What is the heat index and how does it affect your body. How can you recognize symptoms of heat-related illnesses. What are the best ways to prevent and treat heat exhaustion and heatstroke. How do humidity levels impact the apparent temperature you feel.

What is the Heat Index and Why is it Important?

The heat index, also known as the “apparent temperature,” is a measure of how hot it actually feels when relative humidity is combined with the air temperature. It’s a crucial indicator for assessing the risk of heat-related illnesses, especially during extreme weather conditions.

Why is the heat index so important? It provides a more accurate representation of how your body experiences temperature. On a humid day, your body’s natural cooling mechanism – sweating – becomes less effective. This is because the moisture in the air prevents sweat from evaporating efficiently, making you feel hotter than the actual air temperature suggests.

How is the Heat Index Calculated?

The heat index is calculated using a complex formula that takes into account both air temperature and relative humidity. While the exact calculations are intricate, here are some examples to illustrate how humidity affects perceived temperature:

• If the air temperature is 85°F (29°C) with 0% humidity, it will feel like 78°F (26°C).
• If the air temperature is 85°F (29°C) with 80% humidity, it will feel like 97°F (36°C).

These examples demonstrate how dramatically humidity can impact the way we experience temperature, potentially pushing us into unsafe temperature ranges even when the thermometer reading seems moderate.

Understanding Safe and Unsafe Temperature Ranges

Knowing the temperature ranges that can pose risks to your health is crucial for staying safe in extreme weather conditions. Let’s break down the different temperature ranges and their potential impacts on the human body:

• 82°F (28°C): This is the ideal environmental temperature for maintaining normal body temperature without additional cooling or warming.
• 90°F to 105°F (32°C to 40°C): In this range, you may experience heat cramps and exhaustion.
• 105°F to 130°F (40°C to 54°C): Heat exhaustion becomes more likely, and you should limit your activities.
• Over 130°F (54°C): This extreme temperature often leads to heatstroke, a potentially life-threatening condition.

It’s important to note that these ranges can be affected by factors such as humidity, sun exposure, and individual health conditions. Always err on the side of caution when temperatures rise.

Recognizing the Symptoms of Heat-Related Illnesses

Being able to identify the signs of heat-related illnesses can be lifesaving. These conditions can escalate quickly, so early recognition and intervention are crucial.

Heat Exhaustion Symptoms

• Heavy sweating
• Exhaustion or fatigue
• Dizziness or lightheadedness
• Fainting or feeling dizzy upon standing
• Weak but fast pulse
• Nausea and vomiting

Heatstroke Symptoms

• Reddish skin that feels hot to the touch
• Strong and fast pulse
• Loss of consciousness
• Internal body temperature over 103°F (39°C)

If you or someone around you experiences these symptoms, especially in hot weather, it’s crucial to take immediate action.

Preventing Heat-Related Illnesses: Essential Tips

Prevention is always better than cure, especially when it comes to heat-related illnesses. Here are some vital strategies to keep yourself safe in hot weather:

1. Stay hydrated: Drink plenty of fluids, even if you don’t feel thirsty. Aim for clear or light-colored urine as a sign of good hydration.
2. Replace electrolytes: When sweating profusely, be sure to replenish not just water but also essential electrolytes.
3. Dress appropriately: Wear lightweight, loose-fitting, and light-colored clothing in hot weather.
4. Avoid peak heat hours: If possible, stay indoors or in shaded areas during the hottest parts of the day, typically between 10 AM and 4 PM.
5. Acclimatize gradually: If you’re not used to hot weather, give your body time to adjust by gradually increasing your exposure to heat over several days.
6. Use cooling techniques: Take cool showers, use damp cloths, or sit in front of a fan to lower your body temperature.
7. Be aware of your surroundings: Pay attention to local weather forecasts and heat advisories.

By following these preventive measures, you can significantly reduce your risk of developing heat-related illnesses, even in extreme temperatures.

Treating Heat Exhaustion and Heatstroke: What You Need to Know

Knowing how to respond to heat-related illnesses can be crucial in preventing serious complications. Here’s what you should do in case of heat exhaustion or heatstroke:

Treating Heat Exhaustion

1. Move to a cooler environment: Get out of the heat, preferably to an air-conditioned space.
2. Cool down: Use cold, damp cloths around your body or take a cool bath.
3. Hydrate: Slowly sip water or sports drinks to replenish fluids and electrolytes.
4. Rest: Lie down and relax to help your body recover.
5. Loosen clothing: Remove any tight or unnecessary clothing.

