As my year of showering variously comes to a close I am pondering two important questions.

  1. Should I continue for another year due to the clamour from my fans?
  2. Are long hot showers actually bad for you?

The latter question arose from a Defra “messaging event” (presumably from the same stable as “blue sky thinking” and “pushing the envelope”) where it was suggested that this statement would be a good slogan to encourage the public to take shorter showers if it was pronounced as follows: “Doctors say that long hot showers are bad for your health”.

Even if it is true, I am not convinced such a message would result in a step change in behaviour. As a species we carry out many activities that are harmful for our health including smoking (despite many years of increasingly blunt messages about how we are killing ourselves every time we light up), and if the Government is going to put money into an advertising campaign and doesn’t want to talk about the environmental advantages of shorter showers (though why not is beyond me) then the “adherence to social norms” way of encouraging behaviour change seems to be a far better use of limited funds.

Anyway, pondering this question led me into the “dangers of everything” world that you can find so easily on the web. An article from the Taiwan News that said exposure to trihalomethanes (a by-product of chlorine disinfection that can lead to an increased risk of cancer) is increased under a hot shower as they become volatile when heated, and that you should ventilate bathrooms to reduce this risk. It is true that trihalomethanes are carcinogenic but my understanding was that there needs to be organic matter in the water supply, with which the chlorine reacts, to cause the formation of this chemical in the first place. Which there isn’t in mains water. Plus, the scientist quoted in the report used lots of words like, ”may” and “possibly” and “over 20 minutes”.

Mostly, the disadvantage of hot showers is that the skin dries out more quickly as the natural oils in your skin melt faster due to the heat, and so are more easily removed when you soap up. There is far more information about the health benefits of hot showers: the warmth stimulates circulation and blood flow; loosens joints, tendons, tissues and muscles; eases pain, stimulates healing and reduces inflammation. Some websites recommend hot showers to cure insomnia (while others state that cold showers do the same thing!), and there is a school of thought that hot showers increase the production of heat stress proteins. But overall (in my research of headline articles) there does not seem to be any scientific evidence that long hot showers are bad for your health.

So we can put question two to bed and address question one, the answer to which is “What clamour?” But maybe I will…

December 2012 – Are hot showers bad for you?