I choose Warning @ Dangers to post this is only because I want to get your attention here.

If you go to Huanglong valley, 155 miles away from Chengdu, please take the altitude into consideration. For most travellers can not resist the appealing of Huanglong Temple on the summit and the most beautiful five color pool at its back. It really deserves for a bight-yellow temple atop surrounded by mountains creat a harmony between the temple and the nature. But remember the Huanglong Temple is over 3300 meters above the sea level. Mountain sickness would be a problem for some people. I saw many middle-aged tourists carrying oxygen with them! I am near my thirty years old and i had a test. Jogging caused me run out of breath and the best speed is that of walking. I got a ten-second headache when I arrived the top.

The whole climbing is physically demanding for those persons who do not do any excercise!