Esther Stanhope was at Gatwick airport in 2017 and about to board a flight to Amsterdam when she began to feel slightly strange.
"I couldn’t get my breath but thought it must be down to rushing around and I boarded the flight and was fine," says the author and mother-of-two, from London.
"But on the return journey, it happened again so I thought it may be something to do with airports. Friends suggested it could have been a panic attack or maybe asthma."
Six weeks later, a similar incident occurred.
Stanhope – who was only 45 at the time and a regular walker - was in the US visiting family when she went to an exercise class with her sister-in-law.
"The class was really intense and I started to feel sick and dizzy," she says. "I went outside thinking I was going to collapse and be sick but put it down to jetlag or fatigue. My left arm felt slightly numb, but I thought no more of it. Instead, I went back inside and finished off the class.
"But when I arrived in London the next day, I began to feel odd again.
"At the airport, I was breathless again and sweating, so I rang my GP hoping I could make an appointment. When I told them my symptoms – and mentioned that my father had died of a heart attack when he was 40 - they said I should make my way straight to A&E."
Stanhope followed her doctor’s instructions but was convinced that nothing was seriously wrong.
"I called up my assistant on the way to A&E to tell her to postpone my meetings for a couple of hours," she says. "But when I got to the hospital, I was seen by a cardiologist who told me I wouldn’t be going back to work for at least a couple of days and she wanted to do more tests.
"I couldn’t believe what I was hearing, I really felt there was nothing seriously wrong."
But there was. Tests showed that Stanhope, a previously healthy woman, had suffered a heart attack.
She was actually lucky to be diagnosed. Two women are dying needlessly every day because of a ‘heart attack gender gap’ where they do not receive equal treatment to men, according to a report by the British Heart Foundation.
It means an estimated 8,000 women in England and Wales have died from heart attacks in the last ten years, thanks to poor awareness of heart disease in women and a lack of diagnosis and treatment.
Watch: Misdiagnosis of heart attacks in women
"I spent a week in hospital and for the first time in ages, I enjoyed simply relaxing," says Stanhope.
"The doctors diagnosed a blocked artery to my heart and inserted a stent to open it. I was put on statins and other drugs and although physically I healed quickly, emotionally it was a different matter.
"It took me quite some time to accept the fact that I’d had a heart attack, the same thing that had killed my father at such a young age. I’d inherited high cholesterol and high blood pressure and of course, thoughts turned to my children who are now 15 and ten and what would have happened to them if I’d died."
The impact of the attack made Stanhope, who is also a speaker at events around the world, make some lifestyle changes.
"I’m much more mindful of my health now and I’m so careful to not overdo it," she says. "I watch my diet, I regularly do yoga and walk at least 13,000 steps a day.
"I’m more conscious of slowing down and giving myself a break when I need it. My family are always telling me to slow down but I love my work and it’s more stressful for me to not be working than to work, but I need to pace myself.
"The heart attack has made me reevaluate and rethink what ‘success’ means – is it surviving? Is it making sure your children are happy? Is it having some ‘me-time’?"
She warns other women to look out for the signs that she ignored for over six weeks. "If you feel a bit weird, can’t catch your breath or have a strange sensation in your arm go to A&E," she says. "Don’t ignore it like I did. I was lucky, but so many women aren’t."
Stanhope is the author of Goodbye Glossophobia – Banish Your Fear of Public Speaking.
Watch: Heart attack symptoms can be different for women