Unless things are super hot and dry, a powered wind does blow some good.
Your BP scribbler is married to a fan fan.
When the mercury rockets higher in the summer months, the go-to option for night-time bedroom comfort is one of those mysterious and expensive Dyson gizmos that has no visible fan-blades and yet produces a blast of air strong enough to blow the toupee off Elton John.
Your ageing scribe, however, can’t see the point. “You’re just shovelling a load of hot air from yonder to hither, but not actually cooling things down”, he’s been heard to opine. The usual response to this observation is a belligerent cranking up of the power setting from “Gale Force 5” to “Here Comes Cyclone Tracy”.
So who is right?
According to an analysis by Australian and Canadian researchers, it turns out we are both correct, sort of. It just depends how hot and how dry the conditions actually are.
Publishing this week in JAMA Network Open, a team of boffins took a deep dive into measuring how temperature and humidity impacted on the effectiveness of a fan or wetting the skin for reducing body temperature and comfort levels.
To achieve this, they subjected a group of nearly 60 older folks – some with coronary artery disease and some without – to a range of three-hour long heat exposures. These included “hot and humid” (38°C and 60% humidity) and “very hot and dry” (45°C and 15% humidity).
For the hot and humid test, all participants (with a mean age of 68 years) underwent four exposures separated by 72 hours or more, in randomised sequence: control, fan use, skin wetting, and fan use with skin wetting.
In very hot and dry heat, participants with CAD only underwent control and skin wetting exposures.
What the researchers found was that fan use did “marginally” improve body temperature in conditions of 38°C heat with 60% humidity. Conversely, however, when study groups were tested in 45°C of dry heat, using a fan raised their body temperatures and sweating and made them feel more uncomfortable.
“In very hot and dry heat, fan use worsened all outcomes and should be discouraged for these conditions,” the researchers said.
However, “skin wetting” was shown to reduce sweating and “improved perceptions in both heat conditions and could be recommended to minimise dehydration risk”.
Interestingly, the mildly positive finding for fan use in hot and humid conditions runs contrary to advice from the US Centers for Disease Control and Prevention, which cautions against fan use above 32°C because of what it says is the threat of increasing one’s body temperature.
The researchers point out that their study results are limited by the “short, laboratory-based exposures” and say replication of these tests in other heat-vulnerable populations should be considered.
And those of us living in already warm and wet climates would concur.
Given the twin threats of soaring power prices and global warming trends, we welcome some more definitive research into the issue – if only for the sake of marital harmony.
Blow our socks off by sending story tips to Holly@medicalrepublic.com.au.
