How to avoid heat-related illnesses

Countless cyclists eagerly anticipate the arrival of summer’s warm weather, longer daylight hours, green landscapes, and cycling events However, for others, summertime means scorching sunshine and soaring temperatures. Too much heat can wreak havoc on the body, making it crucial to ride out only when fully prepared for what Mother Nature has in store. Whether you’re embarking on a leisurely ride through the park or tackling a challenging mountain trail, arming yourself with the knowledge to beat the heat will be your best companion on many cycling adventures. Understanding how heat affects your body and knowing how to protect yourself from it is essential in preventing heat-related illnesses. Despite the challenges of riding in the heat, there are plenty of summertime rides to be enjoyed—even in places where it feels like summer lasts forever.

How the heat affects the body

The human body loses fluids through everyday functions like breathing, sweating, and bathroom use. However, hot weather causes the body to lose fluids at an even greater rate and requires all your systems to work harder to maintain normal functioning. Higher humidity accelerates the body’s vulnerability to heat even further because it interferes with the evaporation process and slows the rate at which your sweat can cool you down. Because the effects of extreme heat on the body are both severe and quick-developing, it’s crucial to pay close attention and understand your body’s signals when engaging in any physical activity in hot weather.

The body’s first response to above-average temperatures is to cool down by sweating. As you adapt to the heat, your body improves how you sweat: sweat rate increases as temperature and humidity rise, blood plasma volume increases (to assist with cooling and blood supply to skin and muscles), and you start sweating after a lesser increase in core temperature. While this may suffice in some cases, relying on sweat alone is not sustainable in many situations. For instance, spending extended periods of time in extreme temperatures, particularly in direct sunlight, is not recommended; no amount of sweating can make an unsafe decision safe.

While lost fluids can be replenished through drinking liquids and eating food, it’s easy to forget about nutrition amidst the excitement of a good ride. Failing to restore lost nutrients and fluids impairs bodily functions and can lead to dehydration and an increased risk of developing severe heat-related conditions, some life-threatening. Stay vigilant, recognize the early warning signs of heat-induced illnesses, and act promptly for safe and enjoyable summer adventures.

Common heat-related illnesses

Heat-related illnesses refer to a spectrum of conditions, but dehydration is the most commonly known one. Succumbing to dehydration can pave the way for a heat-induced ailment to develop, so knowing how to prevent it becomes paramount for ensuring a safe and enjoyable ride. Because anyone can get caught up in the joys of an exhilarating ride, it’s imperative to be aware of the symptoms of dehydration and how to respond to it. It’s also crucial to familiarize oneself with the most common heat-induced conditions and corresponding response strategies.

Dehydration

Dehydration results from your body receiving insufficient amounts of water, and numerous signs of dehydration can be misinterpreted or overlooked. Consider this scenario: during a long ride, you begin to experience widespread aches and pains. It's easy to attribute them to the challenging nature of cycling. However, these discomforts could be related to dehydration, which draws fluids from your tissues and results in generalized body aches. The severity of dehydration (mild, moderate, severe) directly depends on how water deficient you are. The first warning signs of dehydration include the following:

• Thirst
• Dry or sticky mouth
• Headache
• Muscle cramps
• Nausea
• Dry, cool skin
• Infrequent urination
• Dark yellow urine

As dehydration develops to severe dehydration, additional symptoms can appear, including:

• Dizziness
• Fainting
• Sleepiness or lethargy
• Confusion or irritability
• Sunken eyes
• Rapid breathing
• Rapid heartbeat

First aid: The moment you notice the beginning signs of dehydration, take action to prevent it from becoming more severe. Stop exercising, move to a cooler, shaded area, and replenish your fluids and electrolytes.

Heat exhaustion

Excessive sweating is the most common culprit of heat exhaustion, which happens when the body has lost a significant amount of either water or salt, or in some cases both. The core body temperature for those suffering from heat exhaustion is elevated but remains below 104 degrees. When left unaddressed, heat exhaustion can lead to a much more severe condition called heat stroke. Symptoms of heat exhaustion include the following:

• Headache
• Nausea
• Dizziness
• Weakness
• Irritability
• Thirst
• Heavy sweating
• Elevated body temperature
• Decreased urine output

First aid: Immediately move indoors or to a cooler, shaded spot and begin sipping cold water. Applying cold compresses (or, in the absence of compresses, splashing cold water directly on) to the head, face, and neck and removing unnecessary garments, including shoes and socks, can help cool down your core temperature. Core body temperature can be effectively lowered by immersing yourself in cold water. Recovering from heat exhaustion usually takes 24 to 48 hours. If your condition doesn’t improve or worsens, go to a clinic or emergency room immediately because you may have a heat stroke.

