Preventing Heat Stress in Tactical Gear: Hydration, Cooling and Thermoregulation

Summer heat, hours spent in full kit, direct sun and constant physical activity. That's all it takes for your body to gradually lose its ability to dissipate heat effectively. Heat stress is more than just an uncomfortable feeling—it can reduce physical performance, impair concentration and affect decision-making. So how can you prevent it? Why isn't hydration alone enough, and what role do thermoregulation, properly configured gear and modern cooling technologies play?

In our previous articles, we introduced Qore Performance and explained the concept behind the ICEPLATE^® system. This time, we'll take a broader look at heat stress itself—why it develops when wearing tactical gear and what practical steps can help reduce thermal load in real-world use.

Heat Stress Begins Long Before You Notice the First Symptoms

Heat stress doesn't begin when the heat becomes unbearable. It starts much earlier—when your body generates more heat than it can effectively dissipate.

Every physical activity produces heat. Under normal conditions, your body regulates its temperature by sweating and allowing that sweat to evaporate from the skin. However, once you're wearing multiple layers of clothing, a plate carrier, or a backpack, shedding excess heat becomes much more difficult. Heat gradually builds up, forcing your body to work harder just to maintain a stable core temperature.

At first, the warning signs can be subtle. You may feel more fatigued than usual, find it harder to concentrate, or notice that your reactions are becoming slower. These early symptoms are easy to dismiss as nothing more than the effects of a hot day or poor physical conditioning, which is exactly what makes heat stress so deceptive.

If thermal load continues to increase and the body can no longer dissipate heat effectively, heat exhaustion may develop. In severe cases, it can progress to heat stroke—a life-threatening medical emergency that requires immediate treatment. Preventing heat stress is always far easier than dealing with its consequences.

TIP: Learn how to recognize the signs of heat stroke and provide effective first aid in our dedicated article.

ICEFLASK^® fits standard PRC-152 radio pouches, combining hydration with conductive cooling or heating without adding unnecessary bulk to the user's gear. Photo: Rigad

Hydration Is Essential—But It Isn't the Whole Answer

Proper hydration is one of the most effective ways to prepare your body for physical activity in hot conditions. Yet many people don't start drinking until they feel thirsty—sometimes even later. By the time thirst sets in, your body is already beginning to lose the fluids it needs to perform at its best.

During prolonged activity in full kit, the body loses more than just water. Sweat also depletes essential electrolytes, particularly sodium, potassium and magnesium. In high temperatures or during intense physical exertion, replacing fluids with water alone may not be enough. Replenishing electrolytes helps maintain proper fluid balance and supports normal physiological function.

Even a well-planned hydration strategy, however, cannot prevent heat stress on its own. The water you drink is essential for normal body function, but it cannot efficiently remove the heat trapped beneath multiple layers of clothing and protective equipment. If your body is unable to dissipate heat effectively, your core temperature will continue to rise regardless of how much water you consume.

Hydration is therefore the foundation of heat stress prevention—but it is only one part of the equation. Equally important is giving your body the ability to shed excess heat as efficiently as possible.

Functional Clothing and Ventilation Help the Body Stay Cool

During physical activity, sweating remains the body's most effective cooling mechanism. Sweat itself, however, does not cool the body. Cooling occurs only when it evaporates from the surface of the skin. If moisture becomes trapped beneath multiple layers of clothing or protective gear, the body's natural cooling process becomes far less effective.

That's why the base layer plays such a critical role. Its job isn't simply to move sweat away from the skin—it also helps accelerate evaporation. Functional fabrics are designed to transport moisture away from the body, while cotton absorbs and retains it. Once clothing becomes saturated, it not only feels uncomfortable but also creates a warm, humid microclimate where excess heat is much more difficult to dissipate.

Ventilation throughout the entire gear system is equally important. The less air can circulate between your body and your equipment, the faster heat and humidity build up. This is one of the main reasons why wearing a plate carrier, backpack or other protective equipment dramatically increases thermal load compared to moving without additional gear.

One solution is to incorporate ventilation components that create an air gap between the body and the equipment, allowing air to circulate more freely. A good example is ICEVENTS^® from Qore Performance. Their open 3D structure improves airflow beneath a plate carrier, backpack or padded waist belt, helping reduce both heat and moisture buildup where thermal load is typically greatest.

