Peter Forshaw was running up the pitch during a ‘lads v dads’ football match when he suddenly felt an itchy sensation across his arms – and seconds later found himself struggling to breathe.

‘I was running around when I started getting itchy on my chest and arms, which I’d never had before,’ says the married father-of-one. ‘Then my throat started itching, then swelling.’

Soon Peter, then aged 43, was on his knees gasping for air. Worried players ran over thinking it was a heart attack and one of them called 999 and paramedics rapidly arrived who rushed him to hospital.

But curiously tests rapidly ruled out a heart attack. ‘It was then the doctor saw my hives and ran some basic allergy pinprick tests,’ says Peter.

‘But they came back as negative too,’ he says.

Peter was discharged without knowing what had caused the frightening episode.

Later his wife reminded him that they had eaten breaded scampi earlier that day and they thought it might have been food poisoning.

It would be more than ten years before Peter would find out the true cause – and even then only after he had another, potentially life-threatening episode.

Peter, 68, a retired lorry mechanic from south-east London, has a form of exercise-induced allergy, known as exercise induced anaphylaxis, meaning that any exertion that raises his heart rate above resting can provoke a serious reaction.

Peter, 68, a retired lorry mechanic from southeast London, has a form of exercise-induced allergy, known as exercise induced anaphylaxis 

It means that even a brisk walk could potentially be life-threatening for him.

Anaphylaxis is a severe, potentially life-threatening allergic reaction which can be triggered by many things including foods such as nuts, an insect bite – and exercise.

The immune system overreacts and immune cells release a flood of chemicals such as histamine that can affect the entire body, ‘widening blood vessels and making them leak,’ says Dr Scott Pereira, a consultant immunologist at Medical Express Clinic, a private clinic in London.

The leaked blood and fluid causes flushing, hives and swelling; meanwhile the same chemicals tighten the airways, making it difficult to breathe.

The chemicals also ‘irritate the gut, causing pain and nausea; and if enough fluid leaks out of the circulation, blood pressure falls and the person collapses,’ says Dr Pereira.

In the case of exercise-induced anaphylaxis the reaction is provoked most often by a food but the immune system doesn’t start to overreact until someone exercises, he adds.

Most commonly it is a protein called omega-5 gliadin found in wheat which is the culprit.

‘However, shellfish, nuts, celery and tomatoes have also been implicated,’ says Dr Pereira.

‘Interestingly, many people can eat these foods without any problem when resting and can exercise safely when they haven’t eaten them.

‘It is the combination of eating the trigger food followed by exercise that causes the reaction.’

So while the immune system has antibodies to the foods in question ‘exercise is what pulls the trigger’ for the reaction says Dr Pereira.

The reason exercise provokes this reaction is that ‘it makes the gut wall temporarily more permeable, so far more of the food protein passes into the bloodstream than usually would,’ says Dr Pereira.

‘Exercise also redistributes blood flow and raises core body temperature – each of these appears to make the immune cells more unstable and readier to release their contents.’

What’s more at rest food ‘is absorbed slowly and in small amounts and stays below the threshold that would provoke a reaction.

‘During exercise, a large amount enters the bloodstream quickly and reaches the whole body at once, so the response is systemic from the outset rather than confined to the gut or the skin,’ he says.

‘Add to that the fact that the circulation is already working hard, and you have the conditions for a full anaphylactic reaction rather than a mild one.’

Even a brisk walk could potentially be life-threatening for Peter due to his condition

Peter said he suddenly recalled that in every allergic episode he had been exercising such as playing football, or lifting heavy equipment at work

Typically exercise-induced anaphylaxis begins when someone is a teenager or hits their twenties but can happen at any age. Diagnosis can be complex, says Dr Pereira, ‘because exercise is often only one part of the picture.’

‘Other factors, including alcohol, anti-inflammatory painkillers such as ibuprofen, infections, high pollen levels and hormonal changes, can lower the threshold at which a reaction occurs.

‘Then a combination lines up on one day: the food, the exercise, perhaps a painkiller, a drink the night before, high pollen, feeling run down. Any one of these lowers the threshold. Stack a few together and the person finally crosses it.’

What’s more he says the co-factors that lower the threshold tend to accumulate with age, but why this happens is not known.