Heat stroke

Heat stroke occurs when your body can no longer control its temperature, putting it at risk of reaching temperatures above 104 degrees and as high as 106 degrees in just 10 minutes. Not only is heat stroke a fast-developing condition, but it can also leave its victims with lifelong disabilities or even result in death. Complications of heat stroke include: acute respiratory distress syndrome (ARDS), brain swelling, kidney failure, metabolic dysfunction, nerve damage and reduced blood flow to the heart. While it can be difficult to determine whether you’re looking at heat exhaustion or heat stroke, the two most recognizable characteristics distinguishing stroke from exhaustion are an elevated core body temperature of at least 104 degrees Fahrenheit and persistent neurologic symptoms. Heat stroke can present with:

• An elevated body temperature, often higher than 104 degrees
• Persistent neurologic symptoms, such as confusion, delirium, or altered mental state, such as not knowing where you are, slurred speech, or combativeness
• Hot, dry skin or profuse sweating
• Nausea
• Dizziness, passing out, or losing consciousness
• Headache
• Seizures

First aid: Move to a cooler place and call for help immediately. Guzzling down liquids to rehydrate may seem like a good idea, but experts advise against this; any liquids consumed should only be sipped until medical assistance arrives. If iced or cold water and cloth are available, apply a cold compress, prioritizing the head, neck, armpits, and groin. The objective is to lower your body’s core temperature to 101-102 degrees, immersion in cold water can be effective. A prompt trip to the emergency room is a must to avoid lifelong complications or death.

Heat rash

While it’s a rash, it doesn't mean it’s not painful or urgent. Heat rash is a skin irritation caused by excessive sweating in hot, humid conditions that develops when sweat ducts trap perspiration under your skin. Rashes vary in appearance and location:

• Range from superficial blisters to deep, red lumps
• Can appear as a red cluster of pimples or small blisters
• Usually appear on the neck, upper chest, groin, under the breasts, and in elbow creases

First aid: Relocate to a cooler, less humid environment to combat heat rash. Keep the rash area dry, and refrain from using ointments and creams unless specifically prescribed for your condition. Most cases of heat rash clear up independently, but some severe instances may require medical care.

Heat cramps

Heat cramps occur most often in those who sweat a lot during heavy physical activity, which exhausts the body’s salt and water levels. Muscle cramps form as a result of low salt levels in muscles and should not be ignored, as they can also indicate heat exhaustion:

• Muscle cramps, pains, or spasms in the abdomen, arms, or legs

First aid: Stick to drinking plain water and avoid salt tablets. If you have a snack, eat it. If there are carb electrolyte replacement liquids available, try those, too. If cramps do not subside or other health issues are a factor, seek medical attention.

Rhabdomyolysis (rhabdo)

Rhabdomyolysis is a medical condition associated with heat stress and prolonged physical exertion that results from direct or indirect muscle injury. Strenuous, ongoing physical activity can cause the breakdown, rupture, and death of skeletal muscle fibers. Upon the death of muscle tissue, the contents leak into the bloodstream, where they cause illness and put you at risk of grave health complications. Pay attention to the following signs of rhabdomyolysis:

• Muscle cramps/pain
• Abnormally dark (tea or cola-colored) urine
• Weakness
• Exercise intolerance
• Abdominal pain
• Nausea or vomiting
• Fever
• Asymptomatic

First aid: Immediately stop physical activity, move to a cooler location, and increase water intake. Because it can cause life-threatening conditions within, it is imperative that you seek medical care as soon as possible and specifically request to be tested for rhabdomyolysis. Moderate to severe cases may require intravenous (IV) fluids to prevent dangerous heart rhythms and loss of kidney function. When treated promptly enough, a full recovery is possible.

Heat syncope

Heat syncope is dizziness or fainting that results from getting up quickly from a sitting or lying position, standing for extended periods, or from physical exertion in the heat. High temperatures and forgoing acclimatization can contribute to an episode of heat syncope, as can other factors, such as diet and hydration. Heat syncope can often be treated at home if caught soon enough, so it’s essential to be aware of the symptoms:

• Fainting
• Dizziness
• Light-headedness during prolonged standing or suddenly rising from a sitting or lying position

First aid: Move to a cool, shaded place. Sit or lay with elevated legs to help promote blood flow to the heart. Slowly sip on water or a sports drink. While most episodes of heat syncope don’t warrant a trip to the ER and can be treated at home, it is imperative to continue monitoring vital signs to ensure that another heat-related ailment hasn’t already developed. Certain health conditions may also benefit from medical supervision.

