Intermittent hypoxic training (IHT), also known as intermittent hypoxic therapy, is a non-invasive, drug-free technique aimed at improving human performance and well-being by way of adaptation to reduced oxygen.

Procedure

An IHT session consists of an interval of several minutes breathing hypoxic

Hypoxia (medical)

Hypoxia, or hypoxiation, is a pathological condition in which the body as a whole or a region of the body is deprived of adequate oxygen supply. Variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise...

 (low oxygen) air, alternated with intervals breathing ambient or hyperoxic air. This procedure is repeated over a 45- to 90-minute session per day, with a full treatment course taking three to four weeks.

Standard practice is for the patient to remain stationary while breathing hypoxic air via a hand-held mask

Oxygen mask

An oxygen mask provides a method to transfer breathing oxygen gas from a storage tank to the lungs. Oxygen masks may cover the nose and mouth or the entire face...

. The therapy is delivered using a hypoxicator

Hypoxicator

A hypoxicator is a medical device intended to provide a stimulus for the adaptation of an individual's cardiovascular system by means of breathing reduced oxygen hypoxic air and triggering mechanisms of compensation...

 during the day time, allowing the dosage to be monitored. Biofeedback

Biofeedback

Biofeedback is the process of becoming aware of various physiological functions using instruments that provide information on the activity of those same systems, with a goal of being able to manipulate them at will...

 can be delivered using a pulse oximeter

Pulse oximeter

A pulse oximeter is a medical device that indirectly monitors the oxygen saturation of a patient's blood and changes in blood volume in the skin, producing a photoplethysmograph. It is often attached to a medical monitor so staff can see a patient's oxygenation at all times...

.

Effects

The phenomenon of IHT is that it delivers a non-damaging training stimulus that naturally triggers a cascade of beneficial adaptive responses without adverse effects. The response is almost instant and is evident at various levels, from systemic

Systemic

Systemic refers to something that is spread throughout, system-wide, affecting a group or system such as a body, economy, market or society as a whole. Systemic may also refer to:-In medicine:...

 down to cellular

Cell (biology)

The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

. Treatment dosage of IHT can be measured and expressed using the hypoxic training index

Hypoxic Training Index

The Hypoxic Training index provides an objective measure of the hypoxic stress delivered during the Intermittent Hypoxic Training session, compared to simple recording the inhaled fraction of oxygen . HTi provides a figure of dosage received by the individual at the end of the session...

.

It is important to differentiate between physiological adaptations to mild hypoxia and re-oxygenation episodes (i.e., the IHT protocol) and frequent nocturnal suffocation awakenings produced by sleep apnoea, which might result in various pathologies.

Usage

When used for performance enhancement in sports settings IHT improves mitochondrial status, leading to improvements in aerobic

Aerobic exercise

Aerobic exercise is physical exercise of relatively low intensity that depends primarily on the aerobic energy-generating process. Aerobic literally means "living in air", and refers to the use of oxygen to adequately meet energy demands during exercise via aerobic metabolism...

 and anaerobic

Anaerobic exercise

Anaerobic exercise is exercise intense enough to trigger anaerobic metabolism. It is used by athletes in non-endurance sports to promote strength, speed and power and by body builders to build muscle mass...

 performance.

IHT can be beneficial for the treatment of a wide range of degenerative disease

Degenerative disease

A degenerative disease, also called neurodegenerative disease, is a disease in which the function or structure of the affected tissues or organs will progressively deteriorate over time, whether due to normal bodily wear or lifestyle choices such as exercise or eating habits...

s, including:

• chronic heart and lung diseases
• hypertension
• asthma and chronic bronchitis
• liver and pancreatic diseases
• anxiety and depression
• iron-deficiency anaemia
• lack of energy and fatigue

IHT is contra-indicated in case of:

• acute somatic and viral diseases
• chronic obstructive pulmonary disease (COPD-II and COPD-III)
• chronic diseases with symptoms of decompensation or terminal illness
• individual intolerance of oxygen insufficiency
• cancer, unless IHT is prescribed by a doctor
• people with epilepsy, pacemakers or heart arrhythmias, unless treatment (including IHT) is under direct medical supervision.

Although there are no reported adverse effects with IHT, basic treatment protocol suggested by the manufacturer must be followed.