Exercise-induced anaphylaxis accounts for roughly 5 per cent of all cases of anaphylaxis – but while it is rare, Dr Pereira says it is also probably under-recognised.

After the incident on the football pitch, it wasn’t until 12 years later, in 2014, that Peter had another attack. This time it occurred as he changed an axle on a truck – a physically taxing task that made him break into a sweat – after eating a cheese roll and a digestive biscuit

Suddenly he broke out in hives across his chest and neck, and he was quickly gasping for air.

‘I fell to the floor, clutching my throat,’ he recalls.

‘A colleague tried first aid, but I couldn’t breathe, I was thrashing around and they called an ambulance.’

He was rushed to hospital and this time diagnosed with atrial fibrillation (AF) – an irregular heart rhythm that starts in the heart’s upper chambers and causes fatigue, shortness of breath, palpitations, and dizziness.

He was given a beta blocker, medication to slow his heart rate and referred to a cardiologist.

Worried about the NHS waiting times he decided to use private health insurance, to see one quicker.

Days later a private consultant ran tests on his heart and looking confused told him: ‘There is absolutely nothing wrong with your heart.’

‘I was confused because the GP and NHS consultant had me convinced I had AF, now this guy was saying my heart was great,’ says Peter.

The cardiologist suggested Peter have more extensive allergy testing including skin prick testing as well as blood tests.

The pinprick tests – where tiny amounts of a potential allergen are pricked into the skin found that Peter was allergic to wheat and sulphites (found in wine and other alcohol).

From this doctors concluded that wheat or sulphites had caused the allergy but it was exercise that caused the severe reaction and anaphylaxis.

‘I suddenly recalled that in every episode I had been playing football, or lifting heavy equipment at work – basically exercising,’ says Peter.

He recalled hurrying for a bus and collapsing on board in 2008, with passengers desperately trying to administer first aid.

‘Thankfully someone called an ambulance,’ says Peter.

‘Other times I’d been doing strenuous things like football or heavy lifting – this was hardly more than a brisk walk.’

Dr Pereira says: ‘Exercise-induced anaphylaxis like any form of anaphylaxis, can be fatal if not recognised and treated promptly.

Once diagnosed people will be advised to avoid the triggers that cause the reaction, for example leaving at least four to six hours between eating a trigger food and exercising.

‘The relevant food proteins can still be circulating for several hours after a meal, so the four-to-six-hour window is designed to make sure they have cleared before exercise begins,’ says Dr Pereira. ‘It is a practical safety margin rather than a precise biological cut-off, and for some people the sensible gap is longer. ‘

‘Most people diagnosed with exercise-induced anaphylaxis are also prescribed adrenaline auto-injectors, such as an EpiPen,’ says Dr Pereira. These help by expanding the airways and tightening blood vessels.

‘They should also receive education about recognising symptoms early, stopping exercise immediately if symptoms develop, and using adrenaline promptly rather than waiting to see if symptoms worsen.’

Peter was given an EpiPen – an adrenaline injector designed for emergency use in people experiencing anaphylaxis and was told to avoid any exercise.

‘I thought I had it under control,’ he says.

‘I avoided wheat, never exercised or exerted myself and thought that was that.’

But he still must be careful.

In spring 2022, Peter was returning home from lunch with his wife and had to run to make the train.

‘It was only a 20-minute journey, but I felt unwell so I used my Epi-Pen when I reached my stop. Then I collapsed.’

His wife rang 999 explaining he was in anaphylactic shock.

‘My wife was pleading with them to send an ambulance,’ he recalls.

Thankfully an off-duty nurse came to help while they waited for an ambulance to arrive and Peter was taken to hospital.

Now Peter has two EpiPens and does gentle exercise but makes sure he doesn’t eat any wheat products for about six hours prior or four hours afterwards.

‘If we fly on holiday, I have to get there hours early as I cannot walk fast for the gate for the flight. I can’t lift luggage, I can’t queue, I can’t brisk walk in case I’ve eaten anything in the hours prior. It’s affected everything.

‘I love the NHS, but they are not equipped for the extensive allergy and anaphylaxis testing I needed to diagnose my condition,’ he says.

‘Without that, just running for a train could have killed me by now.’

anaphylaxis.org.uk

When Lex Banach gained nearly 3st (18kg) over six months, nothing about it made sense.