Prevention of heat-related illnesses

Embracing outdoor summer cycling doesn’t mean compromising your well-being, but it will require strategic preparation. Planning routes and breaks in advance becomes necessary when riding in the heat. Integrating preventive measures into your cycling routine helps safeguard your well-being while riding in the heat. A checklist of hot weather riding essentials to refer to when getting ready to roll out helps ensure you don’t forget anything important.

Plan your route wisely

Strategic planning protects you from the summer heat during cycling adventures. Whether navigating familiar trails or venturing into “uncharted territory,” foresight can make all the difference. While well-known paths may require just a couple of alternate routes, unexplored terrain demands meticulous planning. Invest some time in route research and identify areas with ample shade and accessible water sources. These well-planned pit stops can offer relief from the heat when you need it most.

Timing is everything

Strategic planning plays a pivotal role in your ride prep. While we can’t control the weather, we have authority over when we embark on a cycling escapade. Strenuous activities (including interval training and long rides) during the hottest hours of the day are a recipe for trouble. Avoid planning outdoor rides from noon to 5 PM, when heat intensity is at its peak.

Conversely, early morning hours offer the relief of lower temperatures and milder UV exposure. Riding during this time enhances your cycling experience and mitigates some of the risks of developing heat-induced conditions. If you find yourself during warmer hours, exercise caution by adjusting your pace and power output accordingly. Another option is to allocate longer rides to the cooler hours and reserve heat training for shorter intervals. Pushing yourself to achieve personal records in extreme temperatures is not only unwise and can result in grave consequences, including heat-related illnesses. Always prioritize your well-being over performance—especially in challenging conditions.

Take breaks

Incorporating practical cooling strategies during your heat-intensive training is critical for your well-being. Regular breaks are an easy way to give your body the time needed to cool down. Optimize breaks with an array of simple yet effective cooling strategies. For extended rides, identify points where you can replenish with chilled beverages. The consumption of cold fluids plays a significant role in maintaining a lower core temperature, translating to enhanced performance. Don't hesitate to pack additional essentials, like extra water and electrolytes, and use shaded spots during breaks if you start feeling overheated. Minor adjustments can significantly impact your cycling experience in the heat, ensuring you ride safely and with optimal energy levels.

Stay hydrated and fueled

In the battle against scorching summer heat, staying well-hydrated and well-fueled is a game changer. Elevated temperature and humidity levels cause you to lose fluids and burn through calories much faster than in milder riding conditions. In fact, a fluid loss of approximately 1-2 quarts per hour via sweating in extreme heat is common, and not promptly replacing it can lead to dehydration. Because the body also loses salt during the sweating process, it’s imperative that sodium levels are restored. Being mindful of your body’s nutritional needs is important before, during, and after your ride:

• Pre-ride: Hydrating and fueling up before workout is critical for any endurance activity. The general wisdom is to drink 8 to 16 ounces of water one to two hours before the ride. Most people are chronically dehydrated because they simply don’t drink enough water during the day, so continuously hydrating the day before the ride can help bring your levels into the optimal territory and enhance kidney function. Remember, it takes at least 8 glasses a day to keep your kidneys in good working order.
• While riding: How much fluid intake a cyclist requires can differ from one to the next, but the standard recommendation is 20 ounces of fluids for every hour of riding for a 150-pound rider. Some adopt the 15-minutes rule: rehydrate by taking three gulps from your bottle every 15 minutes. It’s also important that you make up for the sodium and calories lost by consuming electrolytes and carbohydrates. You never know what you’ll need, so don’t be afraid to pack “extras.”
• Post-ride: After a grueling ride, protein and carbohydrates are the most important nutrients that need to be replenished. For optimized hydration, try a protein-based recovery drink post-ride as an alternative to carbohydrate-only options. Protein facilitates a quick recovery by carrying water to exhausted muscles. If you opt for water, pair it with a snack or meal containing protein, carbs, and sodium to ensure you’re restoring all the nutrients lost during those intense summer rides. To dial in your hydration, consider using your sweat rate to create an optimal hydration plan.

Incorporate practical ways to stay cool into your summer pre-ride routine because when you’re traversing under the blazing sun, you’ll be glad you did. For an ice-cold drink whenever you want one, simply partially freeze water bottles before topping them off with water. Going with insulated bottles helps prolong the longevity of chilled beverages. Cycling jersey aficionados can strategically use three water bottles, two frozen halfway and one three-quarters, for an even greater cool-down. Place the three-quarters frozen bottle in the center rear jersey pocket against your back and the halfway-filled bottles on either side. The bottle in the center will melt slower, giving you more time to enjoy its refreshing effects. Mountain bikers who prefer hydration packs can freeze the partially filled pack bladder and then top it off with water.

