Avoiding this action is crucial during heatwaves, as advised by medical professionals: Neglecting Heat Safety Measures in a Heatwave is the One Action that Should Be Avoided.
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In the midst of a sweltering heatwave, many people might be tempted to rely on fans to keep cool. However, a new report from the Centers for Disease Control and Prevention (CDC) warns that using a fan when indoor temperatures exceed 90°F (32°C) can be dangerous.
According to the CDC, fans can exacerbate heat stress by blowing hot air directly onto the body, increasing core temperature and cardiovascular strain. This occurs because when the air temperature is hotter than your skin, the fan facilitates heat gain rather than heat loss.
Heat gain mechanism
At temperatures above about 90°F, your body usually loses heat to cooler air. But when the air is hotter than your skin (~95°F), the fan blows hot air, increasing your net heat gain rather than promoting evaporative cooling. This raises core body temperature and heart strain, especially in dry heat conditions.
Increased risk for vulnerable populations
Older adults and people with coronary artery disease are particularly at risk of heat strain with fan use in high temperatures, as a study showed fan use tripled cardiac strain in very hot, dry conditions.
Humidity factor
Fans may help slightly in humid heat below certain temperatures because sweat evaporation is aided. However, above 90°F, especially in dry heat, fans can worsen body heat retention.
CDC guidance
The CDC advises against fan use above 90°F because of these risks.
Alternative cooling methods
Dr. Eric Ascher, a family medicine physician at Northwell's Lenox Hill Hospital, explains that staying in air conditioning as much as possible is the best way to stay cool during a heatwave. Places like libraries, malls, or restaurants offer a cool respite.
Dr. Henry Young, associate professor in the Department of Emergency Medicine at The Ohio State University Wexner Medical Center, states that fans may actually cause more harm than good when it is very hot and dry. Instead, he suggests cooling your skin directly with cool showers, misting fans, spray bottles, and damp cloths on pulse points.
Dr. Young also recommends wearing light, loose-fitting clothes in hot weather.
In summary, during a heatwave where indoor temperatures exceed 90°F, fans can exacerbate heat stress by blowing hot air directly onto the body, increasing core temperature and cardiovascular strain, making them potentially dangerous without additional cooling methods like skin wetting or air conditioning. Heat stroke, the most serious form of heat illness, can cause passing out, sweating profusely, seizures, and having a very high body temperature. It's essential to stay vigilant and take necessary precautions to stay cool and avoid heat-related illnesses.
- In circumstances where mental health is a concern, it's crucial to consider alternative therapies and treatments, such as CBD, which have shown promise in managing anxiety and stress.
- During a heatwave, prioritizing health-and-wellness means seeking air-conditioned spaces instead of relying solely on fans when indoor temperatures exceed 90°F, as this could potentially worsen heat stress.
- Science has demonstrated that humidity plays a role in heat stress, as fans may help in humid heat below certain temperatures but could worsen body heat retention above 90°F, particularly in dry conditions.
- For people with medical-conditions like coronary artery disease, the risk of heat stress during high temperatures is even higher when using fans, making it essential to consult with healthcare professionals about suitable cooling methods.
