Some heart attack symptoms can be more vague and subtle in women than they are in men. Often mistaken for anxiety attacks, the signs are harder to spot and often lead to later diagnosis and treatment. With heart attacks in women under 50 on the rise, specialists are keen to raise awareness about symptoms that shouldn't be overlooked, such as breathing difficulties and nausea. The advice comes ahead of World Heart Day, September 29.

More than 60% of heart attacks in women under 60 are linked to smoking. The risk is further heightened for smokers -- especially those over the age of 35 -- who also take a combined oral contraceptive pill containing the hormones estrogen and progesterone. Heart attacks in women under 50 have tripled in the last 15 years. Here are some of the warning signs that often go unnoticed.


Don't assume you'll have chest pains

"The chest pains that spread to the left arm and jaw, which are typical in men, are absent in women in around 40% of cases," explains the president of the French Federation of Cardiology. In women, these can be replaced by other signs such as nausea, heart palpitations during physical exertion, shortness of breath, pain in the middle of the back and unusual levels of fatigue. When chest pains do occur in women, they're more likely to be felt in the side and they aren't necessarily linked to exertion. Generally speaking, for men over 40 and women over 50, specialists recommend seeing a cardiologist or general practitioner as soon as chest pains are experienced with exertion.


Watch out for unusual difficulty in breathing


From anxiety attacks to smoking and asthma, shortness of breath can have many causes, which is why we don't always consider it a serious symptom. "The important thing is to note if the discomfort is new," explains sports cardiologist Dr Uzan, such as after running one and a half miles rather than your usual six, or climbing three flights of stairs that usually pose no problem. The specialist also suggests taking heed of remarks from friends and family, which can help flag up recent changes (e.g., "Keep up! You've got slow these days," "You didn't breathe like that before" etc.). Breathing difficulties when resting are also a warning sign.


Don't ignore palpitations

Although heart palpitations are benign most of the time, they're definitely worth keeping an eye on. These feelings of missed heartbeats or fast thumping (tachycardia) can be a telltale sign of heart disease. They are never normal when experienced with exertion, explains Dr Uzan. You should also see a doctor if your heartbeat is irregular and note the context in which it occurs (mealtimes, strong emotions, physical exertion, etc.).


Dizziness, nausea, fainting

Episodes of fainting or faintness associated with dizzy spells, vomiting, nausea, or loss of consciousness can be linked to heart-attack risks. "Regular" fainting -- called vasovagal syncope -- caused by low blood sugar levels or strong emotions, for example, can usually be felt approaching with symptoms such as sweating and nausea. Fainting episodes linked to the heart come with no warning signs.

Note that persistent digestive problems and unusual feelings of fatigue are symptoms which cardiologists also recommend following up with a doctor.