Thank you for asking!
That is quite a variable time frame depending upon the health of individual, extent of altitude and many associated factors which then decide what will be the time frame. Usually it takes maximum 7 days to 14 days to acclimatise.Everyone traveling to altitude is at risk, regardless of age, level of physical fitness, prior medical history, or previous altitude experience.
The high-altitude environment generally refers to elevations over 1500 m (4900 ft). Moderate altitude, 2000-3500 m (6600-11,500 ft) includes the elevation of many US ski resorts. Although arterial
oxygen saturation is well maintained at these altitudes, low PO2 results in mild tissue
hypoxia, and
altitude illness is common. Very high altitude refers to elevations of 3500-5500 m (18,000 ft). Arterial oxygen saturation is not maintained in this range, and extreme
hypoxemia can occur during sleep, with exercise, or illness. HACE and HAPE are most common at these altitudes. Extreme altitude is over 5500 m; above this altitude, successful long-term acclimatization is not possible and in fact deterioration ensues. Individuals must progressively acclimatize to intermediate altitudes to reach extreme altitude.
I hope it helps.Seek your doctor for further management.
take care