Jetlagged hamsters on Viagra The male impotence drug Viagra may be useful in treating jetlag (but only if you're heading east) and may also help ease problems associated with shift work. In studies by Universidad Nacional de Quilmes in Buenos Aires, hamsters given low doses of sildenafil (sold as Viagra) recovered from disruptions to their circadian rhythms as much as 50 per cent faster than those who weren't. Team leader Diego Golombek says sildenafil works at least as well as the natural jetlag treatment melatonin. Among other things, Viagra interferes with a molecule involved in the brain's body clock mechanism, healthday.com reports. However, it can cause side effects such as low blood pressure. Mice point the way to baldness cure American researchers have successfully grown new hair follicles in mice, pointing the way to a genetically based remedy for hair loss, as well as the treatment of wounds and other degenerative diseases. Although human and mouse skin heal differently, the University of Pennsylvania researchers say the 'unexpected findings could change our understanding of regeneration in adult mammals'. It's long been assumed that mammalian hair follicles were non-renewable, AFP reports. The researchers identified a gene that's essential for hair development, called Wnt, and were able to stimulate or stop hair growth by turning it on or off. Mouthing off about tobacco hazards Smoking is the most damaging lifestyle factor involved in worsening periodontal disease, which has been linked to serious health issues, including heart disease. Not getting enough sleep was the second worst, a four-year study by Osaka University of more than 200 factory workers has found. Researchers also examined the effects on oral health of physical exercise, alcohol use, diet, stress and working hours. Periodontal disease, which affects the teeth and gums, is thought to be caused by an imbalance of bacteria in the mouth, WebMD reports. But recent research suggests that other factors may be involved. Lest we forget about passive smokers People who have lived with a smoker for more than 30 years are about 30 per cent more likely to develop dementia than those who have never lived with a smoker. They're also at risk of heart attack or stroke or developing clots in their leg arteries, according to studies of almost 1,000 elderly people by the University of California at Berkeley, WebMD reports. Despite the link, researchers say the study doesn't prove that passive smoking causes memory disorders. Danger smoulders for abstainers Up to 100,000 Chinese die each year from diseases associated with passive smoking, with more than half a billion suffering various ill effects. Fewer than four out of 10 people surveyed by the Ministry of Health realised the dangers of passive smoking, Reuters reports, quoting the Xinhua news agency. Brainy approach to bowel problem Hypnotherapy, anti-depressants and other mind-focused treatments may help people suffering severe irritable bowel syndrome (IBS), British researchers have found - even though the disorder isn't psychological. 'In part, the symptoms are similar to those you find in depression, so things that work for depression work for it,' says Bu'Hussain Hayee, of University College Hospital in London, who co-authored a survey of previous studies and findings. IBS sufferers 'are not depressed, but the treatments work', he says. At some stage, as many as one in five adults in the US will suffer one or more symptoms of IBS, which can include cramping, bloating, constipation and diarrhoea, healthday.com reports. Cholesterol shapes up Regular exercise appears to help boost levels of so-called good cholesterol - with duration, rather than frequency or intensity, being the crucial factor. About 120 minutes a week or 900 calories burned is the minimum required to change high-density lipoprotein (HDL) cholesterol levels, according to analysis by Japanese researchers of 25 studies involving more than 1,400 people. The resulting boost in HDL levels reduces the risk of cardiovascular disease by about 5 per cent in men and 7.5 per cent in women, healthday.com reports. Coffee guards against gout Drinking four or more cups of coffee a day appears to significantly reduce the risk of developing gout, a form of inflammatory arthritis in men caused by too much uric acid in the joints. A 12-year US-Canadian study of more than 46,000 men found that those who drank six or more cups a day were 59 per cent less likely to develop gout than those who never drank coffee. The risk for men who had four to five cups a day was 40 per cent lower. Decaffeinated coffee offered less protection, but the researchers say another ingredient - such as an antioxidant called phenol chlorogenic acid - is likely to be the key, healthday.com reports. Jason Sankey is a tennis professional