Keep your body cool

While you may be aware of water's important role in staying cool and hydrated, relying on water bottles alone in extreme temperatures is barely scratching the surface. Harness the potential of water beyond drinking by opting for one of the many methods that aid your body’s cooling mechanisms without hindering them.

Although many believe that dumping ice down their shirts or jerseys is the best way to bring down body temperature, experts advise against it because ice causes blood vessels in your skin to constrict and sends hot blood back to your core, counteracting the cooling efforts. Pouring cold water over the neck and forearms or using damp towels to wipe these areas offers practical heat dissipation. Cooling towels, equipped with unique technology that can lower the temperature of the towel to about 30 degrees below your average body temperature, are easy to use and might be worth considering. Alternatively, arm sleeves soaked in water and worn for a quick cool-down.

Remember: keeping your body temperature in check is of the utmost importance.

What you wear matters

While your body relies on sweating to cool itself, if the heat generated by sweating gets trapped by clothing. Suppose your sweat can’t evaporate to cool you down. In that case, a potentially unsafe health situation arises, demonstrating the significance of your clothing and gear choices and the need to consider uncontrollable variables such as humidity levels and winds.

One of the simplest ways to shield yourself from the summer sun and to reduce the chances of succumbing to lousy hot weather gear is by suiting up with moisture-wicking apparel specifically designed to help keep you cool. A well-vented helmet is also a must for anyone who plans to ride in hot weather—especially if it’s humid. Packing a waterproof windbreaker is also recommended for unexpected encounters with inclement weather.

Defending yourself against the sun’s harmful effects begins with protecting your skin, but that’s just the beginning. Alongside sunscreen, arm and leg sleeves, and other frequently used skin-protecting items, it is crucial to protect those easy-to-forget parts of your body, like your scalp and face, the back of your neck, ears, and eyes. While sunscreen and apparel can offer reasonable safeguards for your scalp, neck, and ears, relying on eyewear that provides the necessary protection is critical. Shield your delicate eyes with sunglasses or goggles that offer 100% UVA and UVB ray protection and are large enough to give the physical coverage you need.

Acclimating in advance might be necessary

Underestimating the impact of heat on your ride, especially when combined with humidity, can lead to heat-induced illnesses. An acclimatization program is essential for anyone who is going to ride in a climate drastically different from what they are used to. Acclimatization is a process that helps the body adapt to unaccustomed heat by gradually increasing training intensity over several weeks, depending on your program and needs. It's not about making exercise feel more comfortable; it's about enabling your body to function optimally during physical exertion.

Skipping much-needed acclimatization is one of the biggest mistakes an athlete can make because it robs your body of the opportunity to biologically prepare for intense exertion in a different climate. The human body generally performs better in cooler temperatures, so failure to acclimate can increase perceived effort and the risk of injury or illness. Research expected weather conditions so you can pedal out with everything you need to keep cool. Saunas, steam rooms, and hot yoga are good starting points because they offer shorter heat acclimation sessions. Foregoing AC on hot days can aid in gradual adjustment over more extended periods. If outdoor cycling is your only option, slowly increase the duration of your ride over time, and when you do ride, take frequent breaks and stay well-hydrated.

Pushing too hard in challenging weather is another commonly made mistake. While those used to hot and humid weather need less adjustment than those accustomed to drier conditions, everyone needs to ease into harsh riding conditions. To reduce the risk of temperature-related sickness, pay close attention to your body's responses and determine a tolerable intensity that doesn't strain it excessively.

Pack a summer emergency kit

Despite careful planning, situations can still arise. Prepare for the unexpected by carrying a summer emergency kit. It should include extra water, electrolytes, and snacks (bars, trail mix) essential for hydration and sustenance. If you’re venturing off the beaten path, consider water purification tablets or a straw water filter If you’re doing an urban ride, bring some cash so you can stop by a store or a gas station to not only cool down, but get a snack and a drink. Always bring a phone so you can reach out for support in case of emergency. Whether for yourself or someone else in need, this simple kit could make a significant difference.

Consider riding with someone else

One final suggestion for those who ride in high temperatures, particularly if venturing into unknown areas: consider riding with a friend or cycling group. Riding with others not only enhances the overall riding experience but also means there’s a helping hand around if needed. Adopting preventive measures and staying vigilant ensures that every pedal stroke is a step towards a safe and gratifying cycling experience for everyone.