Ask someone to name illnesses or conditions resulting from exposure to heat and most people seem to be able to mention one or more of the classic five:
- prickly heat
- heat cramps
- fainting (also known as syncope to a few)
- heat exhaustion, and
- heat stroke.
But ask them to then go on and list any chronic illness associated with long term exposure to heat and you will probably get “err, I think I heard kidney stones somewhere…..”
Is this because there are none or are we just less informed? It’s more like the latter. They do exist but often there is less information available on the conditions and/or the data is sometimes inconclusive. There has been some evidence on the increased incidence of kidney stones related to occupations in hot environments such as steel & glass, which are pretty convincing (Borghi et al 1993, Atan et al 2005). Also a study which looked at heat waves in Adelaide (Hansen et al 2008) picked up an increase in hospital admission rates for kidney complaints for men between 35 to 64 years old.
Other studies have suggested that long term heat exposure can impact on the liver, heart, digestive system, skin conditions and the central nervous system. There are also concerns relating to both sexes when it comes to reproductive process. For the men it is a case of lower sperm counts or temporary infertility associated with the elevated core temperatures. For the ladies, there may be an increased risk to the unborn foetus during the first trimester if the mother’s core temperature gets higher than 39C for extended periods.
More recently there are increasing concerns relating to the rising incidence of kidney disease in South American agricultural workers. This is thought to be associated with recurrent dehydration combined with the intake of high levels of fluids containing certain sugars. This may potentially result in a kidney injury via a fructokinase- dependent mechanism (Jimenez et al 2014).
It doesn’t matter how you look at it the evidence seems to be there. Not only do we need to be careful and watch out for the short term issues but also the potential for something to go wrong in the long term. As they say in the classics, if you have any concerns in this area you should discuss it with your medical practitioner or (if you’re lucky enough to have access to one) an occupational physician.
There is enough evidence in the literature to indicate that apart from the acute illnesses we are already familiar with, heat can also have long term impacts on your health.
Borghi, L, Meshi, T, Amato, F, et al (1993). Hot Occupation and Nephrolithiasis. J Urology, 150: pp 1757-1760.
Atan, L., Andreoni, C, Ortiz, V, et al (2005). High kidney stone risk in men working in steel industry at hot temperatures. Urology, 65: pp 858-861.
Dukes-Dobos, FN (1981). Hazards of heat exposure: A review. Scand J Work Environ Health, 7: pp 73-83.
Jimenez, C.A.R., Ishimoto, T., Lanaspa, M.A., et al. (2014). Fructokinase activity mediates dehydration-induced renal injury. Kidney Internatinal. 86, 294-302
If you know of other good papers or references on this topic please let me know.