The US content creator, based in Wisconsin, hadn’t changed her diet or exercise regime.

Yet the figure on the scales climbed steadily from 11st (72.6kg) to 14st (90.7kg), while crushing fatigue, brain fog and uncontrollable food cravings turned her life upside down.

Every morning, the 29-year-old woke feeling as though she hadn’t slept. 

Her mood darkened – she found herself snapping at her partner over nothing and withdrawing from friends. She would tell herself she’d have just one cookie, only to eat the entire packet before she even realised what she was doing.

‘I just didn’t feel like me anymore,’ Lex tells the Daily Mail. ‘To be honest, I felt like I was losing my mind.’

Her doctors suggested she was suffering from anxiety and depression and referred her for therapy.

It wasn’t until 2023 that tests revealed the real culprit – sleep apnoea, a debilitating condition that affects an estimated ten million Britons and 84 million Americans and has been linked to weight gain, diabetes, heart attacks and strokes.

Lex Banach, 29, before and after her weight loss, which was aided by a CPAP machine. The device delivers a constant flow of pressurised air through a mask to prevent the airway from collapsing during sleep

In hindsight, Banach believes the signs were there all along.

By early 2022, frustrated by her weight gain, she was desperate for answers. She had tried everything she could think of, including coming off the birth control pill – a move some women make in the hope of reducing fluid retention and reversing stubborn weight gain linked to the drug.

‘It was kind of a wellness trend at the time to come off the pill,’ she says. ‘But it didn’t change anything.’

The scale continued to climb. So did her exhaustion.

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‘I had to nap every single day,’ she said. ‘I was just so exhausted all of the time.

‘I lost the ability to control myself around food, too. I’d tell myself I was just going to have one cookie, and then I’d eat the whole container.’

Looking back, she says the transformation was so gradual that she failed to recognise just how much she had changed.

‘The weight gain felt fast’, recalls Lex. ‘But the mental changes happened much more slowly.

‘I thought everybody was really stressed and struggling to wake up in the morning. We’d just been through a global pandemic, so I assumed that was everyone’s baseline.

‘I was constantly bickering with my partner. I was snappy. I wasn’t myself. It was a really tumultuous time.

‘Because it happened so gradually, the people around me didn’t really notice either. Then one day you wake up and realise you don’t recognise your own personality any more. I wasn’t the bubbly person I’d always been.’

As things worsened, Lex struggled to concentrate, while even simple tasks felt overwhelming. The brain fog was so thick she felt as though she were ‘wading through mud’.

Yet despite feeling exhausted all day, she rarely slept soundly through the night – one of the hallmark signs of sleep apnoea.

‘Mentally, physically, emotionally – I was desperate for answers,’ she says. 

By June 2023, Lex’s symptoms had become impossible to ignore. Her doctor referred her for an at-home sleep study to find out whether an underlying sleep disorder could be to blame.

Before going to bed, she attached a small sensor to her finger, which monitored her heart rate, oxygen levels and breathing throughout the night.

Lex’s weight climbed steadily from 11st (72.6kg) to 14st (90.7), while crushing fatigue, brain fog and uncontrollable food cravings turned her life upside down

The results were startling.

The test showed her breathing repeatedly stopped while she slept, disrupting her sleep 68 times in a single night. On average, she experienced an episode every eight minutes.

Doctors diagnosed mild sleep apnoea and told her she had likely been living with the condition for years without knowing it.

‘It was scary, but I was also so relieved to finally have an answer,’ said Banach. ‘I was surprised to hear it was only mild, considering how much it impacted me.

‘My partner at the time said he had noticed that I was sleep talking and wasn’t sleeping soundly. But I didn’t notice I would wake up that often.’ 

Sleep apnoea is a common disorder in which the muscles of the throat relax during sleep, causing the airway to repeatedly narrow or collapse.

This temporarily cuts off breathing – sometimes hundreds of times a night – jolting the body awake just enough to restore airflow, often without the person ever realising it.

Every time breathing stops, oxygen levels fall and the brain jolts the body awake just enough to reopen the airway.

