SPINAL CORD INJURY
Did you know…
…that many paralysed people cannot sweat? A
typical summer scenario. The car’s been getting hot all day in the blazing sun, you get in and next thing you know, there’s sweat pouring down you. Sweating can be a real nuisance. But it is a problem that I, for one, don’t have. I don’t sweat at all. The same is true for many paraplegics and tetraplegics because thermoregulation doesn’t work in our bodies. Why is that? To answer that question, we need to take a closer look at the autonomic nervous system (a system of two parts: the sympathetic and the parasympathetic nervous system), which controls all the processes in the body that are not voluntary, such as the heartbeat, breathing, digestion and even sweating, too. Specific sympathetic nerves that leave the spinal cord between vertabrae Th3 and L2 are responsible for sweating. Any patients with a spinal cord injury below the L2 vertebra can sweat as normal. Patients whose injury is between the Th3 and L2 vertebrae can only sweat in certain body areas. And people like me, with full paralysis above the Th3 vertebra, cannot sweat at all. You might think I’d struck lucky. But you couldn’t be more wrong. The human body requires a consistent temperature to be able to function properly. The enzymes – protein biocatalysts – which control and maintain many of our vital functions only run smoothly within a narrow temperature range. If my body temperature leaves that range, I get weak and lethargic. I suffer dizziness and it becomes hard to breathe. In extreme cases, I might even suffer heatstroke. Normally, the body will regulate its own temperature automatically. Sensors detect that the body temperature is too high and transmit that information to the autonomic nervous system. That in turn broadens the blood vessels so that warm blood can cool down on the surface. Moisture is also drawn off to produce sweat. Then, the sweat glands all over the body’s surface are activated and emit moisture onto the skin. The excess body heat transforms that sweat into vapour. The chill of evaporation takes the heat away from the body. You then sweat until your temperature comes back down to its optimal 37° C. When you can’t sweat naturally, you need to think of other ways to get your body temperature back down. I use cooling elements or wet cloths, for example, and place them around my neck or over my face. I also have a sprayer for watering plants so I can mist a film of moisture onto my skin. And I have to think ahead about whether there’s air conditioning or if I can find a shaded parking spot for the car. It’s all quite a fuss. I’d much rather have sweaty armpits.
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