What effect does high altitude diving have on the body?

High altitude diving significantly influences the body due to reduced air density. At higher elevations, the atmospheric pressure decreases, leading to lower partial pressures of gases, including oxygen and nitrogen. This change means that the amount of dissolved gases available in the body's tissues is altered. As a result, divers at high altitudes may experience increased risks of decompression sickness and altered physiological responses due to these lower gas pressures.

While factors such as increased buoyancy or decreased fatigue might seem relevant, they do not represent the main physiological impact of high altitude diving. The reduction in oxygen levels in the tank also doesn't accurately describe the effect on the body, as it is more about the external environmental conditions affecting gas exchange and metabolism in divers. Hence, the primary effect attributed to high altitude diving is indeed the reduced air density and its associated implications for the body.