Treating Heatstroke

Heatstroke is a medical emergency. If you suspect someone is experiencing heatstroke:

1. Call emergency services immediately.
2. Move the person to a cooler place.
3. Use cold compresses or a cool bath to lower body temperature.
4. Do not give fluids to drink, as this could cause choking.
5. If unconscious, place the person in the recovery position.

Remember, quick action can be lifesaving in cases of heatstroke.

The Impact of Climate Change on Extreme Temperatures

As our planet continues to warm, extreme heat events are becoming more frequent and intense. This trend has significant implications for public health and safety.

Rising Global Temperatures

Climate change is causing average global temperatures to rise. This increase may seem small on paper, but it has a significant impact on the frequency and severity of heat waves. Even a small rise in average temperature can lead to a disproportionate increase in the number of extremely hot days.

Increasing Frequency of Heat Waves

Heat waves are periods of abnormally hot weather lasting days to weeks. With climate change, these events are occurring more often and lasting longer. This puts more people at risk of heat-related illnesses, especially vulnerable populations such as the elderly, young children, and those with pre-existing health conditions.

Urban Heat Island Effect

In cities, the urban heat island effect can exacerbate the impacts of extreme heat. Urban areas tend to be hotter than surrounding rural areas due to the concentration of heat-absorbing surfaces like asphalt and concrete, as well as the lack of vegetation. As urbanization continues, this effect is likely to become more pronounced, further increasing the risk of heat-related illnesses in urban populations.

Adaptation and Mitigation Strategies

To address these challenges, communities and individuals need to adopt both adaptation and mitigation strategies. This includes improving urban planning to reduce heat absorption, increasing green spaces, enhancing early warning systems for heat waves, and educating the public about heat safety. On a larger scale, efforts to reduce greenhouse gas emissions are crucial for limiting the long-term increase in extreme heat events.

Special Considerations for High-Risk Groups

While everyone needs to be cautious during extreme heat events, certain groups are at higher risk of heat-related illnesses. Understanding these vulnerabilities can help in taking appropriate precautions.

Elderly Individuals

Older adults are more susceptible to heat stress for several reasons:

• Their bodies don’t adjust as well to sudden temperature changes.
• They’re more likely to have chronic medical conditions that affect their body’s response to heat.
• They may take medications that impair the body’s ability to regulate temperature.

For elderly individuals, it’s crucial to stay in air-conditioned environments during heat waves, stay well-hydrated, and have regular check-ins with family or neighbors.

Young Children

Children, especially infants and young kids, are vulnerable to heat for several reasons:

• Their bodies heat up 3 to 5 times faster than adults’.
• They may not recognize when they’re overheating.
• They rely on adults to keep them cool and hydrated.

Never leave children in parked cars, ensure they stay hydrated, and limit their outdoor activities during peak heat hours.

People with Chronic Medical Conditions

Certain health conditions can increase vulnerability to heat, including:

• Heart disease
• Diabetes
• Obesity
• Mental illness

If you have a chronic condition, consult with your healthcare provider about additional precautions you should take during hot weather.

Outdoor Workers

People who work outdoors are at increased risk of heat-related illnesses due to their prolonged exposure to high temperatures. Employers should provide:

• Frequent water breaks
• Shaded or air-conditioned rest areas
• Training on recognizing heat illness symptoms
• Flexible schedules to avoid peak heat hours when possible

By taking these special considerations into account, we can better protect those most vulnerable to the dangers of extreme heat.

The Role of Technology in Heat Safety

As our understanding of heat-related risks grows, so does the technology available to help us stay safe. From advanced weather forecasting to personal wearable devices, technology is playing an increasingly important role in heat safety.

Improved Weather Forecasting

Modern meteorological tools and techniques have greatly improved our ability to predict heat waves and extreme temperatures. This allows for:

• More accurate and longer-range heat forecasts
• Better planning and preparation for extreme heat events
• Timely issuance of heat advisories and warnings

Heat Index Apps

Smartphone apps that provide real-time heat index information are becoming increasingly popular. These apps can:

• Calculate the local heat index based on temperature and humidity
• Provide personalized heat safety recommendations
• Send alerts when the heat index reaches dangerous levels

Wearable Technology

Wearable devices are being developed to monitor an individual’s physiological responses to heat. These devices can:

• Track body temperature and heart rate
• Measure hydration levels
• Alert the wearer to potential heat stress before symptoms become severe

Smart Home Systems

Advanced home automation systems can help maintain a safe indoor environment during heat waves by:

• Automatically adjusting air conditioning based on outdoor temperatures
• Controlling window shades to reduce heat gain
• Monitoring indoor temperature and humidity levels

While these technological advancements are helpful, it’s important to remember that they should supplement, not replace, basic heat safety practices. Always use common sense and listen to your body when dealing with extreme temperatures.

