The 1968 Mexico City Olympic Games have had sport scientists’ minds racing for decades.  It was an Olympics where some records were smashed beyond comprehension, and others were completely untouchable.

Why? The answer is up in the air. Literally. Mexico City sits 2,240 metres above sea level where the high altitude and thin air can wreak havoc on the human body.

For Professor Chris Gore, Head of Physiology at the Australian Institute of Sport (AIS), understanding the effects of altitude has become a fixation.

“It’s been my passion for 15 years. I think it’s fascinating and I’m always trying to find new ways to help athletes and coaches use altitude training more effectively.”

Professor Chris Gore, Head of Physiology at the Australian Institute of Sport

So what happens to the air at high altitudes to affect our bodies so much?

Any given volume of air is comprised of 79% nitrogen, 20.9% oxygen and 0.1% other gases such as argon and krypton. But as you get higher and higher above sea level, the pressure of the atmosphere decreases.

This is due to the effects of gravity (which keeps air close to the ground) and heat (as you get closer to the sun) which cause molecules to bounce off one other and expand. So as you reach higher altitudes, the air expands.

While the composition of the air stays the same, the expansion means that the air is ‘thinner’ – so in essence, at higher altitudes you inhale less oxygen and nitrogen molecules than you would at sea level.

This drives a cascade of physiological responses in the human body.  To begin with, your body increases its heart rate and respiratory rate to increase the amount of oxygen taken in and circulated around the body.  So for example, while an athlete might normally run with a heart rate of 150 beats per minute, at high altitude it might increase to 165.

Then the body begins to respond and adapt to the altitude (a process called acclimatization). More than 200 genes are turned on in response to altitude, and one that is most commonly thought of is that which induces the creation of more red blood cells thereby increasing the amount of hemoglobin in the blood.

Hemoglobin is the protein that binds oxygen molecules to red blood cells.  The more hemoglobin in the blood cells, the more efficient the cells will be at carrying oxygen around the body.  This means that even though less oxygen is taken into the lungs, it is more easily transported to the muscles.

Finally, as you breathe faster and faster, the amount of carbon dioxide in the blood is reduced, which leads to the blood becoming less acidic.  To counter this, the kidneys release blood bicarbonate to try to balance the PH level.  For athletes, this is a big advantage since blood bicarbonate is the primary source of protection for muscles against lactic acid – the waste that builds up during exercise and leaves muscles feeling stiff and sore.

While most of the scientific world has focused on the benefits of more haemoglobin following altitude training, Professor Gore and his colleagues have looked at the range of other effects.

His work has proven that muscle buffering capacity is improved and that blood lactate levels during exercise are lowered.  Additionally, the AIS scientists have found that athletes become more efficient after altitude exposure.  Just like high altitude natives, athletes are able to use less oxygen to do the same amount of work after they have been at simulated altitude.

The down side however, is that many of these physiological responses do not occur straight away.  It can take days, even weeks for the human body to fully adapt to the effects of altitude and for athletes to reap the benefits of better muscle protection and more efficient oxygen transportation.

Scientists have determined that at high altitudes of 2,400 meters plus, we inhale approximately three quarters of the amount of oxygen molecules that we would at sea level.  This decreases as you go higher.  As a reference, on the summit of Mount Everest (8,848m above sea level) we inhale only a third of the amount of oxygen we would at sea level, which is not enough to sustain human life. 

Altitude Training at the AIS

To simulate this low atmospheric pressure, enabling athletes to get the benefits of altitude training without having to travel to high altitude areas, scientists at the Australian Institute of Sport have developed an ‘altitude house’.

This house, comprised of 12 beds, bathroom, kitchen and a lounge, simulates what it would be like to live at high altitude.  The AIS recreate the low pressure atmosphere of 2500 metres by changing the composition of the air within the house to approximately 85% nitrogen and 15% oxygen. The air is not thinner, but the presence of less oxygen is physiologically equivalent to being at altitude.

Athletes from endurance sports like cycling, rowing, race walking and swimming live in the house for 3-4 weeks at a time, a couple of times a year.  At the same time, they maintain their standard training regime in the normal atmosphere in Canberra, which is 600 metres above sea level.

According to Professor Gore, this ‘live high, train low’ program enables athletes to reap the benefits of high altitude living, while still enabling them to train with the same intensity and frequency.

“Australia is at a disadvantage to other countries because we don’t really have big mountains for our athletes to live or train on, so the altitude house allows us to simulate what other countries have already,” Professor Gore said.

“And this way we get similar benefits from the altitude house that we would get from natural altitude by flying the athletes to train in say Europe, but without having to sacrifice their access to their physios, doctors, nutritionists, friends and family.”

Some athletes use the house as preparation for events where they will be competing at high altitudes.  Mainly however, coaches are using the ‘altitude’ house as a way to improve performance at sea-level events.

“By living in the house for 12 hours or so a day, the athlete’s red blood cell counts increase, their haemoglobin increases. As well, their muscle buffering capacity, ability to handle lactic acid and their efficiency also improves. They can then use these factors to their advantage in training and competitions.

“Overall, we’re talking about a 1-2% increase in performance, which mightn’t sound like much, but can be the difference between a medal and failing to qualify,” Professor Gore said.

But the effects don’t last forever.  For example, Professor Gore quotes a study where Kenyan runners who lived and trained in high altitude all their lives were taken to a low-altitude region of Germany to train.  After 6 weeks they runners had lost 5% of their haemoglobin showing a relatively fast de-adaptation[i].

