Experimental Procedure
The physiological parameters and EEG were recorded at four stages. The
first test (Test 1) was performed at Xiamen (63 m) approximately one
week before participants ascended to HA. After three days on train, all
participants arrived in Lhasa (Altitudes: 3658 m) and stayed for two
days. Subsequently, the participants stayed in Damxung County
(Altitudes: 4300 m) for three weeks, then returned to Lhasa for three
days and performed the second test (Test 2) in Lhasa. The third test
(Test 3) was conducted within one week after the subjects returned to
Xiamen. The last test (Test 4) was performed one month after
participants returned to Xiamen (Figure 1).