Global Perspectives on Heat Safety

Heat waves and extreme temperatures are a global issue, affecting countries around the world. However, the approaches to heat safety can vary significantly based on local climate, culture, and resources.

Developed Countries

In many developed nations, heat safety strategies often include:

• Extensive use of air conditioning in homes, workplaces, and public spaces
• Well-developed early warning systems for heat waves
• Public education campaigns about heat safety
• Cooling centers for those without access to air conditioning

Developing Countries

In developing nations, heat safety can be more challenging due to factors such as:

• Limited access to air conditioning
• Less robust infrastructure for weather forecasting and public alerts
• Higher proportions of outdoor workers in agriculture and construction
• Limited resources for public health initiatives

In these contexts, heat safety strategies often focus on low-tech solutions like:

• Promoting traditional cooling methods (e.g., staying in the shade, using wet cloths)
• Community-based alert systems
• Adjusting work schedules to avoid peak heat hours

Cultural Adaptations

Different cultures have developed unique ways of dealing with heat over centuries. For example:

• Siesta culture in some Mediterranean and Latin American countries
• Traditional architecture designed for natural cooling in hot climates
• Dietary habits adapted to hot weather (e.g., spicy foods to induce sweating)

Global Collaboration

As extreme heat becomes a more pressing global issue, international collaboration on heat safety is increasing. This includes:

• Sharing best practices for heat wave preparedness
• Collaborative research on the health impacts of extreme heat
• Development of global heat health information systems

By understanding these global perspectives, we can learn from diverse approaches to heat safety and develop more effective strategies for dealing with extreme temperatures worldwide.

Hot and Cold: Extreme Temperature Safety

Hot and Cold: Extreme Temperature Safety

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Medically reviewed by Elaine K. Luo, M.D. — By The Healthline Editorial Team — Updated on September 17, 2018

Overview

If you’re planning to travel outdoors, be prepared to deal with all sorts of weather. This might mean extremely rainy days or extremely dry days, and from the hottest daytime hours to the coldest nights.

The human body has a normal core temperature between 97˚F and 99˚F, but on average, a normal body temperature is 98.6˚F (37˚C). To maintain this temperature without the help of warming or cooling devices, the surrounding environment needs to be at about 82˚F (28˚C). Clothes aren’t just for looks — they’re necessary to keep warm. You can usually bundle up in more layers during colder months, and you can use fans or air conditioners in warmer months to maintain a healthy core temperature.

In some cases, you may find yourself in an environment with extreme temperatures. It’s crucial to know what health concerns you may face as well as how to avoid any temperature-related health problems.

First, note that the temperature reading on a thermometer is not necessarily the temperature that you should be concerned about. The relative humidity in your environment can affect the temperature you actually feel, which is called the “apparent temperature.” Some example scenarios include:

• If the air temperature reads 85˚F (29˚C), but there’s zero humidity, the temperature will actually feel like it’s 78˚F (26 ˚C).
• If the air temperature reads 85˚F (29˚C), with 80 percent humidity, it will actually feel like 97˚F (36˚C).

High environmental temperatures can be dangerous to your body. In the range of 90˚ and 105˚F (32˚ and 40˚C), you can experience heat cramps and exhaustion. Between 105˚ and 130˚F (40˚ and 54˚C), heat exhaustion is more likely. You should limit your activities at this range. An environmental temperature over 130˚F (54˚C) often leads to heatstroke.

Other heat-related illnesses include:

• heat exhaustion
• heatstroke
• muscle cramps
• heat swelling
• fainting

Symptoms

Symptoms of heat-related illness depend on the type and the severity of the illness.

Some common symptoms of heat exhaustion include:

• sweating heavily
• exhaustion or fatigue
• dizziness or lightheadedness
• blacking out or feeling dizzy when standing up
• weak but fast pulse
• feelings of nausea
• vomiting

Symptoms of heatstroke include:

• reddish skin that feels hot to the touch
• strong and fast pulse
• losing consciousness
• internal body temperature over 103˚F (39˚C)

Treatment

If someone loses consciousness and shows one or more of the symptoms of heat exhaustion or heat stroke, call 911 right away.

To treat heat exhaustion, try to keep yourself cool with cold, damp cloths around your body and slowly take small sips of water until the symptoms begin to fade. Try to get out of the heat. Find some place with air conditioning or a lower temperature (especially out of direct sunlight). Rest on a couch or bed.

To treat heatstroke, cover yourself with cold, damp cloths or take a cold bath to normalize your body temperature. Get out of the heat immediately to a place with a lower temperature. Don’t drink anything until you (or the person experiencing heatstroke) receive medical attention.

