man and woman on couch, gesturing as if they are too hot, with a fan pointed at them

KyoLife

Hot Topic: Tips to protect your heart when Mother Earth turns up the temperature

Ah summer! While the warmer, sunnier days of summer can bring many enjoyable things, hot weather can also have a negative impact on your cardiovascular system. Research shows that your cardiovascular system experiences extra stress when the temperature rises. And that can increase your risk of not only heart attack, but also arrhythmia (an irregular heartbeat) and heart failure.(1)

How serious is it? Temperatures over 100° Fahrenheit or even temperatures in the 80°s with high humidity can cause a dangerous heat index that can be hard on the heart. Recent research published in the journal Circulation found that when temperatures reach extremes of 109° or more—something that’s not uncommon in parts of Arizona, Florida, Nevada, and Texas—the number of deaths from cardiovascular disease may double or triple.2 Another study, presented at the American Stroke Association’s International Stroke Conference suggests that the more temperatures fluctuate during the summer, the more severe strokes may become.3

How Hot Weather Affects the Heart

Because the body has to work harder than normal to maintain a healthy temperature in hot weather, your blood pressure and heart rate can go up while your blood volume can go down due to dehydration. Here’s what happens: In hot weather, the body needs to cool down. This causes the blood vessels in your skin to dilate, leading to a drop in blood pressure.2 The heart then works harder to maintain blood pressure by pumping more forcefully and faster, potentially increasing your risk of experiencing a cardiovascular event.4

Dehydration due to the heat makes matters even worse. Sweating when the weather is hot can lead to fluid loss, which can reduce blood volume and further stress the heart. 4  And that’s especially true for people who play sports or exercise in the heat. Heat stress—which occurs when the body can’t regulate its core temperature—can also cause inflammation and damage to blood vessels, which can worsen existing heart conditions.5 Even if you aren’t active when outdoors, hot weather can worsen air quality, leading to increased exposure to air pollutants that can exacerbate heart disease and may increase the risk of dying from a heart attack.6

Are You at Higher Risk? 

If you already suffer from a pre-existing heart condition, you’re even more vulnerable to these effects. This is especially true for anyone with heart failure or coronary artery disease. Studies show that the uptick in heatwaves are a significant factor in cardiovascular deaths.7 Those living with certain heart conditions or risk factors like high blood pressure and are taking certain medications like beta blockers or diuretics may be at particularly high risk during a heatwave.8,9

Age also plays a significant role. This is because, as people age, their ability to regulate their body temperature and cope with heat stress decreases.10 Even if you haven’t reached your senior years, recent studies suggest that  living in a hotter environment can accelerate your biological aging just as much as smoking does.11

Tips to Protect Your Heart in Hot Weather 

Fortunately, whether you live in Phoenix or Miami or your area is just suffering through a random heatwave, there are steps you can take to protect yourself from the heat.

1. Stay hydrated. Drinking plenty of water helps to regulate your temperature. It also helps your heart pump more easily and keeps all your organs functioning properly. Remember to drink before you are thirsty, and avoid alcohol and caffeinated beverages, which can dehydrate the body.

2. Keep cool. If you don’t have access to air conditioning, a cold compress applied to your pulse points—areas where your veins are closest to your skin’s surface, such as your wrists, neck, temples and armpits—can help you cool down.

3. Be mindful of exercise. If exercising outdoors, choose cooler times of the day and ensure you’re well-hydrated.

4. Know the warning signs of heat distress. Spending too much time in extreme heat may lead to heat exhaustion and, in turn, heatstroke, two serious heat-related illnesses in which your body can’t control its temperature.

    • Heat exhaustion symptoms. Heavy sweating, nausea or vomiting, muscle cramps, tiredness, dizziness and fainting. Treatment: Move to a cool place, loosen clothing, use cold compresses, sip cool (not cold) water. If symptoms persist, call 911.
    • Heatstroke symptoms. Fever of 104 degrees or more, severe headache, behavioral changes, confusion, hot/red skin, no sweating, rapid heartbeat and loss of consciousness. Treatment: Heatstroke is a life-threatening medical emergency. Call 911 immediately. Quickly move the individual to a cooler place, use cold compresses, do not give anything to drink.

5. Timing is everything. Avoid being outdoors during the hottest times of the day, when the sun is at its strongest and temps are at their highest—typically between 11:00 a.m. and 1:00 p.m.

