Humidity: The Silent Threat That Affects Your Heart And Mind

Humidity is a climatic factor that directly influences our well–being, with effects that go far beyond the simple sensation of sticky heat. 

Health experts have found that high humidity can trigger serious problems, from exacerbating respiratory illnesses to increasing the risk of heart attacks and affecting mental health. Understanding how this natural phenomenon impacts the body is crucial, especially for those living in hot and humid areas.

Dr. Sadeer Al-Kindi, a cardiologist and researcher at Houston Methodist Hospital, explains that high humidity compromises the body’s ability to cool itself efficiently. “This significantly increases the risk of heat exhaustion and heat stroke,” he notes. 

The specialist also highlights the connection between humidity and the worsening of conditions such as asthma and allergies, since a humid environment promotes the proliferation of mold, dust mites, and other allergens.

Furthermore, recent studies cited by Dr. Al-Kindi suggest a link between humidity, high temperatures, and an increased risk of heart attacks, arrhythmias, and strokes. This additional stress on the cardiovascular system is due to poor thermoregulation and increased physiological strain on the body, factors that the heat index reflects more accurately than temperature alone.

Why does humidity make the weather feel so uncomfortable?

To understand how humidity affects our health, it’s first important to differentiate between its types. Absolute humidity refers to the actual amount of water vapor in the air, while relative humidity is the comparative measurement we often hear in weather reports, expressed as a percentage. However, to predict how “sticky” the day will feel, a more accurate indicator is the dew point.

This point is the temperature to which the air must cool to become completely saturated with water vapor. According to the U.S. National Weather Service, a dew point of 13°C or below indicates a dry and comfortable climate. When it’s between 13 and 18°C, the air begins to feel sticky, and if it rises above 18°C, the humidity becomes oppressive.

The reason humidity feels so bad is that it interferes with the body’s natural cooling mechanism: sweating. Sweat doesn’t cool us by itself, but rather by evaporating from the skin. In a humid environment, the air is already saturated with vapor, making it difficult for sweat to evaporate. This causes a buildup of sweat on the skin and a feeling of discomfort, which can lead to dehydration and, in extreme cases, heat exhaustion or heat stroke.

Dr. Al-Kindi emphasizes the seriousness of these conditions, especially for vulnerable populations such as older adults, people with heart disease, or those who work outdoors. The body’s inability to cool itself puts considerable strain on the heart and other vital organs, which can be fatal.

Lesser-known effects of humidity on health

Beyond heat problems, humidity can have a significant impact on other areas of health:

Difficulty breathing: High humidity can cause airways to narrow, known as bronchial constriction. This is particularly problematic for people with asthma, COPD, or allergies, as it exacerbates their symptoms. Humid environments are also ideal for the growth of allergens such as mold, dust mites, and pollen, which deteriorate air quality and aggravate respiratory conditions.

Affects cardiovascular health: Dr. Al-Kindi explains that heat and humidity put additional strain on the heart, forcing it to pump faster and harder to maintain body temperature. This stress can be two to four times greater on a humid day, increasing the risk of arrhythmias or heart attacks, especially in individuals with hypertension or a history of heart disease.

Impacts mental health: Although mental health is often associated with winter, humidity and high temperatures can also influence mood. A 2022 study found that relative humidity is a factor associated with symptoms of depression. Humid heat has been linked to higher levels of stress, anxiety, irritability, and difficulty concentrating. Seasonal Affective Disorder (SAD) can also manifest in the summer, with symptoms such as insomnia, lack of appetite, and anxiety.

How to protect yourself from the effects of humidity

Although high humidity is unavoidable in certain regions, taking precautions can minimize its impact on health:

• Monitor the weather: Check the forecast and heat index. Plan physical activity during the cooler hours of the day, such as the morning or evening.
• Stay hydrated: Drink water regularly, even if you don’t feel thirsty. Avoid alcohol and caffeinated beverages, as they can accelerate dehydration.
• Dress appropriately: Choose lightweight clothing made of breathable fabrics that allow sweat to evaporate.
• Seek shade: Wear sunscreen and stay in the shade to reduce wind chill. Remember that direct sunlight can significantly increase body temperature.
• Take refuge in air conditioning: Spend time in air-conditioned places like shopping malls or libraries to stay cool. If you don’t have air conditioning, open windows and use fans to improve air circulation.