Prevention

Stay well-hydrated to best avoid heat-related illness. Drink enough fluids so that your urine is light-colored or clear. Don’t rely solely on thirst as a guide to how much liquid you should be drinking. When you lose a lot of fluids or sweat profusely, be sure to replace electrolytes as well.

Wear clothing that is appropriate to your environment. Clothes that are too thick or too warm can quickly cause you to become overheated. If you feel yourself getting too hot, loosen your clothing or remove excess clothing until you feel cool enough. Wear sunscreen when possible to avoid sunburn, which makes it harder for your body to get rid of excess heat.

Try to avoid places that can get extremely hot, such as inside cars. Never leave another person, child, or pet, even for short periods of time.

Risk factors

Common risk factors that can cause you to be more susceptible to heat-related illness include:

• being younger than 4 or older than 65
• exposure to abrupt weather changes from cold to hot
• being overweight or obese
• taking medications such as diuretics and antihistamines
• using illicit drugs such as cocaine
• exposure to a high heat index (measurement of both heat and humidity)

As with high temperatures, don’t rely solely on the thermometer reading of environmental air for gauging cold temperatures. The speed of the wind and external body moisture can cause a chill that dramatically changes your body’s rate of cooling and how you feel. In extremely cold weather, especially with a high wind chill factor, you can quickly experience the onset of hypothermia. Falling into cold water can also result in immersion hypothermia.

Some cold-related illnesses include:

• hypothermia
• frostbite
• trench foot (or “immersion foot”)
• chilblains
• Raynaud’s phenomenon
• cold-induced hives

In addition to these illnesses, winter weather can cause major inconveniences for travelers. Always be prepared to deal with heavy snow and extreme cold, whether you’re on the road or at home.

Symptoms

When your body first drops below 98.6˚F (37˚C), you may experience:

• shivering
• an increased heart rate
• a slight decrease in coordination
• an increased urge to urinate

When your body temperature is between 91.4˚ and 85.2˚F (33˚ and 30˚C), you’ll:

• decrease or stop shivering
• fall into a stupor
• feel drowsy
• be unable to walk
• experience quick alternations between rapid heart rate and breathing too slowly
• shallow breathing

Between 85.2˚ and 71.6˚F (30˚C and 22˚C), you’ll experience:

• minimal breathing
• poor to no reflexes
• inability to move or respond to stimuli
• low blood pressure
• possibly coma

A body temperature below 71.6˚F (22˚C) can result in muscles becoming rigid, blood pressure becoming extremely low or even absent, heart and breathing rates decreasing, and it can ultimately lead to death.

Treatment

If someone passes out, shows multiple symptoms listed above, and has a body temperature of 95˚F (35˚C) or lower, call 911 immediately. Perform CPR if the person isn’t breathing or doesn’t have a pulse.

To treat hypothermia, get out of the cold as soon as possible and to a warmer environment. Remove any damp or wet clothing and start warming up the middle areas of your body, including your head, neck, and chest, with a heating pad or against the skin of someone with a normal body temperature. Drink something warm to gradually increase your body temperature, but don’t have anything alcoholic.

Even after you begin to feel warm again, stay dry and keep yourself wrapped up in a warm blanket. Seek medical help right away to minimize the harm to your body.

To treat frostbite, soak the affected area in warm water no hotter than 105˚F (40˚C) and wrap it in gauze. Keep any toes or fingers affected by frostbite separated from each other to avoid rubbing the areas against each other. Do not rub, use, or walk on frostbitten skin, as this can cause tissue damage. See your doctor if you still can’t feel anything on your frostbitten skin after 30 minutes.

Prevention

It’s essential to protect anyone experiencing early symptoms of hypothermia. If possible, remove them from the cold immediately. Don’t try to warm a person suffering from serious hypothermia with vigorous exercise or rubbing, as this can lead to further problems.

To prevent cold-related illness, take one or more of these measures when the temperature starts to drop:

• eat substantial meals regularly and drink plenty of water
• avoid drinks with alcohol or caffeine
• remain inside near a source of heat
• wear a hat, beanie, or something similar on your head to retain heat and gloves or mittens on your hands
• wear multiple layers of clothing
• use lotion and lip balm to prevent dryness of your skin and lips
• bring extra clothes to change into in case you get damp or wet
• wear sunglasses when it’s snowing or extremely bright outside to avoid snow blindness

Risk factors

Common risk factors for hypothermia and frostbite include:

• being younger than 4 or older than 65
• consuming alcohol, caffeine, or tobacco
• being dehydrated
• exposing skin to extremely cold temperatures, especially when exercising and sweating
• becoming damp or wet in cold temperatures