“The verdict is still out, but we’re looking at benefits lasting for between 2-4 weeks for sea level athletes who return to normal sea level training.”

For Professor Gore, one of the most interesting things about altitude is its ability to both hinder and help athletes, depending on their event.

“In cycling for example, the thin air means there is less drag, and in short stints in particular, athletes’ ability to absorb oxygen is not badly affected.  This is true of almost all explosive events, including sprints, long jump and triple jump.

“But for endurance events, like the ones our altitude training athletes compete in, kayaking, rowing and race walking, they are hit hard by the lack of oxygen and the lack of air resistance means little,” Professor Gore concluded.

Professor Chris Gore in the Altitude House at the Australian Institute of Sport

[i] N. Prommer, S. Thoma, L. Quecke, T. Gutekunst, C. Volzke, N. Wachsmuth, A. M. Niess, and W. Schmidt. Total hemoglobin mass and blood volume of elite Kenyan runners. Med.Sci.Sports Exerc. 42 (4):791-797, 2010.

By altering water temperature or current in a pool, bath or shower, the human body responds in a variety of ways – including fluctuations in core temperature, heart rate and metabolism and the widening (dilation) or constriction of blood vessels.

This use of water to improve body recovery is known as hydrotherapy and is becoming one of the most widely used practices in elite sport. Here, we find out how it works.

Dr Jo Vaile is only 28 years old but has already established a strong career as a Senior Recovery Physiologist for the Australian Institute of Sport (AIS). She uses a wide range of recovery techniques with AIS athletes such as hydrotherapy, compression and stretching to help elite Australian athletes perform the best their bodies are capable of.

Dr Jo Vaile of the AIS

“Exercise physiology is about understanding the complexities of how the body responds and adapts to the stress of exercise and how we can push the human body to new limits to enhance the likelihood of success,” Dr Vaile said.

“In sport, we constantly need to be ahead of the competition in order to succeed at an elite level where that one percent advantage over the opposition will make a difference between gold and silver,” she said.

In her day to day job, Dr Vaile individually assesses athlete’s physiological recovery requirements to ensure they can compete and train at their best one hundred per cent of the time.

“I love the challenge of creating a gold medal environment for each of the athletes I work with, while assessing and monitoring the body’s response to exercise to maximise their performance,” she said.

She is also responsible for conducting research, mainly into the effective use of hydrotherapy, explained below.

The human body responds to water immersion with changes in heart rate, blood pressure and blood flow.

Exposure to cold water causes a decrease in core body and tissue temperature which results in a reduction in blood flow to the extremities (muscles, hands, feet) because the body is trying to protect itself and conserve ‘body heat’.  To minimise the blood returning to the extremities the blood vessels constrict, heart rate slows down and blood pressure increases due to the constricted blood vessels.

At the AIS, athletes use cold water immersion in pools between 10-15 degrees Celsius, using the cold water to help decrease muscle inflammation, spasm and pain.

The 'ice-bath', normally kept at 10 degrees Celcius

In warm water, the body is exposed to heat which causes dilation of the blood vessels near the surface of the skin. The core body temperature starts increases and redirects more blood to the extremities. The dilation of blood vessels lowers blood pressure by allowing the blood to flow more freely with less resistance.

At the AIS however, hot water is rarely used on its own. In fact, one of the most effective athlete recovery systems to date is alternating immersion in hot and cold water.

According to Dr Vaile, ‘contrast water therapy’ can reduce swelling and muscle pain through a pumping action which is created by alternating blood vessel constriction and dilation. The pumping action helps to flush out waste products from the muscles that build up during exercise, such as lactic acid and minimises muscle tear.

“Contrast water therapy may bring about changes to tissue temperature, blood flow, blood flow distribution, may reduce muscle spasm, hyperaemia of superficial blood vessels and inflammation, as well as improving the range of motion and flexibility,” she said.

The hot-cold walk through showers of the AIS

In one recent study of twelve elite male cyclists, the athletes were put through rigorous training with the only difference being their recovery strategy. Over five days, the athletes completed four experimental trials differing only in recovery intervention: cold water immersion, hot water immersion, contrast water therapy, or passive recovery.

The study found that both sprint and time trial performance were enhanced when athletes utilised both cold water immersion and contrast water therapy, in comparison to hot water immersion and passive recovery. 

“Overall, the study found that cold water immersion and contrast water therapy improved recovery from high-intensity cycling when compared to hot water immersion and passive recovery, with athletes better able to maintain performance across a five-day period,” Dr Vaile said.

Dr Vaile is fascinated by hydrotherapy and after completing her Bachelor of Sport and Exercise Science, and went on to complete her PhD in the area.

“So many athletes implement hydrotherapy for recovery in the hope of assisting the recovery of muscle damage or fatigue and I think its fascinating that hydrotherapy has the potential to be beneficial, not only in terms of recovery, but also in improving  subsequent performance,” she said,

Dr Vaile is currently in the UK with the Rollers and Gliders – the Australian Men’s and Women’s wheelchair basketball team who are competing in the World Championships.

“Paralympic athletes are truly elite, they train and compete like any other athlete, but on top of that they face challenges every day in both sport and life due to their specific disability.”

Dr Vaile’s research into hydrotherapy earned her the European College of Sports Science Young Investigator Award and the John Sutton Best New Investigator Award at the Sports Medicine Australia Conference.