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Sometimes life just isn't fair - especially for older women. They are much more likely than men to lose muscle mass as they age, a new study suggests.

And without strong muscles, particularly in the legs and hips, women are at greater risk of suffering from a debilitating fall which could land them in hospital with a broken bone - or worse. "If a woman over the age of 65 has a fall, she has a 50-per-cent chance of being dead in two years and that is a frightening statistic," said one of the researchers, Michael Rennie of the University of Nottingham in Britain.

The study, which was done in collaboration with researchers at Washington University in St. Louis, Mo., is based on an assessment of 29 healthy men and women aged 65 to 80.

The findings indicate it is more difficult for women to replace muscle that is lost naturally as they grow older because of key changes in the way their bodies process food.

"Postmenopausal women were less able to respond to food to build muscle mass, whereas men of the same age were able to store protein in muscle," the researchers said in a statement released with their study, published in the online journal Public Library of Science One.

To make matters worse, women tend to have less muscle and more fat than men in middle age. "So they are nearer to the 'danger' threshold of becoming frail when they reach their 50s and 60s," the researchers report.

Until more research is done, Dr. Rennie can't say why women lose their ability to efficiently convert dietary protein into muscle. But he suspects hormonal changes during menopause are largely to blame for putting women at a "disadvantage" compared with men.

Even so, it's not completely hopeless for women. They can compensate by eating a higher proportion of protein-rich foods - eggs, fish, chicken and lean red meat - and doing more resistance exercises such as lifting weights, Dr. Rennie said. "This should help reduce the loss of muscle over time."

And to prevent weigh gain, he suggests cutting back on fatty foods so total calories remain the same. "You should be replacing the fat with protein," he said.

Sleep and the heart

A new study provides an ominous wake-up call for shift workers, flight crews and those who frequently have trouble sleeping. It indicates that chronic sleep disruptions could trigger heart disease and possibly harm other vital organs.

The results are based on lab experiments involving hamsters, but the lead researcher, Michael Sole of the Peter Munk Cardiac Centre at the Toronto General Hospital, says there's good reason to believe the findings apply to people, too.

The researchers found that when the hamsters' circadian rhythm - or internal biological clock - got out of sync with external cues (such as the day-night cycle), the animals developed clear signs of heart disease.

What's more, there was also evidence of kidney damage, according to the study published in the American Journal of Physiology - Regulatory, Integrative and Comparative Physiology.

Dr. Sole noted that other studies have suggested the heart goes through a daily period of rest and restoration which normally occurs at night - and this process is tightly regulated by circadian rhythm.

If the body's internal clock is constantly disrupted - such as through frequent changes in shift-work schedules - the heart may not get the regenerative rest that it needs to keep functioning properly.

Dr. Sole urged shift workers to consider these finding when they are scheduling their work time. And, if possible, they should try to maintain a constant work schedule for one month or more at a time, allowing the body sufficient time to readjust its internal clock, he said.

Drug costs levelling

The skyrocketing cost of prescription drugs appears to be levelling off - at least a little bit, according to report by IMS Health Canada, a private company that tracks medication sales.

In 2007, the total bill for prescription drugs sold through pharmacies and dispensed in hospitals rose 6.3 per cent to $19-billion.

In recent years, drug costs have been climbing at a faster clip - averaging 8.4 per cent annually from 2002 and 2006.

So what's the major reason for the slowdown? Patents have recently expired on several top-selling, brand name drugs, allowing them to be displaced by cheaper generic medications, explained Ian Therriault, senior vice-president of IMS.

"The dollar value of brand products losing patents last year was at an all-time high of $1.2-billion," he said. Two drugs alone - Altace (a blood pressure medication) and Effexor XR (an antidepressant) - account for 60 per cent of this figure.

Mr. Therriault expects the current trend will continue for a while because more brand-name drugs are about to lose their patent protection.

When learning hurts

It is possible to improve your sense of smell but the learning process can be painful, new research shows.

For the study, volunteers were exposed to a pair of smells that were nearly identical in their chemical makeup.

At first, the volunteers found it virtually impossible to distinguish between the two. Then they were exposed to the smells again - only this time they got a mild electric shock with one of the smells but not the other.

After repeating the painful procedure several more times, the subjects became much better at telling the difference between the two smells.

The researchers, writing in today's edition of the journal Science, conclude that emotions - such as fear of pain - can heighten our senses and help us avoid danger.

"It's evolutionary," the lead research, Wen Li at Northwestern University in Chicago, said in a statement released with the study.

"This helps us to have a very sensitive ability to detect something that is important to our survival from an ocean of environmental information. It warns us that it's dangerous and we have to pay attention to it."

ptaylor@globeandmail.com