Intermittent Hypoxic Exposure
Being exposed to low oxygen for short periods has been shown to provide additional benefits beyond other Altitude Training Approaches. The technique usually involves Breathing air with reduced oxygen content for shorter periods. IHE can provide the increase in red blood cell count as longer periods, as well as improving oxygen delivery to the muscles. IHE is normally performed at rest rather than when training, and uses a Pulse Oximeter to verify the impact of the hypoxia. Also, IHE uses lower oxygen content than other forms of altitude training. For details of the supporting studies for IHE, see The Science of Intermittent Hypoxic Exposure. It is also possible to exercise while exposed to lower oxygen levels, referred to as Intermittent Hypoxic Training.
1 Benefits of IHE
- Improved efficiency in oxygen usage (mitochondrial respiration)
- Increased blood oxygen carrying capacity (not all studies show this)
- Greater resistance to free radicals through improved anti-oxidant defenses
- Adaption in Breathing patterns at altitude
- A shift from Protein to fat as an energy source
- No reduction in training intensity compared with Live High, Train High
- No impaired sleep compared with Live High, Train Low
- Improved lung function for patients with bronchial asthma and chronic obstructive pulmonary disease (COPD).
- Some positive studies of the effect of IHE on Parkinson's Disease, Alzheimer’s Disease, and Cancer using animals.
2 Altitude Training Regime
With an IHE regime you can vary how long the hypoxia periods last for, how long the recovery period lasts for, the number of hypoxic bouts, and either the oxygen level or the target SpO2. There is no clear direction on the best combination, but here are some general guidelines.
- Typically the hypoxic period lasts between 3 and 15 minutes.
- Recovery periods are either equal to the hypoxic periods or shorter.
- Bouts of hypoxia are repeated to give anywhere from 20-90 minutes of total hypoxic time.
- The target SpO2 is generally between 85 and 75%. Saturations over 90% do not have any significant impact, and going below 75% is not advised.
- IHE can be performed daily or for just a few days per week.
- An IHE program will often build up the duration and SpO2 over time.
- During a Taper the IHE is either reduced or stopped.
- Some people find that beginning an IHE routine can make them feel sluggish, as you might expect with a new training stress.
- There is a wide individual variability in altitude adaptation.
A pattern that is used by a number of studies is IHE for 15 days, with 6 repeats of 5 minutes hypoxic plus 5 minutes recovery (total 30 minutes hypoxia).
- Days 1 to 5: saturation = 90, 88, 86, 86, 84%. (Using a percentage O2 of 12%.)
- Days 6 to 10: saturation = 82, 82, 80, 80, 78%; (Using a percentage O2 of 11%.)
- Days 11 to 15: saturation = 78, 78, 76, 76, 76%; (Using a percentage O2 of 10% then 9%.)
After this 15 day period there are a number of options depending on your goal:
- For a race, have 3-4 days with no IHE, then the race on the 5th day.
- Use IHE periodically, doing 5-7 days of IHE then 10-15 days without IHE.
- Continue using IHE 3-7 days/week indefinitely. The length of the IHE could be reduced to 15 minutes of hypoxia as either 1x15 minutes or 3x (5 minutes hypoxia plus 5 minutes recovery).