This is your heart in hot weather

by Carolyn Thomas  @HeartSisters

Welcome to Lotus Land, where, alas, it’s been stinkin’ hot lately. This is tragically unfair, I think. I moved here to Canada’s beautiful West Coast decades ago in order to escape the kind of soul-sucking sauna that passes for summer back east.

And because uncomfortably hot weather is so deliciously rare here, few of us even have air conditioning, although I do have a little electric fan that I’ve started carrying around the apartment with me from room to room this past week.

Since my heart attack, I’ve learned a whole new reason to hate the heat.  I walk around feeling sick, clutching my little electric fan, a damp cloth pressed to the back of my neck, hot and cranky and looking like I’ve been hit by a very large bus. Here’s why heart patients can feel so much worse when those temperatures soar:  

Your Heart in the Heat

The heart is a fist-sized muscle that pumps blood through your arteries to all organs and tissues throughout your body. When ambient temperatures rise, the heart has to beat faster and work harder to pump blood to the surface of your skin to assist with sweating to cool your body.

If your body cannot cool itself enough, strain is put on the heart, and organs can begin to suffer damage – a potentially fatal condition known as heat stroke.

If You Have Heart Disease

Anyone can get heat stroke, but people with heart disease and other cardiovascular diseases are at greater risk.

If you have heart disease, your heart may not be able to work harder in the heat to maintain cooler body temperatures. Additionally, medications like diuretics to reduce water in the bloodstream are prescribed for many heart conditions, as are beta blockers. Each of these meds can reduce your ability to cool off in the heat.

Help Prevent Heat Stroke

  1. Wear loose-fitting, lightweight clothing.
  2. Protect against sunburn.
  3. Drink plenty of fluids (if you’ve been diagnosed with heart failure, talk to your doctor about fluid intake).
  4. Take extra precautions with certain medications (e.g. diuretics or beta blockers as listed above). Ask your doctor or pharmacist if any of your meds affect your body’s ability to stay hydrated or dissipate heat).
  5. NEVER leave anyone in a parked car, even for a very short time.
  6. Take it easy during the hottest parts of the day by finding a cool place.
  7. Take the time to get used to extreme heat (it can take a week or two to get your body used to it).

Exercising in the Heat

Simple rule: when it’s dangerously hot outside, don’t do it, unless you’re exercising inside a comfortably air-conditioned building. If you’re used to exercising indoors or in cooler weather, take it easy at first when temperatures begin to climb. Don’t increase the length or intensity of your workouts if you experience any heat-related symptoms.

Drink plenty of fluids. Dehydration is a key factor in heat illness.

If you’re unfit or new to exercise, be extra cautious when working out in the heat at all, especially if you have a heart condition in which your body may already  have a lower tolerance to the heat. Reduce your exercise intensity and take frequent breaks in the shade to rest and drink water.

Both the exercise itself and the air temperature can increase your core body temperature. To help cool itself, your body sends more blood to circulate through your skin. This leaves less blood for your muscles, which in turn increases your heart rate. If the humidity is also high, your body faces added stress because sweat doesn’t readily evaporate from your skin. That pushes your body temperature even higher.

If you plan to exercise outside during hot and humid weather, wear very light, comfortable clothing and work out only in the very early morning or late evening if possible.

Know the symptoms of heat exhaustion and heat stroke (below). If any of these symptoms appear, stop exercising and cool down immediately by dousing yourself with cold water. You may need to get medical attention. Heat exhaustion can progress quickly to heat stroke, which can kill you.

Symptoms of Heat Stroke

Heat stroke is a medical emergency. If you experience the following symptoms, apply cool water to your skin immediately and seek medical help.

  • High fever
  • Hot, dry skin without sweating
  • Pounding pulse
  • Dizziness
  • Nausea and/or vomiting
  • Confusion
  • Unconsciousness

If you experience heavy sweating with cool, clammy skin, along with symptoms such as fatigue, muscle cramps, headache, nausea, or fainting, you may have heat exhaustion – a form of heat sickness that can lead to heat stroke.

Get out of the heat immediately. Fan your body and apply cool water to your skin, remove extra clothing or any sports equipment, and drink cool (not cold) water or a sports drink; these steps can help you stop heat exhaustion before it worsens.

If these symptoms strike, have someone stay with you if possible who can help monitor your condition.   If you don’t feel better within 30 minutes, contact your doctor.

Remember: if you have signs of heat stroke, seek immediate medical help.

Source: Mayo Clinic, The Heart and Stroke Foundtion, and The Society for Cardiovascular Angiography and Interventions

NOTE FROM CAROLYN: I wrote much more about external factors that can affect women heart patients’ day-to-day life in my book, A Woman’s Guide to Living with Heart Disease (Johns Hopkins University Press). You can ask for it at your local library or favourite bookshop, or order it online (paperback, hardcover or e-book) at Amazon, or order it directly from my publisher, Johns Hopkins University Press (use their code HTWN to save 30% off the list price).


