalid. After running, rats presented with breathlessness, expression lassitude,ventral decubitus, slow stimulus response, weaker escape response in being captured). After experiment, rats in each group were executed under the anesthetic state, and their blood was taken out, and centrifuged after natural clotting.Supernatant fluid was taken for detecting MDA and GSH levels as well as SOD activity.MAIN OUTCOME MEASURES: Changes in MDA and GSH levels, and SOD activity in rat serum.RESULTS: Thirty rats were involved in the final analysis. ① MDA level in the simple exercise group was higher than that in the blank control group (P＜ 0.01). MDA level in the sleep deprivation 24 hours, 48 hours and 72 hours was higher than that in the simple exercise group, respectively (P ＜ 0.01). MDA level in the sleep deprivation 72 hours was statistically higher than that in the other sleep deprivation groups, respectively (P ＜ 0.01). ②GSH level in the simple exercise group was lower than that in the blank control group (P ＜ 0.01). GSH level in the sleep deprivation 24 hours group was higher than that in the simple exercise group [(P ＜ 0.01). GSH level in the sleep deprivation 24 hours and 48 hours groups was lower than that in the simple exercise group, respectively (P ＜ 0.05, 0.01). There were statistical differences in GSH level among sleep deprivation groups (all P＜ 0.01). ③ SOD activity in the simple exercise group was lower than that in the blank control group (P ＜ 0.01); SOD activity in the sleep deprivation 24, 48 and 72 hours groups was lower than that in the simple exercise group, respectively (P ＜ 0.01); SOD activity in the sleep deprivation 48 and 72 hours groups was significantly lower than that in the blank control group, respectively (P ＜ 0.01); There were statistical differences in SOD activity among sleep deprivation groups (P ＜ 0.01).CONCLUSION: Sleep deprivation can cause serumal oxidative stress injury of rats; With elongation of time of sleep deprivation and exhaustive exercise, oxygen free radical production in serum of rats accumulates more and more, ability to get rid of oxygen free radical becomes weaker and weaker, and injury to body is more and more obvious.Serumal oxidative stress status of acute exhaustive exercise rats following sleep deprivation