At which heights have people got altitude sickness, curious what the lowest point would be that people know of ?

8000 feet: 8000 feet is the norm at which people may begin to notice significant symptoms but at 5000 feet many are breathless ; those who are very susceptible may complain of headache or occasional nausea. More serious high altitude pulmonary edema or high altitude cerebral edema emerge at higher altitude but it is speed of ascent rather than absolute height that increases risk.Danger very high > 11, 500 fee.