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.