When temperatures climb, it's normal to feel a little sluggish. But underneath the surface, hot weather can do more than leave you sweaty and uncomfortable. It can also force your heart to work significantly harder to keep your body cool.
Most healthy people will cope well with these changes, but for those with underlying heart conditions, extreme heat can place dangerous strain on the cardiovascular system.
'The heart normally pumps around five litres of blood every minute. During periods of extreme heat, that workload can increase substantially as the body works harder to regulate its temperature,' explains Dr Francesco Lo Monaco, a private cardiologist in London and founder of The National Heart Clinic,
The cardiologist explains that this causes blood vessels to widen, our heart rate to rise and more blood to be directed towards the skin to help release heat. At the same time, sweating causes the loss of water and essential electrolytes, making it increasingly difficult to maintain stable blood pressure and circulation.
Research has consistently linked periods of extreme heat with higher rates of cardiovascular illness and death, particularly among people with existing heart disease.
People living with cardiovascular disease are most vulnerable during hot weather. That includes anyone with coronary artery disease, heart failure, a history of heart attack or stroke, or high blood pressure. Older adults, as well as people with diabetes, kidney disease or obesity, may also find it harder to cope with prolonged periods of heat.
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'Extreme heat can increase the risk of heart attacks, strokes, heart failure, atrial fibrillation and other serious heart rhythm disturbances, particularly in people who already have underlying cardiovascular disease,' says Dr Lo Monaco.
5 Heart-Related Symptoms You Shouldn't Ignore
These are the warning signs to look out for; if you're experiencing them, Dr Lo Monaco recommends seeking urgent medical assessment.
1. Chest Pain
Chest pain should never be dismissed as simply being caused by hot weather. It's the most common symptom of a heart attack, so you need to get it checked out.
2. Severe Breathlessness
Feeling a little more out of breath in hot weather can be normal, but severe breathlessness is different, especially if it comes on suddenly.
Severe breathlessness might look like not being able to get words out, or simply feeling unable to catch your breath.
3. Heart Palpitations
If your heart is racing, pounding or beating irregularly, don't simply write it off as a consequence of the heat.
Dr Lo Monaco says palpitations are another warning sign that should never be ignored, particularly in people with underlying heart disease.
4. Confusion
Heat can leave you feeling tired, but confusion is a different matter. While dehydration is a common cause of confusion, it can also be triggered by a heart attack because of a lack of oxygen-rich blood in the brain.
5. Fainting
Fainting may signal that your body is struggling to maintain blood pressure and circulation in the heat.
The NHS says fainting isn't always a major cause for concern; it's only considered a medical emergency when someone faints and they aren't breathing, cannot be woken up with one minute, don't fully recover, have chest pain or heart palpitations, have seriously hurt themselves or are shaking or jerking because of a seizure or fit.
Those who have fainted while exercising or fainted while lying down should also be taken to see a doctor immediately.
In other cases, fainting should still be something you talk to your GP about, just to check nothing is amiss.
How to Protect Your Heart During a Heatwave
The good news is that many heat related heart problems are avoidable with a few simple precautions. It's important to stay well hydrated, avoid intense exercise during the hottest part of the day, stay in cool environments, wear lightweight clothing and limit alcohol intake.
Dr Lo Monaco recommends, 'Good hydration, sensible activity levels, quality nutrition and looking after your overall cardiovascular health,' adding, 'Prevention remains one of the most powerful tools we have for protecting long-term heart health.'
Kate is a fitness writer for Men’s Health UK where she contributes regular workouts, training tips and nutrition guides. She has a post graduate diploma in Sports Performance Nutrition and before joining Men’s Health she was a nutritionist, fitness writer and personal trainer with over 5k hours coaching on the gym floor. Kate has a keen interest in volunteering for animal shelters and when she isn’t lifting weights in her garden, she can be found walking her rescue dog.
