It seems like a no-brainer. An electric fan will cool you off in a heat wave, right? But researchers in England say there's no hard evidence that fans are effective—or safe—ways to beat the heat.

The UK researchers report they were hoping to craft guidelines on fan use during heat waves and at massive public events such as the 2012 Olympic summer games which start in London on July 27.

But as reported in the Cochrane Library, an online database "of high-quality, independent evidence to inform healthcare decision-making," clinical research has produced a mixed bag. Dr. Saurabh Gupta wrote in the group's report:

Some [medical research studies] suggested that fans might reduce health problems, while others suggested that the fans might make things worse.

Of particular concern: Some studies suggest that in some instances, fans may contribute to heat gain. If people feel hotter, they may perspire or sweat more, which may lead to dehydration or other health problems.

Another of the report's researchers, Katie Carmichael of the UK's Health Protection Agency, said the group's report doesn't "support or refute the use of electric fans during a heat wave and people making decisions about them should consider the current state of the evidence base."

Consumer Reports' experts have offered several cooling tips and safety advice for hot weather, including:

• Take cool baths or showers if possible. (See Stay-cool tips for hot days and nights.)
• Drink plenty of liquids, but avoid caffeinated and alcoholic beverages (See: Keep your cool, avoid heat-related illnesses)
• Air conditioners can effectively cool a room or a home—if the model is appropriate for the room (See Air conditioners that keep you and your wallet cool)
• All of the room air conditioners recently tested by Consumer Reports did an excellent job at cooling. (See The best air conditioning for the hot summer ahead and Consumer Reports Air conditioner Ratings,)
• Thermostats should be set to cool a home only when it is or about to be occupied. Many of the newer thermostats tested by Consumer Reports experts can be programmed for various times and days of the week, (See Use a programmable thermostat to keep cooling costs in check)

What are your tips for keeping cool this summer?

Sources:
Health Protection and Heatwaves: The Need for Systematic Reviews [The Cochrane Library]
Electric fans for reducing adverse health impacts in heatwaves (absract) [The Cochrane Library]
The Cochrane Library Podcast (5-minute audio file opens in new browser window)
Cochrane finds no reliable evidence on effectiveness of electric fans in heatwaves [Medical Express News]