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Temperatures in Pheonix have hit over 110 degrees for 31 days in a row. Mario Tama/Getty Images
  • Extreme heat impacts the body and mind in different ways.
  • When the weather is warm, our bodies try to maintain a normal internal temperature through sweating. However, if your body can’t self-regulate, it can cause heat exhaustion or heat stroke.
  • The way weather conditions affect mood is more likely associated with personal preferences than the actual temperature.

The first three weeks of July were considered the hottest on record, according to the World Meteorological Organization and data from the EU-funded Copernicus Climate Change Service (C3S).

This extreme heat has been associated with heatwaves in North America, Asia and Europe, and wildfires in Canada.

Given the rising temperatures, many people are concerned. Understanding how heat impacts your health is important in order to stay healthy and safe.

Dr. Eleni Horratas, an emergency medicine physician at Cleveland Clinic Akron General, said that the human body has a specific range of temperatures where the organs can function properly.

“Exposure to temperatures (cold or hot) outside that range results in your body trying to adapt, to keep itself inside the ‘normal range,” said Horratas.

As the body warms up, blood will start to spread to the surface of the skin and you’ll start to sweat more. As the sweat evaporates it will help you regulate your body temperature. However, if the temperature is too high, you don’t have enough fluids or the humidity is so high that sweat isn’t effectively evaporating, you can start to become overheated.

“Extreme heat results in an increased response of your body to keep a normal temperature and increase in demand in these pathways,” Horratas explained. “There are limits to what your body can adapt to, so significantly elevated temperatures can overwhelm the body’s intrinsic system and result in failure of the body to maintain a homeostatic environment which can ultimately result in organ failure (brain, kidneys, and heart are often affected).”

When the body can’t maintain a healthy temperature, it can result in heat exhaustion or heat stroke.

Signs of heat exhaustion include:

  • Heavy sweating
  • Fainting
  • Fast or a weak pulse
  • Cold, and clammy skin
  • Nausea
  • Vomiting
  • Muscle cramps
  • Tiredness
  • Dizziness
  • Headache

“In response to extreme environmental temperatures, our bodies try to maintain our internal temperature at 98.6 degrees,” said Dr. Justin Cahill, chair, Department of Emergency Medicine, Bridgeport Hospital in Connecticut. “This is most often accomplished by sweating. If someone is exerting themselves in the heat or has a pre-existing medical condition the body may not be able to maintain a normal internal temperature. This can lead to heat exhaustion or heat stroke.”

Heat stroke is an emergency and requires medical attention.

Symptoms of heat stroke include the following:

  • High body temperature of 103°F or higher)
  • Hot, red, dry, or damp skin
  • A fast or strong pulse
  • Headache
  • Dizziness
  • Nausea
  • Confusion
  • Passing out

Heat impacts serotonin levels, the primary neurotransmitter that regulates mood. Heat can therefore lead to increased levels of stress and fatigue, and decreased levels of joy and happiness.

“As temperatures soar, the effect is not just on our physical wellbeing and infrastructure, but also on our wellbeing and mental health,” said Jennifer Bahrman, PhD, a psychologist with UTHealth Houston. “Common side effects of heat on mental health include listlessness, changes in sleep patterns (e.g., insomnia), as well as heightened irritability, anger, anxiety, depression, and stress. “

Heat can also impact cognitive functioning, Bahrman explained. Specifically, it can impair working memory, concentration, attention, and reaction times. Deficits in this can lead to changes in an individual’s ability to effectively care for themselves, problem-solve, focus, make plans, and have good judgment.

“While the impact of heat on cognition is across all individuals and age groups, those with dementia are at particular risk related to this,” Bahrman stated. “They are at an increased risk for hospitalization and death as their ability to problem-solve and take care of themselves is already impacted by their neurocognitive impairment and is exacerbated by the effects of heat on cognitive functioning.”

Additionally, whether or not a person prefers cold or hot weather can also impact their mental health during a heat wave.

“How any weather conditions affect mood is more likely associated with personality and personal preferences than the actual temperature of hot or cold,” Mayra Mendez, PhD, LMFT, a licensed psychotherapist and program coordinator for intellectual and developmental disabilities and mental health services at Providence Saint John’s Child and Family Development Center in Santa Monica, California, stated.

For example, if a person is of a mindset that they prefer cooler temperatures, they may experience a lift in mood during the times of the year when it is cooler resulting in feelings of happiness and increased energy and zest for life, Mendez explained.

On the other hand, people who prefer cooler weather may experience increased negative moods when temperatures warm up. They may experience increased stress because they do not tolerate warm temperatures well. This means they may experience irritability, physical discomfort, and possibly pain from the increased propensity of heat-related swelling of the body, Mendez added.

Studies show that suicidal behavior decreases during months of colder temperatures.

There are factors that make someone more likely to be negatively affected by high temperatures.

People at higher risk include, those over the age of 65, infants and young children, and people who take medication that affect the ability to regulate temperature. “Medications that affect this can limit your body’s ability to adapt/cool itself resulting in overheating, and dehydration,” said Horratas.

Diabetes and heart disease also put people at higher risk.

Some people might be at higher risk for heat-related illness when they exert themselves, such as working outside or going on a hike.

For exertional heat illness, Cahill said risk factors include: lack of acclimatization, the patient’s fitness for the activity, dehydration, or the load they are carrying (clothing, gear, equipment).

“Try to avoid [the outdoors] during high sun (10 am-4 pm), and be sure to drink plenty of water/electrolyte fluids to replace volume lost in sweating,” Horratas stated.

“If you do need to be outside, be sure to take frequent breaks to cool off, limit caffeine intake or other supplements that can increase your risk of dehydration,” Horratas added.

On extremely hot days, Cahill recommends staying in the air conditioning.

“If you have to work outside, make sure you stay hydrated and protect your skin from the sun (sunblock and/or light clothing),” Cahill explained. “If you develop any feelings of weakness, dizziness or lightheaded try to find someplace cool. If you are not improved or feeling at all worse please seek medical attention.”

Extreme heat affects your mental and physical health in different ways.

In response to high temperatures, our bodies try to maintain a normal internal temperature. This is achieved through sweating. However, if your body can’t adapt to the heat, it can lead to heat exhaustion or heat stroke.

The mental effects of heat vary from person to person. For example, people who prefer cold temperatures may experience a negative mood shift when the weather is warmer. Also, high temperatures can affect sleep quality. Not getting enough sleep can also impact mood.

To protect yourself from extreme heat, stay indoors on hot days, stay hydrated and wear sunscreen outdoors.