During troubled times, remedies are needed to help us adapt to stress, improve performance and increase our resistance to disease.

Eighty per cent of illness is caused by stress and none of us can escape from it entirely, despite searching for ways to minimise its effects and pursuing rest, recreation and regular exercise.

Meanwhile, we look to coffee and chocolate biscuits to keep us going, unaware that these will stress us internally even more.

The arctic herb Rhodiola rosea, also known as golden root, has been used for thousands of years by people living in extreme conditions.

The Vikings took it on long journeys to promote stamina and resistance. Descendants of Genghis Khan, the ancient Siberians, knew where the plant grew wild in the Caucassus mountains and used its extracts to prevent sickness and treat serious disease, passing their knowledge down through generations.

The medicinal properties of this plant are such that the Soviet authorities kept the information to themselves.

Russian scientists developed products containing Rhodiola to improve the performance of their soldiers, cosmonauts and Olympic athletes.

Only since the end of the Cold War have Rhodiola's huge range of health benefits come to light in the West.

Rhodiola rosea is known as an adaptogenic herb. Adaptogens are "stress-busters", helping the body to restore balance and adapt to stressful physical or psychological circumstances without any toxic side-effects.

Not many plants can fulfil these criteria, but Rhodiola contains a variety of highly active components, such as the phytochemicals rosavin and salidroside.

Experiments have shown that taking extracts of this herb may help to increase stamina and accelerate the body's recovery process after exercise. Many people also experience an increase in energy and immunity.

Rhodiola protects heart tissue by decreasing the amount of corticosteroids released during the stress response and helps the body to regulate cholesterol, blood sugar and blood pressure (anyone on prescribed medication should always check with their doctor before taking herbs).

Dr Israel Brekhman, who pioneered the work into adaptogenic herbs, believed Nature to be "the greatest laboratory on Earth."

One of the most exciting areas of current research focuses on Rhodiola rosea as an effective anti-depressant.

It is thought that even slight imbalances of the neurotransmitters may affect mood or behaviour, and many drugs work by increasing levels of serotonin.

In clinical studies, Rhodiola rosea significantly decreased symptoms of depression by enhancing the uptake of serotonin into the brain and helping to preserve it.

There are many reports of herb also improving memory and mental function.

A reliable source is Solgar's Rhodiola Root Extract, available from health-food stores (60 caps for £14.99)

There are no miracle cures to protect us from adversity. Yet we are fortunate that, along with other strategies for survival, natural agents do exist which help prevent ill-health due to severe or prolonged stress.