Last medically reviewed on January 10, 2017

How we reviewed this article:

Healthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

• Beat the heat weather ready nation campaign. (2014, July 28). Retrieved from 
  nws.noaa.gov/os/heat/index.shtml
• Cold related illnesses. (2016)
  health.mo.gov/living/healthcondiseases/hypothermia/illnesses.php
• Cold weather illness: Recognition, management, and prevention of cold exposure. (2016)
  uiltexas.org/health/info/cold-weather-illness
• Hypothermia. (2012, December 3)
  cdc.gov/disasters/winter/staysafe/hypothermia.html
• Mayo Clinic Staff. (2014, May 16). Heat and exercise: Keeping cool in hot weather
  mayoclinic.org/healthy-living/fitness/in-depth/exercise/art-20048167
• Mayo Clinic Staff. (2014, November 25). Heat exhaustion. Retrieved from
  mayoclinic.org/diseases-conditions/heat-exhaustion/basics/definition/con-20033366
• Tips to prevent cold related illness. (2014, January 25). Retrieved from
  dmhhs.dc.gov/release/tips-prevent-cold-related-illness
• Top ten Red Cross cold weather safety tips. (2015, February 18)
  redcross.org/news/article/Top-Ten-Red-Cross-Cold-Weather-Safety-Tips
• Warning signs and symptoms of heat-related illness. (2011, June 20)
  cdc.gov/extremeheat/warning.html
• Wexler, R. K. (2002, June 1). Evaluation and treatment of heat-related illnesses. American Family Physician, 65(11), 2307-2315
  aafp.org/afp/2002/0601/p2307.html
• Winter weather. (2015, April 23)
  cdc.gov/disasters/winter/index.html

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Medically reviewed by Elaine K. Luo, M.D. — By The Healthline Editorial Team — Updated on September 17, 2018

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This is the point when cold weather becomes dangerous

Some people are truly into the winter — and who doesn’t love the part where you get to snuggle up in a cozy sweater with a hot drink after a long day in the snow? But even if you aren’t someone who feels the cold, sometimes the weather can actually get so frigid that it’s dangerous to go out. But when is it too cold, and what should we do to stay safe? Wrap up and read on.

How cold is too cold?

The point at which cold gets dangerous is a higher temperature than you might think, especially if you live somewhere that frequently sees temperatures in the teens or lower. “It’s safe to be outside if the temperature is 32°F or above,” says David A. Greuner, MD, FACS, co-founder and director of NYC Surgical. “If the temperature falls between 13°F and 31°F, you should take breaks from the cold approximately every 20 to 30 minutes. If wind chill temperatures are 13°F and below, you should remain indoors.” Wind chill measures the true danger of weather conditions by factoring in how the low temperature and wind speed combine to remove heat from an exposed human face. To get a better idea, check out this chart created by the National Weather Service. For example, if the ambient temperature is 20°F and the wind speed is a breezy 10 mph, the wind chill is a significantly colder 9°F.

Even worse for us than the wind is water, warns Michael Richardson, MD, a Boston-based family medicine practitioner with One Medical. “During the winter, we try to insulate our body with warm clothes that trap in our heat, but what if that protective layer becomes drenched when we have to slog through the snow, or we trip in a slushy puddle? Wet clothes can lead to a rapid drop in your temperature, as the thermal conductivity of water is roughly 30 times greater than air.” This means water transfers heat away from your body more effectively than air, so you’ll get colder faster. That’s helpful in summer, but in winter, Dr. Richardson cautions, it can be a “fast track to hypothermia.”

Who is most vulnerable?

While 32°F is the limit for most people, some people are extra susceptible to the cold. Dr. Richardson explains, “Most people can get away with going out in the cold if dressed appropriately, but very young toddlers, infants, and the elderly have more difficulty regulating their [body] temperature. If you are going out with your child or an elderly person, you may want to plan ahead to minimize their exposure to the cold.” Janette Nesheiwat, MD, a family and emergency medicine doctor in New York, adds, “Cold injury is exacerbated by dehydration, drinking alcohol, and being ill or if you have an underlying medical disease like Raynaud’s disease, peripheral vascular disease (PVD), and circulatory problems.” If you’re already battling health problems, don’t add cold on top of it!

When does frostbite occur?

It’s most famously associated with Arctic explorers, but frostbite isn’t picky. “Frostbite can occur when a body part isn’t properly protected in the extreme cold,” Dr. Greuner warns. The colder the wind chill is, the quicker frostbite comes on. According to that National Weather Service wind chill chart, if it’s 0°F outside and the wind is blowing at 15 mph, creating a wind chill temperature of -19°F, you’re at risk of frostbite after being exposed for just 30 minutes.

