past his prime
o The term low altitude refers to sites that are below 1500 meters (4920 ft). These sites are where most of the 7.5 billion of the world’s population reside. It is also the sites for most of the world’s athletics competitions. There are negligible physiological effects of hypobaria-hypoxia at this altitude.
o The reduction in PO2 at altitude affects the partial pressure gradient between the blood and the tissues and thus oxygen delivery. PO2 must fall below 131 mmHg (1500 meters [Table 1])) before VO2 max is affected. This explains the decrease in endurance sports performance at high altitude and above.
Altitude (meters) PB (mmHg) PO2 (mmHg)
0 (sea level) 760 159.2
1000 674 141.2
2000 596 124.9
3000 526 110.2
4000 462 96.9
9000 231 48.4
Table 1. Altitude and its effects on atmospheric (barometric) pressure and O2 partial pressure.
o Above 1500 meters (4921 ft), the decline in maximal aerobic power due to altitude exposure equals approximately 3% per 300 meters; this effect is absent below 1500 meters.
Looks like 1500m is more a measure of convenience than a well-established fact. The Albuquerque Convention Center is barely over 1500m of elevation, yet the howling about running distance at altitude commences as soon as a USATF or NCAA indoor championship event is scheduled for that venue.
The NCAA altitude conversions--which aren't necessarily the final word on any of this but do have some research behind them--go down to 3000 feet of elevation.