The aim of hypoxic training is to increase oxygen utilisation by the muscles to delay the switch from aerobic respiration of muscle to anaerobic respiration that produces lactic acid which accumulates in muscles causing fatigue.
Hypoxic training is the only practice that leads to significant improvements in all 3 stages of oxygen transport.
- Extraction of oxygen from the air in the lungs to the blood.
- Combination of the oxygen with haemoglobin on the red blood cells (RBCs) to transport the oxygen to the working muscles.
- Uptake and utilisation of oxygen by the muscle.
On return to racing in normoxic conditions, the 'extra' oxygen is then made available for energy metabolism and performance. Exposure to hypoxia stimulates up-regulation of Hypoxia Inducible Factor (HIF-1), which promotes an improvement of the body’s oxygen utilisation system at every link in the chain. Initially, pulmonary oxygen absorption is enhanced to allow more oxygen to enter the system. At the same time the kidneys signal for an increase in Erythropoietin Hormone (EPO) which stimulates the production of Red Blood Cells (RBCs) providing increased transportation for the extra oxygen throughout the body. At the next level, certain growth factors (VEGF) trigger increased capillarisation, enabling increased blood flow to tissues, muscles and brain. Finally, hypoxic training causes a boost in production and rejuvenation of mitochondria (the body’s principle oxygen sink and the location of aerobic energy production) and mitochondrial enzymes, allowing more efficient use of oxygen for energy production and enhanced enzymatic anti-oxidative defence.
Aside from these primary systemic changes, exposure to hypoxia is known to have the following beneficial physiological effects:
- Decreased average Heart Rate and Blood Pressure
- Increased production and release of Growth Hormone
- Stimulation of fat burning metabolism
- Decreased oxidative stress from Free Radicals (Reactive Oxygen Species “ROS”)
- Increased immune system response and improved cellular function and repair
Hypoxic training has revolutionised human athletic performance. It is an accepted training method that means anybody not using it immediately starts at a disadvantage.
Passive Hypoxic Conditioning
Often known as 'Sleep High, Train Low (SHTL)' this regime only requires the person to breathe hypoxic air whilst at rest, including when asleep. Just breathing hypoxic air lowers the oxygen level in the blood to much less than is possible even when exercising at maximum effort. Therefore, despite the fact that there is no physical activity, or feeling in any way uncomfortable, the hypoxic stress stimulates a cascade of physiological events which improve the entire oxygen delivery system. Many studies have shown that 8-12 hours of exposure per day or night for a period of three weeks will create sustainable benefits.
Beyond SHTL, Intermittent Hypoxic Training (IHT = Train High - breathing hypoxic air whilst on a treadmill or other static exerciser) can be used to specifically target core muscle groups. Research shows that this results in increased capillaries within the target muscles and increased mitochondria. The most effective regimes depend on the individual horse and the type of race or activity it will be participating in. Athletes already utilising hypoxic training to achieve performance benefits have reported help with
- Accelerating pre-season fitness training;
- Improved recovery;
- Improved ability to maintain high levels of fitness;
- Preventing or reducing respiratory problems;
- Maintaining cardio-vascular fitness in injured or “at risk” athletes forced to reduce training intensity;
- The final preparation for racing
With the ability to train the cardio-vascular system in hypoxic conditions rather than relying solely on long distance (and time) training sessions it is now possible to minimise the injury risk, ensuring that you will be more likely to compete in your target races.