Nomads in the desert…
With the relentless march of global warming the frequency of extreme heat events looks certain to increase, even if the goal of keeping global temperature increases below 2 degrees is achieved.
Working in extremely hot environments can be a debilitating experience, and has the potential to play a deadly role for your team.
Heat exhaustion and heat stroke are on a continuum of heat related illness. Heat stroke is a life-threatening emergency characterised by multiorgan dysfunction and a systemic inflammatory response. If not recognised and treated it can quickly lead to death.
Some of the processes are outlined below:
Hypotension (low blood pressure), caused by dehydration and peripheral vasodilation, can cause dizziness, light-headedness and in extreme circumstances lead to shock and collapse.
Above 40 degrees, there is potential for neural damage which can lead to neurologic dysfunction. This often presents initially as headache, dizziness, confusion, irritability or impaired judgement but can ultimately lead to severe delirium and coma.
Gastrointestinal changes are manifested clinically with increased nausea, vomiting, and diarrhoea. These can increase the loss of electrolytes which are also lost through sweating at a rate as high a 2 litres per hour. Cramping of arms, legs and the stomach is common.
Increased respiratory rates (thermal hyperpnea), which is thought to selectively reduce heat from the brain, can lead to hypocapnia and respiratory alkalosis.
In remote environments it is especially important to recognise these symptoms early, and remove the patient from the heat. Shade, rest, hydration and fanning should be priorities if other options are not available due to your situation. ‘Buddy-buddy’ systems work well for monitoring in team environments.
Glazer, J.L., 2005. Management of heatstroke and heat exhaustion. American family physician, 71(11), pp.2133-2140. ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Beker, B.M., Cervellera, C., De Vito, A. and Musso, C.G., 2018. Human Physiology in Extreme Heat and Cold. Int Arch Clin Physiol, 1(001).⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Matthews, T.K., Wilby, R.L. and Murphy, C., 2017. Communicating the deadly consequences of global warming for human heat stress. Proceedings of the National Academy of Sciences, 114(15), pp.3861-3866.