Thanks to cardiologist Dr. John P. Erwin III for sharing with us this study on the effect of hot weather on the heart:

  •  1. “Relation of Atmospheric Pressure Changes and the Occurrences of Acute Myocardial Infarction and Stroke”, Houck, Philip D. et al. American Journal of Cardiology , Volume 96 , Issue 1 , 45 – 51

Q: What’s your best tip to beat the heat?



13 thoughts on “This is your heart in hot weather

  1. Hi Carolyn, I found this link in another article you have up.

    I had my heart surgery last January. I was told by my physical therapist to watch the summer heat. Here in Ohio we never know how hot are summers are going to be. Plus we love to camp. Needless to say our summer was not too warm, and I really was not physically able to camp.

    I often wondered when I went in for my cardiac rehab – it was always so cold in there that I had to wear a jacket. But now I understand it all better. I never had the sweats.

    This year I am ready and really looking forward to summer to get here.
    Thanks for the info.

    Liked by 1 person

    1. Hello Susan – you’re right: we can never really predict exactly what summer weather will be like, except that we know from recent summers that record-setting extreme heat waves are now “normal”.

      This means that for many heart patients, we will need to take precautions that we’ve never had to think about before (like reducing time out in full sun – especially in mid-day, the worst heat of the day) and regularly taking shelter in the shade or in air-conditioned indoor spaces or vehicles, etc). When I walk with my walking groups in the summer, for example, we deliberately choose shady streets lined with big trees – and even criss-cross the road to seek shade on the other side of the street to avoid walking in the hot sun – and we plan our walks for very early in the day before things really heat up. No more walking around the high school track in full sun! The sun is NOT your friend when you’re a heart patient.

      Take care, stay cool out there! ♥


  2. I put my bathing suit on and stand in a cold shower. Then I put on a thin summer dress. The dress gets soaking and it helps you stay cool.

    Liked by 1 person

    1. I like that strategy, Gael! Speaking of cold showers. . . Today I had TWO cool showers (not ice cold but definitely very COOL) – first was in the morning as the day began to heat up, and another at about 6pm before dinner when things were definitely getting hotter. Thanks for sharing your tips to stay cool in the heat! ♥


  3. Everytime the temp goes into the 90s and I’m out doing errands I ask myself “Why do I feel so rotten and depleted?” Oh yeah, it’s the heat. You’d think I’d learn.

    I take diuretics and I’ve noticed I often am extremely hot but not sweating. I’ve probably been on the verge of overheating many times without realizing it. I just head for the A/C as fast as I can.

    A kerchief soaked in cold water around the neck is very helpful because it cools the large carotid arteries in the neck. Google “neck coolers for hot weather.” Years ago I had neck kerchiefs that had gel in them to hold water and I wore them when hiking.
    Enjoying a cool morning here in Denver… As soon as the afternoon sun starts beating in the west windows, I close the blinds which helps keep the heat down.

    Stay Cool!😎

    Liked by 1 person

    1. Hello Jill – I too had one of those gel kerchiefs I tied around my neck – I think I found it at a church craft sale many years ago. They really do stay cold for a few hours, as I recall. Sadly for me, after many ‘normal’ summers of not wearing it even once, it got sorted out one year and donated to the Sally Ann because I must have figured we just don’t need something like that here on the west coast. That was before the reality of climate change hit home, and the scary prospect of yet another low water/high forest fire season ahead. These record-breaking heat waves are just the beginning…

      That sense of hot dry skin with no sweating is also a symptom of heat exhaustion – and I too head for the AC, somewhere anywhere when/if that happens. My sister has just moved into her new house 90 minutes out of town and doesn’t own a portable fan (fans have been sold out of every store for hundreds of miles during this heat wave!) “Get thee to a mall!” I suggested! (Not for shopping, but for the AC!) I sure hope she takes my advice…

      Take care Jill – stay cool! ♥


  4. I hear ya, Carolyn! A tip I put into practice yesterday for the first time: Freeze container of water. (I used disposable aluminum lasagne pan). Place in front of fan. Lovely cool breeze wafts at you. Magic! I’m off to put an ice pack on the back of my neck now …

    Liked by 1 person

    1. Oooh! I’m going to fill up a lasagna pan with water right now! Thx for that “hot” tip, Deborah! My son is taking me to the computer store this morning but my plan is to go from his air-conditioned car directly into the air-conditioned store a.s.a.p.

      Take care and STAY COOL! ♥


  5. Good information even for those of us who live where it’s hot and steamy during the summer. I wilt like a dry plant when the temperature and humidity rise. Often wonder what’s wrong with me. Then I remember my heart.

    I walk the dog in the very early morning, garden in the early morning. Stay inside mid-day with air conditioning running.

    Liked by 1 person

    1. Excellent early morning strategies, Sara. My son told me last evening that he kept all of his apartment windows closed all day yesterday (to keep the hot air OUT!) and that seemed to help, whereas mine were wide open all day and it was as hot indoors as it was outside! Take care – stay cool! ♥


    1. Especially before the first heat wave! Here on the west coast of Canada, this weekend’s record-breaking high temps are rare – so we are all melting. Right now I have three fans on, all pointed at my face.

      Take care, stay cool. . . ♥

      Liked by 1 person

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