Heart ache ... there's a biological basis when old married couples die within a few days of each other.

Heartaches ... there's a biological reason why old married couples sometimes die within a few days of each other.

IT REALLY is possible to die of a ''broken heart'', according to research that has revealed how bereavement can weaken the body's ability to fight infections.

Scientists found the emotional stress of losing a loved one could lead to parts of the immune system being suppressed, leaving grieving relatives more vulnerable to infections from bacteria. The findings could help explain cases of widows and widowers who die soon after their spouse.

Lord Callaghan, the former British prime minister, died of pneumonia aged 92 in 2005, just 11 days after Audrey, his wife of 67 years.

Johnny Cash died of complications related to diabetes while in hospital in 2003 at the age of 71. It was said at the time that he had been left weakened by the grief of losing his wife June, 73, three months earlier.

Immunologists at the University of Birmingham found increased stress levels and depression brought on by grief could interfere with the function of a type of white blood cell known as neutrophils, which are responsible for fighting bacterial infections such as pneumonia.

The impact became more profound in older adults because they had lost the ability to produce a hormone to counteract this dampening affect, meaning even healthy elderly people could fall victim to disease.

Janet Lord, who led the research, said: ''There are a lot of anecdotes about couples who were married for 40 years when one of them passes away and then the other dies a few days later. It seems there is a biological basis for this. Rather than dying of a broken heart, however, they are dying of a broken immune system. They usually get infections.''

The researchers studied the immune systems and hormone levels of 48 healthy adults aged 65 and over. Half of the group had suffered a major bereavement in the past year. They found the antibacterial action of neutrophils in grieving participants was significantly reduced compared with those who had not suffered a bereavement. The bereaved also had raised levels of the stress hormone cortisol.

The researchers also found that suffering a hip fracture could lead to the same hormone imbalance. This could explain why about a quarter of people over 80 die within a year of suffering a hip fracture.

The Telegraph, London