Within a year of using the machine, the content creator had lost 4st (27kg), bringing her weight down to 10st (63kg) 

Night after night, those repeated drops in oxygen and surges in stress hormones place strain on the cardiovascular system, promote inflammation and disrupt the hormones that regulate appetite, metabolism and blood sugar – increasing the risk of everything from heart attacks and strokes to diabetes and weight gain. 

Common symptoms include loud snoring, gasping for air, morning headaches, excessive daytime fatigue and irritability – many of which Banach had experienced for years.

Experts say the condition can also make weight gain more likely through several biological pathways.

Repeated interruptions to sleep disrupt hormones that regulate hunger, increasing levels of ghrelin – which stimulates appetite – while suppressing leptin, the hormone that signals fullness.

The result is stronger cravings, particularly for high-fat and high-carbohydrate foods, alongside a greater tendency to overeat.

The relentless exhaustion caused by fragmented sleep also makes it far harder to stay active. A 2023 study found people with sleep apnoea were significantly less physically active than those without the condition, spending around seven hours a day sitting on average compared with five hours among healthy individuals.

Those with severe sleep apnoea were the least active, with daytime sleepiness and fatigue acting as major barriers to exercise.

Sleep apnoea is also linked to insulin resistance, making it harder for the body to process sugar efficiently and increasing the likelihood that excess calories are stored as fat – particularly around the abdomen.

Together, these effects create a vicious cycle: weight gain worsens sleep apnoea by narrowing the airway, while worsening sleep apnoea makes losing weight even more difficult.

While obesity is one of the strongest risk factors, sleep apnoea can affect people of almost any age or body type. 

Men, people over 40, those with a family history of the condition, smokers, heavy drinkers and people with conditions such as high blood pressure or type 2 diabetes are all at increased risk. 

Anatomical features – including a naturally narrow airway, enlarged tonsils or a recessed jaw – can also make the disorder more likely, even in people who are not overweight.

When Lex’s symptoms first began, she was working as a personal trainer and health coach and had successfully maintained a major weight loss for years. Looking back, she believes an extraordinary period of stress may also have played a role.

‘I’m not a doctor, but from everything I’ve researched since, I do wonder whether the amount of stress I was under contributed,’ she said.

‘It was 2021. We’d just come through Covid and were finally trying to get back to normal. I’d left the gym where I worked to build my online coaching business and social media following.

‘My relationship at the time wasn’t healthy. At the same time, the purchase of a condo fell through, it was the fourth anniversary of my mum’s death, and I was still carrying the grief from that, as well as other family bereavements I’d never properly processed.

‘I think my body was carrying an enormous amount of unresolved stress.’

Treatment for sleep apnoea depends on the severity of the condition. Patients are often advised to lose weight, avoid alcohol before bed and sleep on their side, while devices such as mandibular advancement splints can help keep the airway open in some cases.

For moderate to severe sleep apnoea – and some patients with milder disease and significant symptoms – the gold-standard treatment is a CPAP machine, which delivers a constant flow of pressurised air through a mask to prevent the airway from collapsing during sleep.

Banach was prescribed a CPAP machine, and found it helped almost instantly.

‘I feel like it took a few weeks for me to notice my mood and energy really start to shift,’ she said. ‘For weight, it took a few months; it wasn’t until October that my weight started to shift.’ 

Within a year, she had lost 4st (27kg), bringing her weight down to 10st (63kg).

A repeat sleep study in February 2024 showed her sleep apnoea had resolved.

But the improvement didn’t last.

After having to return her CPAP machine in April 2024, Banach was left without treatment. By May 2025, her symptoms had returned – along with 1.4st (9kg) of weight gain. 

Without health insurance, she has been unable to obtain another CPAP machine and is instead trying to manage her symptoms through exercise, meditation, yoga and a strict sleep routine.

‘I’m making do without it for now,’ she said. ‘I’ve looked at buying a CPAP machine myself and there are other devices on the market, but I haven’t found anything that’s both affordable and has consistently good reviews from people who’ve used them.

‘I still think CPAP is an incredible tool. I’ve even applied for a few brand partnerships with companies that make the machines because, honestly, that’s my best hope of getting one right now.

‘So I’m doing everything I can myself – exercising, eating well, sticking to a good sleep routine and trying to regulate my nervous system through meditation and other techniques I’ve learned. It’s helping, but it’s not the same as having the treatment I know works.’