difficulty breathing, can't take a deep breath. struggle breathing during low impact activities
Paleness/Blueness Lack of energy, feeling tired all the time. Sleeping more, see above. Breathing more rapidly. Increased heart rate.
Low Oxygen saturation or hypoxia is a low level of Oxygen in the blood stream not to be confused with oxygen bound to haemoglobin
if levels are low more about a minute or so you may experience a light headed feeling, or dizziness. if low levels are breathed for a prolonged period of time symptoms may become sever. lack of focus...
pneumonia
How to Combat Altitude Sickness
How to Prevent Altitude Sickness
Melissa's Breathing Problems in High Altitude
The Dangers of Respiratory Distress Syndrome in Newborns