Hypoxic training is a method of training that lowers the availability of oxygen to the body.

Some people , including many athletes, believe that it can lead to physiological changes that allow the blood to carry more oxygen and thereby improve physical endurance.

The question is – does this theory hold water? Because of the inconclusive nature of the studies done so far, the answer to that question is still up in the air.

What scientists do know is that constant exposure to low levels of oxygen can do more harm than good to the body. It can cause  chronic stress, detraining, and edema (fluid buildup in the lungs and brain).

In some cases, blood can thicken too much, raising the risk of death due to blood clotting.

A number of athletes, however, have found that intermittent hypoxic training in combination with regular training has improved their level of performance.

Others feel that sleeping or living at high altitudes (or simulated high-altitude environments) and training at low altitudes increases their endurance.

This is known as the LHTL (Live High Train Low) method and is supposed to counteract the effects of detraining while enhancing performance by an typicalof 2 to 3%.

Heading for the hills isn’t the only way to achieve the effects of hypoxic training.

As you mentioned, there are now quite a few ways to simulate high altitude training, like breathing intermittently with a nitrogen mask, sleeping in a nitrogen tent, living or sleeping in a barometric chamber, and living in a nitrogen house.

Nitrogen replaces a proportion of the oxygen in the air in many of these methods, leading to oxygen deprivation and thus creating a hypoxic environment.

Nevertheless, all these tools come with disadvantages and might not work for everyone, so it’s best to consult with a health care provider when you are thinking of using them.