What concentration of oxygen may impair coordination in individuals with health issues?

Individuals with health issues may experience impaired coordination when the concentration of oxygen in their environment falls between 15% and 19%. This range is lower than the standard atmospheric oxygen level of approximately 20.9%. When oxygen concentration drops to this level, individuals—particularly those with pre-existing health conditions—might have difficulty maintaining proper bodily functions, including coordination and cognitive abilities. This impairment can be attributed to hypoxia, where the body does not receive enough oxygen to meet its needs, leading to symptoms such as dizziness, confusion, and decreased motor skills.

On the other hand, the other concentrations mentioned do not present the same risks. Concentrations below 15% pose a more severe risk of serious health effects, while levels above 19% are generally safe for healthy individuals. Thus, the specific range of 15% to 19% is where those with certain health conditions may start to notice a decline in coordination due to insufficient oxygen supply.