Sweating is nature’s coolant – it comes to our rescue on hot days and sticky nights or any time we work up a head of steam. It regulates our body temperature, helps protect us from overheating and gives our skin a welcome moisture sheen in the searing sun.
But if your perspiration patterns are out of whack, it could be related to your diabetes – up to 75 per cent of people with diabetes experience sweating abnormalities, according to Dr Joe Kosterich, general practitioner and author of Dr Joe’s DIY Health.
“Like all bodily functions, there is a normal range – some people sweat more, or less, than others,” says Dr Kosterich. “The autonomic nervous system is in charge of controlling sweating, and sweating is part of the temperature regulation system. Hormones also play a role – testosterone promotes sweating, which is why men tend to sweat more than women.”
But when you have diabetes, the way you sweat – whether it’s a lot or a little – can be a sign your blood glucose or autonomic nervous system, which controls the body’s automatic cool-down response, is actually out of kilter.
Wet and wild?
Hyperhidrosis is the medical term for excessive sweating, and it’s a pretty familiar experience to most people who have had a low blood glucose episode – that is, a hypo.
“Sweating is a very common symptom of hypoglycaemia,” says Virginia Hagger, diabetes education manager for Diabetes Australia – Vic. Caused by glucose-lowering medication or insulin, a hypo onset can swiftly put you in a lather, but the symptoms subside as soon as a few jelly beans bring your levels back to normal.
But hypos are not the only cause of extreme sweatiness. It can also be a sign of autonomic neuropathy, where damage is caused to the nerves supplying the skin’s sweat glands by elevated blood glucose levels. Such symptoms should be checked out by your doctor, firstly to rule out hypoglycaemia as the problem, and secondly, if nerve damage is confirmed, to investigate whether it has also affected any other organs. Signs can include bladder and gastrointestinal issues such as vomiting, constipation or diarrhoea, postural hypotension (lightheadedness on standing), plus erectile dysfunction in men.
Many people perspire from every pore in their face, neck and scalp when they eat hot, spicy food. Known as gustatory sweating, this can also be a sign of diabetic nerve damage, explains Dr Kosterich.
“It is thought to be due to sweat glands that have lost nerve function being reconnected to nerve input, with a degree of overcompensation,” he adds.
It is an over-the-top reaction caused not by spicy food but by an impaired parasympathetic nervous system which, as well as regulating our heart rate and lung function, plays a role in promoting our digestive processes.
Dry as a bone?
At the other end of the spectrum is anhidrosis, or lack of sweating, which is often hard to diagnose because symptoms may go unnoticed until they are severe. Like abnormally heavy perspiration, this can also be a sign of autonomic neuropathy, where nerve damage skews normal cool-down responses.
“Anhidrosis can affect the whole, or parts, of the body,” says Virginia. Perspiration is a moisturiser and lack of it can lead to skin dehydration, with potentially risky consequences for people with diabetes.
“The skin on the feet may become cracked, leading to infection. Use a moisturiser and don’t go barefoot or wear open shoes,” says Virginia.
Anhidrosis blocks the body’s cooling responses, so heat-related illnesses are its most serious complication. Signs to watch for are heat cramps, weakness, nausea and a rapid heartbeat associated with heat exhaustion. This condition needs special monitoring, as it can progress rapidly into life-threatening heatstroke if your body temperature reaches 40°C or higher. Heatstroke can result in hallucinations, loss of consciousness, coma and even death.
But the main symptoms to look out for are dry skin and heat intolerance, says Virginia.
Be sweat savvy
When you’re feeling the heat, follow these smart steps.
- Stay alert for any changes in the way you sweat. See your GP if you’re concerned.
- Drink plenty of water to stay hydrated, wear sunscreen and protective clothing outdoors, moisturise (especially your feet) and stay out of the sun at peak times.
- If you suffer from autonomic neuropathy, you can reduce your risk of heat exhaustion by keeping cool and avoiding exercise during the heat of the day.