Winning a Nobel Prize is a goal few scientists could ever dream of setting themselves, and one even fewer could imagine winning. Many would describe it as the pinnacle of a career in the sciences. Now, a group of scientists including Sir Peter Ratcliffe at the Francis Crick institute in London have been awarded the prestigious prize for their research investigating how our cells sense oxygen.

When you train at altitude, the amount of oxygen available to you falls. As a result, the amount of oxygen in your blood also falls. We call this spO2, which can be considered the percentage of your red blood cells that are saturated with oxygen. This drop in blood oxygen saturation is a stimulus for your body to adapt, and is the reason why you gain more benefit from a session at altitude than the equivalent session undertaken at sea level.


Since the early 1990’s, scientists have been uncovering the genetic and molecular basis for this. In 1992, a group of scientists in Maryland discovered a protein which is produced when your body is exposed to the lack of oxygen at altitude. They named this hypoxia inducible factor 1 (HIF1), and subsequent research has implicated HIF1 in a range of benefits seen when training at altitude. However, exactly how HIF1 senses oxygen has remained unclear… until now.

And this is where the science gets even deeper. Ratcliffe and his colleagues showed that, at sea level, a specific type of HIF1 called HIF1a is modified by enzymes which cause it to bind to another protein. Eventually, this leads to the destruction of HIF1a. At altitude however, these enzymes are inactive due to the lack of oxygen. This means that, rather than being destroyed, HIF1a builds up in our cells. In the nucleus of our cells, HIF1a combines with HIF1b and together they act on your DNA, switching on and off hundreds of genes including the one for erythropoietin (EPO) and causing you to get the gains from altitude.


The researchers hope that this knowledge can be used to begin further research into life-saving medicine for cancers, anaemia, and other chronic diseases. For mountaineers this offers new insight into preparation for and physiological management of long expeditions to severe altitude, where acute and chronic mountain sickness have previously proved debilitating. Meanwhile athletes and coaches now have a stronger understanding of how the body works under hypoxic conditions at altitude, and how we can use this to our advantage for performance improvement.

Interested in trying altitude training for yourself? Click here to find out more about our exercise sessions at altitude and here for information on the POD, where we can simulate extreme altitude. Interested in the research? You can read more on the science behind altitude adaptations online here.