As summer temperatures swell into the 90s and beyond in most cities, it’s a good time to take a look at the joint role heat and humidity play in heart disease mortality. And, thanks to a recent study published in the International Journal of Environmental Research and Public Health, health care practitioners now have more data that shows certain groups of heart disease patients may be more prone to heat-and-humidity-related deaths.  

The revealing new data, which was pulled from a sample of 120,544 cardiovascular deaths in 11 Chinese cities between 2010 and 2013, offers 5 key findings that could lead to new life-saving interventions.

1. Beware Low Temp & High Humidity: Low temperature plus high humidity was responsible for the majority of deaths — particularly for males, youth, low-education individuals, and people who live in coastal areas.
2. High Humidity Makes Temp Effects Worse: High humidity plus temperature exacerbated the heat effects for people with existing heart health problems.
3. Education Level Matters: Low education level was significantly linked to cold-but-humid related deaths, suggesting that certain populations require extra protection.
4. Coastal Areas More at Risk: High temperature and high humidity were associated with more significant risks in coastal areas than in inland areas.
5. Don’t Forget Relative Humidity: There was a positive correlation between the number of cardiovascular disease deaths and relative humidity.

Keep in mind that heart-related deaths caused by heat and humidity don’t just happen to people with existing cardiovascular disease. Everyone who spends time outdoors during hot temperatures should take safety precautions and understand the symptoms of heat exhaustion.  

Safety Precautions for Outdoor Summer Activity

• Drink at least 1-2 cups of water before, during and after outdoor activity
• Wear light-colored, breathable fabrics that repel sweat
• Apply sunscreen and wear a hat and sunglasses
• Take periodic breaks in a shaded area

Signs of Heat Exhaustion

• Headaches Cool, moist skin
• Dizziness and light-headedness
• Weakness
• Nausea and vomiting
• Dark urine

To learn more about the correlation between heat, humidity, and heart disease, check out the full study here.