Hot Weather and Heart Health

Heat can significantly impact the heart, particularly at extreme temperatures, high humidity, or prolonged heat exposure. While humans do possess natural mechanisms for cooling themselves down, such as sweating, excessive heat can strain this natural process and create stress on the cardiovascular system, leading to various effects on the heart. Understanding the potential impact of heat on the heart and taking proactive measures to prevent overheating and dehydration can help ensure the well-being and safety of individuals, particularly those at higher risk.

Does Heat Increase Blood Pressure?

During the winter, the cold weather constricts blood vessels to retain heat, causing blood pressure to be higher. In the summer, the hot weather causes blood vessels to dilate in order to keep cool, which can lower blood pressure. 

Does Heat Increase Heart Rate?

Yes, the heat does increase an individual's heart rate. To keep your body temperature cool, the heart has to pump faster and harder to circulate blood to the skin. During hot weather, the heart can circulate two to four times as much blood per minute in order to keep the body cool. 

Effect of Heat on the Body: Who is at Risk 

Both radiation and evaporation help to cool down the body, but they can also cause strain on the cardiovascular system. Many healthy individuals can tolerate hot and humid days, but for some, these stressors can be much harder to overcome. Some individuals may be more susceptible to heat stroke and heat-related illness. Some instances where an individual may be more at risk during heat waves and high humidity are: 

  • Elderly individuals, as well as very young children, can have a difficult time regulating body temperature.
  • Individuals who suffer from heart attack damage cause the body to struggle to pump enough blood to remove excess heat. 
  • High cholesterol can cause narrowed arteries limiting blood flow to the skin for cooling. 
  • Medications like beta blockers, diuretics (water pills), and other medications can interfere with the body's heat regulations.  
  • Alzheimer's disease, diabetes, Parkinson's disease, stroke, and other conditions can weaken the brain's response to dehydration and other important signals.  

How Does the Body Remove Heat? 

Hot and humid weather can take a toll on the healthiest of individuals, but for those with cardiovascular issues, a heat wave can be potentially dangerous. To keep the body at an optimal 97.9 to 99 degrees, it must shed some of the excess heat in one of two ways: radiation or evaporation. 

Radiation - When the temperature of the air around you is cooler than your body temperature, you will radiate heat into the air. To radiate heat, the body must reroute blood flow so more reach the skin to assist in the transfer of heat. In order to get more blood flow to the skin, the heart must pump faster and harder, circulating two to four times more blood a minute than an average day. 

Evaporation - Sweat evaporating off your body removes heat cooling the body. This works on dry days, but on humid days the sweat stays on the skin, and evaporation becomes much harder. Evaporation also places a strain on the heart as sweat evaporates off of the skin. Along with removing heat, sweat also takes sodium, potassium, and other minerals, which are vital components for muscle contractions like pumping the heart. 

Effects of Hot Weather on the Body: How to Protect Your Heart and Keep Cool

During hot summer days, it is important to check on family and friends, for healthy individuals and especially for those at risk. Keeping the body cool during times of excessive heat or humidity is crucial. Helping to keep your body cool can aid in taking any extra stress off the heart due to the heat. Here are a few tips to help keep you and your heart cool during the next heat wave: 

  • Drink Fluids: Staying hydrated is crucial to keeping your body cool. In order to sweat, you need water in your system, so it is essential to drink lots of water. Drinking water before you are thirsty is key. By the time your brain receives thirst signals, the body is already running low on water. Instead, try drinking a glass of water every hour to stay ahead of dehydration. It is also important to not drink too much alcohol or caffeinated beverages as they can increase dehydration. 
  • Monitor Weather and Time of Day: The sun is at its peak between noon and three pm, making it the hottest part of the day. Staying indoors or somewhere cool during these times as well as taking advantage of cooler mornings and evenings, can be helpful. Check the weather for heat advisors and plan outdoor activities around cooler days. 
  • Dress for the Heat: Wear lightweight, breathable fabrics like cotton or sweat-repellent fabrics. Sunglasses and hats are also a great addition to help provide shade. Be sure to apply sunscreen along with your outfit to protect your skin from the scorching sun.  
  • Take Breaks: If you plan on braving the heat, It is important to take rest and hydration breaks. Cooling off and taking time to rest in a shady place is key when dealing with extreme heat and humidity. If possible, try to avoid extreme physical activity that may overheat or exert the body. 

Heat can have a significant impact on both blood pressure and heart rate. Though effects vary among individuals, it is important to understand and manage these effects, especially for those at higher risk, such as individuals with pre-existing cardiovascular conditions, the elderly, and individuals on certain medications. Heat can lower blood pressure by widening blood vessels, while heart rates increase as your body works to regulate its temperature. Staying hydrated, seeking cooler environments, and avoiding prolonged exposure to extreme heat are key strategies for mitigating the heat's effect on blood pressure and heart rate. Recognizing how your body removes excess heat through radiation and evaporation helps develop strategies to stay cool and avoid dehydration. By staying hydrated, monitoring weather and time of day conditions, dressing appropriately, taking regular breaks, and avoiding strenuous activities during hot weather conditions, individuals can protect their hearts and sustain overall well-being. By being proactive and taking preventive steps, individuals can maximize summer enjoyment while minimizing the heat's effect on their blood pressure, heart rate, and cardiovascular health. It is always advisable to remain informed, listen to body signals, and prioritize self-care during hot weather for a safer and more enjoyable experience.