The condition starts slowly and gets gradually worse. “The first symptoms of frostbite are sore, red skin, which is called ‘frostnip,’” Dr. Greuner says. “If you are experiencing these initial symptoms, get indoors immediately!” The extent of the damage is measured in four different degrees — similar to heat-related burns — Dr. Nesheiwat says. The severity of your injury, she tells us, “is determined by the depth of tissue freezing. First-degree frostbite starts when your fingers become painfully cold, may change color to red and then maybe turn grey or blue. You may get tingling and loss of sensation. The worst type of frostbite, the fourth degree, is deeper than the skin, and includes muscle, nerves, and bones, and can sometimes lead to amputation.” In this very advanced stage, Dr. Greuner adds, “the skin becomes very hard and cold to the touch and darkens; [depending on your natural skin color] it may look blue and later turn black.”

What precautions should we take?

If you can, stay inside when it’s below freezing outside — but if that’s not an option, start by dressing the part. In addition to a hat, gloves, scarf, and warm shoes or boots, Dr. Greuner suggests you layer up. “Wear three layers of loose clothing. Your first layer should keep you dry, the second should be made of an insulator like fleece, and the third should be wind- and waterproof,” he says. If you can, he says, take regular breaks from the cold, every 20 to 30 minutes. And if you notice any signs of frostbite, go straight inside.

Unfortunately, it’s not just frostbite you have to worry about. “Avoid strenuous activity, because events like heart attacks occur often in the cold,” Dr. Nesheiwat says. “Pace yourself, stay hydrated, and avoid alcohol because it gives you a false sensation of warmth.” Be aware that the impact of cold can creep up slowly. As Dr. Richardson explains, “Mild hypothermia presents subtly — you become short of breath, your heart beats faster, and you start to shiver. These are all signs that your body is trying to compensate for the cold, so take this as your first warning that it’s time to head indoors for some hot cocoa. ” We’ll take one of those too, please.

This article was originally published on Your Coffee Break.

What kind of weather is deadly for people?

The summer of 2022, like many previous ones, is very hot. At the end of June, residents of Moscow and other large cities were languishing in the heat – several cool days with rain are expected in July, but abnormally hot weather promises to return again. On such days, many people douse themselves in cool water and say that they are “dying from the heat.” The question arises – but really, at what air temperature does a person risk dying? Scientists have long been trying to figure out the limits of the endurance of the human body and are constantly making new discoveries. Let’s say right away that a person can feel bad after a few tens of minutes of being in the open sun. But there is an even more dangerous condition in which the human body receives the greatest damage.

Sometimes hot summers are more dangerous than freezing winters

Contents

• 1 Why is exposure to the sun dangerous?
• 2 The healthiest weather
• 3 Which countries have the hottest weather?
• 4 Which is better, heat or cold?

Why is exposure to the sun dangerous?

Obviously, the greatest harm to a person’s health is caused when he is outdoors. In summer, the air temperature even in the shade can reach 30 degrees Celsius, and in open areas this figure can be 10-20 points higher. Under the sun, the head becomes especially vulnerable – high temperatures heat the cerebral cortex, which leads to vasodilation. Because of this, a large volume of blood flows to the head, which can cause rupture of small vessels. Because of this, the entire central nervous system suffers.

In hot weather, you should never stay outdoors.

During hot weather, a person risks suffering from heat or sunstroke. These are two different phenomena - we talked about the differences in this material.

The most dangerous weather for health

But a person can suffer from extreme heat, even if he is in the shade. Bad things can happen if wet bulb conditions are established. The weather is such if the air temperature averages 31.1 degrees Celsius and the relative humidity is 95%. Under such conditions, the human body loses the ability to regulate body temperature through sweating, which is why heat stroke occurs with all the consequences. Experts believe that even perfectly healthy people with great endurance die in such conditions.

High humidity heat is always harder to bear

According to Professor Radley Horton, “wet bulb” conditions are deadly even if the person is wearing light clothing and carrying an unlimited amount of water. No matter how much he sweats, the body temperature will still rise – the only way to escape is to find a cool place with less humidity.

Why do +4 degrees feel cold in autumn and warm in spring? The answer is here.

Which countries are the hottest?

Hot and humid conditions are hardest to escape in South Asia, the coastal regions of the Middle East and southwestern North America. However, dangerous weather can form in other regions such as the US, Canada and even Russia. In the course of scientific work, the results of which were published in the scientific journal Science Advances, the above-mentioned Professor Radley Horton and his colleagues studied data from weather stations around the world collected from 1979 to 2017. They were able to detect about 7,000 occurrences of wet bulb conditions. It is highly likely that hundreds or even thousands of people died due to the heat in such weather.

