In a monastery in northern India, Tibetan monks sat quietly in a room, deep in meditation. Although the room was a chilly 39 F, the men - using a yoga technique known as Tum-mo - were scarcely clothed, but seemed unaffected by the cold. Nearby, other monks soaked large sheets in freezing cold water and placed them on the shoulders of the meditators. Within an hour, the sheets were dry.

Scientists who have studied the monks - some of whom were capable of raising the temperature of their fingers and toes by 17 F - have yet to determine how the meditative process was able to generate so much heat. But they agree about one thing - the mind can manipulate the body in to doing quite unexpected things. Can we train it to better control our bodies when they are cold, injured or under stress?

Herbert Benson, an associate professor of medicine at Harvard Medical School and president of the Mind/Body Medical Institute in Boston believes so. He has developed a "relaxation response" which he describes as "a physiological opposite to stress". It can produce changes in metabolism; breathing rate, heart rate and thermoregulation, and Benson's team have used it to treat anxiety, depression, high blood pressure, heartbeat irregularities, excessive anger, insomnia and even fertility problems. "I want to investigate what advanced forms of meditation can do to help the mind control physical processes once thought to be uncontrollable", he says.

The human brain, which is made up of three parts - the fore, mid and hind brain - controls our actions via the central nervous system. The mid and hind brain unconsciously regulate autonomic processes related to essential body functions such as respiration, heart rate and digestions and the forebrain controls cognitive and conscious functions such as memory, language and motor function. When you decide to lift a pencil, your conscious brain makes hundreds of decisions that result in an instruction to your hand. If we can make the unconscious and the conscious brains better in tune with each another perhaps, we can encourage our bodies to alter previously automatic responses.

Studies in which breast cancer sufferers used guided imagery techniques to ‘imagine’ themselves better, showed that positive thinking encourages the body's white blood cells to fight the cancer cells more effectively. "One of the major contributors to maintaining health and removing disease is the attitude of the patient ", says Professor Oakley Ray, a psychologist from Vanterbilt University in Tennessee. "Words can have the same effect as drugs".

Although, the benefits of a positive attitude are still contested in cancer treatment, one area where the healing properties of positive expectation are widely accepted is the use of placebos in drug trials. Volunteers react physically to substances that contain nothing, as if they contained the actual drug. As the Canadian neuroscientist and placebo expert Mario Beauregard observes, "The psychophysiological responses elicited by placebos seem to suggest a mind/body interaction that is guided by subjective factors, such as expectation, beliefs, meaning and hope for improvement". The effect is very specific and depends on the information given to the recipient. For example, a placebo will have the opposite effect on heart rhythm and blood pressure when it is given as an inhibitor than when it is administered as a stimulant.

Baroness Susan Greenfield, one of Britain's leading neuroscientists believes the NHS, for example for Parkinson ’s disease, could better harness the placebo effect where it has already been shown to be just as effective as medicinal drugs: "The central nervous system and the immune system are closely linked. It is quite amazing that if I whisper in your ear "You've passed the exam" that triggers changes in your heart rate and blood pressure. Tapping into something cognitive, which is predicated on the values of higher expectations, has very real physical consequences."

So can we implement this mind over matter approach in our daily lives? Fortunately, it does not require years dedicated to a technique such as Tum-mo - simpler techniques can retrain the brain and body just as effectively. Scientists have found that in people who are depressed, angry or stressed, the right frontal cortex of the brain is more active that the left. Over time, brains develop what is known as a ‘set point’. If a person's set point is tilted to the left then the tendency is for lots of activity in the left frontal cortex, making for a happy person. If it is tilted to the right the opposite occurs. But the set point can change: volunteers who undertook a short course of Buddhist-style meditation moved their set point to the left. They also developed remarkably superior responses to influenza.

And it can work the other way round. Neurolinguistic programming – altering your behavioural patterns to retrain your brain - is advocated by some, the hypnotist Paul McKenna, for example, as a way of beating depression and addiction. By repeating mantras to yourself, or practicing conscious repetitive actions such as tapping each time you think about the relevant topic, you can manipulate your mind.

So, unless your goal is to become a human radiator, you can retrain your brain to be happier – and your body to be healthier – without too much difficulty. "The brain is the source of everything we do", says Lady Greenfield. "And it is a creature of habit. You can change your habits."

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