I thought my trouble sleeping, racing heart and constant sweating were all signs of my anxious personality. In fact, they were symptoms of a serious disease that’s overlooked. These are the tests you MUST ask your doctor for if you’re suffering like me

For years, Harry Thorn thought his sleepless nights, constant sweating and anxiety were just part of who he was.

‘I would lie awake for hours with my heart thumping in my chest, struggling to get to sleep,’ says Harry, 27, a fat-loss coach who lives with his girlfriend Ellie Trew, 27.

‘I also always felt on edge, but decided that was just my personality.’

He was also ‘hot all the time – so sweaty that at dinner parties or other social events I’d feel very self-conscious’.

In fact, he had an overactive thyroid gland. Yet Harry might have continued to be in the dark about it had it not been for a fitness test he took as part of his sports and exercise degree at university.

For the test, he had to cycle in a lab while wired up to a heartrate monitor.

‘Mine was flashing 110 beats per minute before we’d even started cycling,’ says Harry, from Guildford, Surrey.

The normal range for most healthy adults is 55 to 85 beats per minute.

Harry’s was so high his teacher came to check if the monitor was broken.

‘When he realised it wasn’t, he looked shocked and told me to go to the doctors,’ he says.

At his GP surgery, they found his resting heart rate was so high that they were concerned about the strain it was putting on his heart.

Weeks of tests – including blood pressure checks and an electrocardiogram to monitor the health of his heart – brought no answers about the cause.

‘It was as a last resort, after about five appointments, that the doctor said, “well, there is one last thing we could test you for – a thyroid problem – but it’s much more common in women”,’ recalls Harry.

Sure enough, two weeks later, results of a blood test revealed Harry had hyperthyroidism, also known as an overactive thyroid.

The condition develops when the thyroid gland in the neck produces too much thyroid hormone, which regulates numerous processes in the body from heart rate to metabolism. An excess of it causes multiple other processes to speed up.

Symptoms can include a racing heart, excessive sweating, heat intolerance, anxiety, tremor, diarrhoea, insomnia and unexplained weight loss.

Because of their general nature, the symptoms can get mistaken for stress, anxiety, overwork or simply having a naturally energetic personality, says Dr Saira Hameed, a consultant endocrinologist at Imperial College Healthcare NHS Trust in London.

‘One of my patients felt so unwell with a racing heart, heat intolerance and insomnia that she went to A&E and was diagnosed with anxiety,’ she says. ‘It highlights the need to be a bit of a detective when diagnosing hormone-related illnesses.’

A red flag, she says, is if someone has ‘heat intolerance that can’t be explained by a mood disorder’.

‘That should prompt doctors to consider an overactive thyroid.’

In fact, while hyperthyroidism affects around 1 per cent of women, it affects only 0.1 per cent of men. (And hypothyroidism – the opposite problem where the body doesn’t produce enough thyroid hormone – affects around eight times more women than men.)

Harry’s overactive thyroid was caused by Graves’ disease, the most common cause of hyperthyroidism which occurs when the immune system mistakenly attacks the thyroid gland, causing it to produce excessive amounts of the hormone.

‘Autoimmune conditions, including those affecting the thyroid, are much more common in women than men,’ says Dr Hameed, who is also the author of Signals: The Inside Story of Our Hormones.

‘We don’t fully understand why, but it’s thought that female hormones such as oestrogen may make the immune system more active, while testosterone may have a protective effect.’

In theory, thyroid problems should be easier to spot in men than women, says Lyn Mynott, the founder and chief executive of the charity Thyroid UK.

‘Symptoms of hyperthyroidism such as sweating, feeling unusually hot and tiredness can be put down to the menopause in women rather than a thyroid problem,’ she says.

The challenge is that men – as was the case with Harry – sometimes delay seeking help for their symptoms.

‘Once men do seek medical advice, hyperthyroidism can sometimes be picked up more quickly because the symptoms are often easier to recognise, such as excessive sweating, feeling unusually hot, trembling, anxiety and diarrhoea,’ she adds.

And yet it’s important they do seek help because without treatment, an overactive thyroid can lead to serious complications.

‘These include severe mood disturbances, including mania; heart-rhythm problems such as atrial fibrillation; weakening of the bones leading to osteoporosis; and strain on the heart that can eventually result in heart failure,’ says Dr Hameed.

Looking back Harry says he now realises he had ‘probably been dealing with symptoms for years’.

‘During a session at the gym I had to sit down and actively calm myself down, taking deep breaths, because my heart felt painful due to palpitations.’

And he found himself constantly boiling hot, sweaty and uncomfortable. What’s more, he was always hungry.

‘I had an increased appetite which I was taking advantage of to try and gain muscle,’ he says. ‘I could eat four meals every evening – no problem – and was probably consuming 6,000 calories a day.

‘I’d convinced myself the symptoms were just who I was. I never considered there could be a medical reason behind it.’

Following his diagnosis, doctors explained that while Graves’ disease is a lifelong condition, the symptoms of an overactive thyroid can usually be controlled with treatment.

Harry was prescribed carbimazole, a medication to reduce the amount of thyroid hormone his body was producing.

He says: ‘I was told to take higher doses until my thyroid hormone levels started to come down.

‘After a month or two, my dose had increased to 45-50mg – higher than the 30-40mg generally prescribed for moderate to severe hyperthyroidism – but my body didn’t tolerate it well and I became dangerously dehydrated.

‘The doctor explained that high doses can sometimes put stress on the liver and kidneys. Luckily, the medication had already started lowering my thyroid hormone levels, so I was gradually moved on to lower doses.’

Dr Hameed explains: ‘Graves’ disease can wax and wane. In some people, the overactive thyroid lasts for around 12 to 18 months before entering a period of spontaneous remission, when thyroid hormone levels return to normal. However, this is often followed by a relapse.’

Not all cases respond to medication, and some may need treatment with radiotherapy or surgery to reduce the amount of thyroid hormones the thyroid gland produces.

Harry is now on a low maintenance dose of carbimazole.

‘I take 5mg once a week, sometimes every two weeks. I’ve tried coming off it before, but the flare-ups come back.

‘I also get symptoms if I consume too much high calorie or fatty foods, like sugary doughnuts. That will almost always guarantee a flare-up. I’m much more aware of my triggers now.’

Dr Hameed says there is no prescribed diet for those with hyperthyroidism.

‘If someone has a very fast heart rate or shaky hands, it’s sensible not to drink too much caffeine as this can make those symptoms worse,’ she says.

‘Once thyroid hormone levels are under control, there’s no need to follow any specific diet.

‘However, Harry clearly knows his own body and has found certain foods don’t agree with him, so he’s sensibly avoiding them.’

Harry says his medication has made a huge difference.

‘I’m no longer tired and wired all the time, and my concentration and focus are also a lot better. I know my triggers and I’ve got my nutrition sorted.

‘I think men can be guilty of brushing things off when it comes to their health, but if you’re constantly feeling on edge, overheating or experiencing a racing heart, it’s worth speaking to your doctor.’

Dr Hameed agrees, saying: ‘Men, don’t leave things or try to explain them away. Speak to your doctor and ask about thyroid blood tests. They are quick and easy to arrange and will identify thyroid disease if it is the cause of your symptoms.

‘We have very good treatments but it’s important we make the diagnosis as soon as possible.’