Wet bulb conditions can occur anywhere except, perhaps, the cold parts of the Earth

As a result, it turns out that the summer heat is far from the most heavenly conditions. Residents of cold countries like Russia look forward to warm days and often even love the 30-degree heat. However, they do not realize that hot and humid conditions can cause the same damage to human health as winter frosts.

Which is better, heat or cold?

Moreover, some people are resistant to cold, while everyone suffers from heat. In 2021, scientists conducted an experiment involving 42 men – they were asked to sit in the cold until their body temperature drops to 35.5 degrees. Before being sent to a cold cell, they were tested. It turned out that among people there are mutants that have increased resistance to cold. You can read more about this discovery here.

Some people are resistant to cold

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At the end of the article I would like to ask what would you choose: an abnormally hot summer or a record frosty winter? Write about your choice and the reasons for such a decision in the comments, it will be interesting to read.

Human healthClimate on Earth

Temperature as the most important parameter for food safety

How microorganisms can get into food and what accelerates their reproduction

Bacteria enter food mainly:

• through production staff
  ;

• from raw foods
  ;

• from animals or pests;

• by air;

• through poorly washed equipment, inventory, from waste.

In order to live and multiply, microorganisms need:

The food worker cannot control acidity, oxygen supply, or moisture content, but he can control time and temperature.

The influence of temperature on the growth of microflora

The cold chain is a set of measures aimed at maintaining a constant temperature required for a particular product, along the entire path of its movement from production to consumer.

For identical groups of goods, the temperature storage regimes are similar. For example, for dairy products, confectionery and culinary products, this is most often from +2 to +6 С; for chilled offal and poultry – from -2 to +2 С or +4 С. However, for different manufacturers, depending on the ingredients, manufacturing technology and packaging, these parameters may vary slightly.

The temperature of food storage is extremely important, because under favorable conditions, the number of microorganisms will double every 20 minutes. That is, from 1 bacterium in 6 hours it will turn out … 262 144!

Temperature influence:

• at -18 °C – there is no growth in numbers, microorganisms “sleep”;

• from +1 to +5 ° C – most bacteria do not multiply or do it very slowly;

• from +5 to +63 °C – danger zone: rapid population growth; these are the most favorable temperatures for the reproduction of bacteria;

• from +63 to +75 ° C – most microorganisms do not multiply;

• from +75 to +100 °C and above – most microorganisms die.

Thus, keeping food products and ingredients at the right temperature is one of the most important things a food worker can do. After all, if you leave food for a long time at unacceptable temperatures for them, this will create conditions for the growth of microorganisms, sometimes to a dangerous level. In this regard, perishable foods, such as meat, fish, confectionery and dairy products, are at increased risk, but dry foods, such as rice and legumes, can also contain bacteria that will grow if the temperature is not controlled not only during storage, but also during cooking, cooling and heating.

How and with what to measure temperatures

Non-contact thermometers are designed for remote temperature measurement on the surface of an object. They are convenient, for example, to check the temperature in the car body when receiving products.

The probe thermometer measures the temperature of gaseous, liquid, semi-solid and granular substances. They can most accurately measure the temperature of the product inside.

The use of mercury thermometers in food enterprises is prohibited due to high risks.

During cooking, food must reach a certain temperature. How to measure the temperature to ensure the accuracy of the instrument readings? For meat and poultry, insert the probe thermometer into the thickest part for at least 15 seconds. If there is a bone inside, make sure the thermometer is not touching it – the bone may be hotter than the meat surrounding it, and therefore measuring its temperature may not indicate that the edible part has reached the right temperature.

For meats such as hot dogs or hamburgers, insert the probe through the vertical end. For casseroles and other similar dishes, insert the appliance into the center of the dish. It is important to ensure that the appliance does not contaminate food. To do this, it must be thoroughly washed and disinfected.

Over time, thermometers can lose their ability to measure temperature accurately, so they need to be calibrated and verified periodically. Designate a person responsible for this and ensure that valid supporting documents are in place.

Temperature control during receiving, storage and cooling

It is very important to control the temperature of products, especially perishable products, from the moment they are received. This will help determine if the cold chain has been broken during transport.

Frozen food with signs of defrosting and refreezing – ice crystals, frozen liquid, water stains, etc. – should not be accepted

The fact is that when frozen, microorganisms “fall asleep”, their vital activity slows down. When the product is defrosted, they begin to multiply actively. If the goods are refrozen, there will already be more microorganisms in it, and when they are thawed again, their number is likely to become critical.