Additional Factors That Affect Thermal Comfort

Choosing the right clothing is only part of the equation. Several other factors can help reduce thermal load during prolonged wear of tactical gear. While none of them is a standalone solution, together they can significantly improve endurance and overall performance.

• A quality moisture-wicking base layer helps move sweat away from the skin and promotes evaporation.
  
• Breathable clothing and proper layering improve airflow and moisture management.
  
• Ventilated backpack suspension systems create an air gap between the pack and your back, improving airflow.
  
• Spacer padding on plate carriers and backpacks enhances ventilation in areas where heat and moisture tend to accumulate.
  
• Regular breaks in the shade, whenever operationally possible, allow the body to reduce thermal load.
  
• Consistent hydration and electrolyte replacement support the body's natural thermoregulation and help replace fluids lost through perspiration.
  

None of these measures is a universal solution on its own. Together, however, they create conditions that allow the body to cope with high thermal load far more effectively.

ICEPLATE^® and ICEFLASK^® are designed for extended wear in tactical gear, combining hydration with conductive thermoregulation to help manage thermal load. Photo: Rigad

Active Thermoregulation Takes Heat Management a Step Further

Proper hydration, functional clothing and improved ventilation can significantly reduce thermal load. In some situations, however, they may not be enough. Long hours in a plate carrier, extended duty in hot weather or multi-day training exercises place the body under sustained thermal stress while limiting its natural ability to dissipate heat.

This is exactly the challenge addressed by Qore Performance. Rather than focusing solely on hydration, its systems use water as a medium for conductive thermoregulation. In direct contact with the body, cold water absorbs excess heat, while warm water helps retain body heat in cold environments. In both cases, the principle is the same—heat transfer through conduction.

The best-known example is ICEPLATE^®, which combines hydration and thermoregulation in a single wearable system. The same concept is applied to the compact ICEFLASK^®, designed to fit standard PRC-152 radio pouches and provide cooling or heating without taking up additional space on the user's kit. Both systems expand the role of water beyond hydration alone, without relying on batteries, fans or other electronic components.

If you'd like to learn more about how the ICEPLATE^® system works, we've covered it in detail in a dedicated article. We also explain how it differs from a conventional hydration bladder and why it uses water for both hydration and thermoregulation.

When Thermoregulation Makes the Biggest Difference

The benefits of thermoregulation are unlikely to be noticeable during a short hike or a one-hour range session. Its value increases with the duration of physical activity, the amount of gear being worn and the ambient temperature. The longer your body generates heat—and the harder it is to dissipate it—the more important the measures discussed in this article become.

Typical examples include:

• Multi-day firearms training courses, where long hours are spent outdoors in direct sunlight while repeatedly handling firearms and wearing full kit.
  
• Extended foot movements or long-distance marches, where fatigue gradually accumulates and opportunities to cool down are limited.
  
• Operational duty during the summer months, when protective gear may be worn continuously for many hours regardless of activity level.
  
• Training exercises and tactical drills, where maintaining focus, situational awareness and sound decision-making is critical even after prolonged exposure to heat.
  

These are the situations where thermal comfort becomes much more than a matter of convenience. Reducing thermal load helps preserve energy, maintain concentration and minimize mistakes caused by fatigue.

Heat Stress Is Preventable

Heat stress doesn't have a single cause, so there isn't a single solution. Preventing it requires a combination of measures that work together to help the body regulate its temperature more effectively.

Proper hydration and consistent fluid intake are the foundation. Equally important are a moisture-wicking base layer, well-designed gear that promotes airflow and other measures that help reduce heat buildup around the body.

When thermal load becomes especially high—during extended training, firearms courses, operational duty or long movements in full kit—conductive thermoregulation can provide another layer of protection. Systems such as ICEPLATE^® and ICEFLASK^® are not intended to replace hydration or good equipment choices. Instead, they complement them by helping the body manage heat more effectively.

Ultimately, the goal isn't simply to feel more comfortable. It's to maintain physical performance, mental focus and sound decision-making for as long as the mission demands.

Further Reading

• Qore Performance: Water as Both Cooling and Heating in Tactical Gear
  
• ICEPLATE^® vs. a Traditional Hydration Bladder: What's the Difference?