A sauna can relieve cold symptoms.
Scientists recently confirmed the age-old notion that hot liquids can relieve some cold and flu symptoms. But what about a dose of heat on a much larger scale—say, in a sauna?
With temperatures of 80 degrees celsius or more, saunas have been recommended for arthritis, asthma and chronic fatigue, among other things, since they were used by nomads in Finland centuries ago. Some reputed benefits have not been examined but there is evidence that saunas may speed recovery from colds and reduce their occurrence.
Some researchers suspect sauna heat reduces symptoms because it improves drainage, while others speculate that the high temperatures help weaken cold and flu viruses. Why this might prevent sickness in the first place, however, is unclear. But research suggests an effect.
In one study by Austrian researchers, for example, a group of 50 adults was split into two groups and tracked for six months. One group was instructed to use saunas regularly; the other group abstained. At the end of the study, the sauna group had contracted fewer colds.
“This was found particularly during the last three months of the study period when the incidence was roughly halved compared to controls,” the scientists wrote.
Other studies have found similar results. But doctors caution that saunas can be hazardous for those with heart or circulatory problems.
The bottom line
There is evidence that sauna use might reduce or prevent symptoms of a cold.
Eye colour can have an effect on vision.
It is well known that people with lighter eyes tend to be more sensitive to light, a result of having less pigment in the iris to protect them from sunlight. That can place them at a greater risk of macular degeneration and other eye-related problems. But whether that extends to vision is not clear.
If there are any differences, they seem to be subtle. There is little or no evidence that darker eye colour means greater visual acuity but one theory holds that it does produce better reaction time.
Studies have examined this by looking at sports performance. One at the University of Louisville, US, found that dark-eyed people performed better at “reactive-type tasks”, such as hitting balls, playing defence in a football game and boxing. But people with light eyes did better at “self-paced tasks”, such as hitting a golf ball, throwing baseballs or bowling. A study of college students found that subjects with darker eyes performed better at hitting racquetballs. But other studies have challenged those findings, including one that looked at rugby players. Scientists say more study is needed.
The bottom line
There is limited evidence that eye colour can have a slight effect on vision.
Early exposure to nuts raises allergy risk.
Peanut allergy is one of the most common allergies in the US, for instance, afflicting up to 1.5 million Americans and killing about 100 people a year.
To prevent an allergy from developing, doctors have recommended that small children and nursing mothers avoid peanuts. But recent studies questioned if early exposure limited the allergy or increased the risk, perhaps explaining a rise in allergies.
The latest study, published in The Journal of Allergy and Clinical Immunology, found that early exposure might provoke tolerance. The authors examined two populations of genetically similar children, about 8,000 in all. In one group, most ate peanuts by the age of nine months; those in the other had little or no early exposure. The scientists found the unexposed children were six times as likely to develop the allergy.
Robert A. Wood, a paediatric immunology expert at Johns Hopkins, said the research was intriguing but not final and parents should be cautious. Some children may be genetically destined to be allergic. Parents should be on the lookout for infants who show allergies to other things or have a family history of allergy.
The bottom line
Early exposure to peanuts may benefit some children but it is still unclear.
©2009/The New York Times