Perishable food should be stored in the refrigerator at the temperature indicated on the label, usually +6 ºC or colder. Frozen – usually not higher than -18 ° C.

Check and record the temperature in refrigerators and freezers at least once a day. If the equipment cannot keep food at the required temperature, it must be repaired or replaced.

Arrange products in refrigerators and freezers correctly:

• when laying out, it is impossible to block the ventilation grilles, the goods should not interfere with the movement of air flows;

• loading of products into the chamber or showcase should be carried out only after it has reached the required temperature;

• it is necessary to observe the maximum allowable load of the equipment; it is impossible to lay out products above the permissible level;

• when loading products into cold stores, leave enough space for rotation and movement between products. Do not store food in bulk, as this interferes with air circulation and proper cooling.

Temperature control for cooking and reheating

Raw foods, such as meat or vegetables, may initially contain high levels of microorganisms. Therefore, it is important that food is thoroughly cooked to core temperature.
at least 75 °C
.

Optimal storage conditions for certain types of prepared meals and culinary products

• The readiness of meat and poultry is determined by the release of colorless juice at the puncture site and gray color on the cut of the product, as well as
  temperature in the thick
  . For example, for minced poultry meat, the recommended temperature is not less than 85 ° С , for cutlet mass – is not lower than 90 ° С .

• The readiness of products from minced fish and fish is determined by the formation of a fried crust and easy separation of meat from the bone. Recommended temperature not less than 70 °C .

It is recommended that you keep a record of the checks you have made, especially if the core temperature measurement is a critical control point within the HACCP system.

Temperature control during product storage

Finished products are stored in accordance with the technological map. There are optimal storage conditions for some types of products.

• For example, boiled meat, poultry and offal for the first and second courses are stored in the broth in which they were cooked at a temperature of +75 ° C until the release to the buyer for no more than one hour.

• Salads, vinaigrettes and sliced ​​​​components are stored unseasoned at a temperature of +2 to +6 ° C for no more than six hours.

• Raw minced meat – at a temperature of +2 to +6 ° C for no more than 12 hours.

• Minced meat for filling pies and pancakes is used within two hours after frying.

• Perishable food products after opening the package should be sold within 12 hours, subject to storage conditions.

• Egg powder after swelling for 30-40 minutes is subjected to cooking.

• Creams – custard, whipped cream, cottage cheese – are used immediately after preparation.

• Other types of creams are stored at the factory until they are used at a temperature of +2 to +6 °C for no more than 1.5 hours.

• Freshly prepared confectionery products with cream are stored at a temperature not exceeding +16 °С … +18 °С for no more than two hours. Further in the refrigerator at a temperature from +2 °C to +6 °C during the expiration date.

Hot product cooling

To ensure that food does not remain in the danger area for too long, it must be cooled down as quickly as possible. It is good practice to aim to cool food below 8°C within 90 minutes.

Techniques such as reducing the portion size, spreading food on an open tray or using ice, shock cooling in a special chamber will help with this.

Portioning of chilled and ready-to-eat meals, including cold appetizers and salads, culinary products, is recommended to be carried out in a room with an air temperature not higher than +15 °C or on tables with a cooled work surface.
In the absence of such a room or tables with a refrigerated surface, the portioning process should be carried out for no longer than 30 minutes.

Accounting for measurement results

The results of temperature measurement at any stage must be recorded. Checklists, magazines, and the like can be accepted as forms. Records must contain the date and time of temperature recording, identification
equipment
, FULL NAME. responsible for the entered information and features of corrective actions, if any.

Food defrosting

There are several ways to defrost products.

So, defrosting food in the refrigerator takes at least 24 hours, so this method requires planning ahead. Place the food on the tray in case liquid leaks out of the packaging. Food to be defrosted should be placed on the bottom shelf of the refrigerator.

Defrosting in cold water is faster than in a refrigerator and usually takes several hours depending on the weight of the food. Place the frozen food in a waterproof plastic bag and completely submerge it in cold running water at 21°C or lower. After defrosting, food should be cooked immediately.

To defrost food in the microwave, remove the packaging from the food and place it in a microwave-safe container. Then follow the instructions for defrosting food.

Food can also be thawed while it is being prepared, such as when you make soup from frozen vegetables.

Features of defrosting some products:

• It is not safe to defrost meat in water or on a hot stove. It is best to use a defroster 0…+6 °C, microwave or raw meat table.

• Can be thawed in water
  offal
  .

• It is better to defrost fish in the air or
  in cold water
  with a temperature not higher than +12 °C. To reduce the loss of minerals, it is recommended to add salt to the water at the rate of 7-10 g per 1 liter.

• Fish fillet, sturgeon fish are best thawed in the air.