6. Be aware of air pollution. Avoid outdoor activities that could expose you to high levels of air pollution during heat events.

7. Dress right. Wear loose, light-colored clothing (to help reflect heat) that is made of a lightweight, breathable fabric like cotton. Add a wide-brimmed hat, sunglasses, and sunscreen.

8. Take supplemental Aged Garlic Extract (AGE). Research shows that AGE can protect your cardiovascular system in several ways, even in the heat. Clinical trials show that AGE reduces blood pressure in patients with uncontrolled hypertension as well as common blood pressure medications.12  It’s also been shown to lower cholesterol, prevent the buildup of plaque and calcium in arteries, and even improve circulation in the skin.13,14,15,16

Being prepared when the dog days of summer hit will not only keep you comfortable in the heat, but following these tips when the temperature rises might even save your life!

References

  1. Hot weather and your heart. British Heart Foundation. 2023. https://www.bhf.org.uk/informationsupport/support/practical-support/weather-and-your-heart#:~:text=Hot%20weather%20means%20your%20body,pressure%20from%20dropping%20too%20much.
  2. Alahmad B, Khraishah H, Shakarchi AF,et al. Cardiovascular Mortality and Exposure to Heat in an Inherently Hot Region: Implications for Climate Change. Circulation. 2020;141(15):1271-3.
  3. Kang M, Lee EJ, Jeong HB, et al. Abstract WP250: Diurnal Temperature Range as a Risk Factor for Ischemic Stroke Severity in Summer. Stroke. 2020;51(1).
  4. González-Alonso J, Crandall CG, Johnson JM. The cardiovascular challenge of exercising in the heat. Journal of Physiology. 2008;586(1):45-53.
  5. Xia R, Sun M, Li Y, et al. The pathogenesis and therapeutic strategies of heat stroke-induced myocardial injury. Frontiers in Pharmacology. 2024;14:1286556.
  6. Xu R, Huang S, Shi C, et al. Extreme temperature events, fine particulate matter, and myocardial infarction mortality. Circulation. 2023;148(4):312-23.
  7. Beck DL. A new threat to cardiovascular health: climate change, extreme weather and wildfires. Cardiology. 2025. https://bluetoad.com/publication/?i=843651
  8. Hospers L, Dillon GA, McLachlan AJ, Alexander LM, Kenney WL, Capon A, Ebi KL, Ashworth E, Jay O, et al. The effect of prescription and over-the-counter medications on core temperature in adults during heat stress: a systematic review and meta-analysis. EClinicalMedicine. 2024;77:102886.
  9. Münzel t, Khraishah H, Schneider A, et al. Challenges posed by climate hazards to cardiovascular health and cardiac intensive care: implications for mitigation and adaptation, European Heart Journal. Acute Cardiovascular Care. 2024;13(10): 731–44.
  10. White-Newsome JL, Sánchez BN, Jolliet O, et al. Climate change and health: indoor heat exposure in vulnerable populations. Environmental Research. 2012;112:20-7.
  11. Choi EY, Ailshire JA. Ambient outdoor heat and accelerated epigenetic aging among older adults in the US. Science Advances. 2025;11(9):eadr0616.
  12. Ried K. Garlic lowers blood pressure in hypertensive subjects, improves arterial stiffness and gut microbiota: A review and meta-analysis. Experimental and Therapeutic Medicine. 2020;19(2):1472-8.
  13. Varshney R, Budoff MJ. Garlic and Heart Disease. Journal of Nutrition. 2016;146(2):416S-421S.
  14. Nirvanashetty S, Panda SK. High potency aged garlic extract reduces cardiovascular disease risk factors in healthy participants: A randomized,double-blind, placebo-controlled study. Open Access Journal of Complementary & Alternative Medicine. 2023;5(1):585-93.
  15. Shaikh K, Kinninger A, Cherukuri L, et al. Aged garlic extract reduces low attenuation plaque in coronary arteries of patients with diabetes: A randomized, double-blind, placebo-controlled study. Experimental and Therapeutic Medicine. 2020;19(2):1457-61.
  16. Wlosinska M, Nilsson AC, Hlebowicz J, et al. Aged garlic extract preserves cutaneous microcirculation in patients with increased risk for cardiovascular diseases: A double-blinded placebo-controlled study. International Wound Journal. 2019;16(6):1487-93.

This article is for informational purposes only. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice.