Purpose: To find out the relationship between duration of break, gender, age and the early physical conditions of the people who go to the Plateau again after the break. Means: The pre-work physical inspection data of 2528 people,who participated the construction on the Plateau (altitude 3080 m) during 2002-2004, and then returned during 2003-2005, were studied. Before the inspections, these people had been on the Plateau for 7～15 days to get them adaptable to the altitude conditions. These people were divided randomly into Long Break Group (break time≥90 d, n=984) and Short Break Group (break time ≤60 d, n=1544). Then they were divided into sub-Groups based on gender and age. Statistical analysis was then done using SPSS 12.0 software. Results: (1)The means of sBP,dBP,HR, and Hb of the Long Break Group, after 7～15 days of adaptability period, were lower than that of Short Break Group; while SpO2 of Long Break Group was slightly higher than that of Short Break Group.(Mean p≤0.001;The abnormal rates of ALT,BUN, BP of the Long Break Group were also significantly lower than that of Short Break Group (p<0.05, or p<0.001;(2)In the same group, or different groups, the BP,Hb of female sub-Group was better than male sub-Group(p<0.05, or p<0.001. The BP,ECG of <40 y sub-Group is better than ≥40 y sub-Group(p<0.05 or, p<0.001. Conclusion: 3-month, or even longer break in winter has positive impacts on the early physical conditions of the constructors on the Plateau (esp. males over 40 years old) Purpose: To find out the relationship between duration of break, gender, age and the early physical conditions of the people who go to the Plateau again after the break. Means: The pre-work physical inspection data of 2528 people, who participated the construction on the Plateau (altitude 3080 m) during 2002-2004, and then returned during 2003-2005, were studied. Before the inspections, these people had been on the Plateau for 7-15 days to get them adaptable to the altitude conditions. These People were divided randomly into Long Break Group (break time ≥90 d, n = 984) and Short Break Group (break time ≤60 d, n = 1544). Then they were divided into sub-Groups based on gender and age. Statistical analysis was then done using SPSS 12.0 software. Results: (1) The means of sBP, dBP, HR, and Hb of the Long Break Group, after 7-15 days of adaptability period, were lower than that of Short Break Group; while SpO2 of Long Break Group was slightly higher than that of Short Break Group. (Mean p 0.001; The abnormal rates of ALT, BUN, BP of the Long Break Group were also significantly lower than that of Short Break Group (p <0.05, or p <0.001; (2) In the same group, or different groups, the BP (P <0.05, or p <0.001. The BP, ECG of <40 y sub-Group is better than ≧ 40 y sub-Group (p <0.05 or, p <0.001. Conclusion: 3-month, or even longer break in winter has positive impacts on the early physical conditions of the constructors on the Plateau (esp. males over 40 years old)