People still sweat while wearing a ThermAparel Cooling Vest because they are designed to assist the body's natural cooling process, not replace it entirely. Cooling vests do not change the environment, making it cooler or changing humidity like air conditioning. You never want your body to stop sweating in the heat; if it does, seek immediate emergency help (call 911). Here are the main reasons:
How Sweat Works
Sweating is the body's primary cooling mechanism: Sweating allows the body to regulate its core temperature through evaporation. Sweat provides the element to evaporate. A great example of this is when you get rubbing alcohol on your skin; it suddenly feels cold for a split second. The evaporation of the rubbing alcohol causes this cold feeling. Neither the alcohol nor the sweat made you cooler. So think about that for a second: if something prevents your sweat from evaporating, like humidity levels or clothing, PPE, and lack of airflow, you will receive no cooling. Even with an UnderCool, UltaraCool, and RallyWrap cooling vest, your body produces heat during physical activity or in hot environments. Sweating remains necessary unless the vest can fully offset the heat load.
Supplemental Cooling and Evaporation
Cooling vests are a supplemental cooling for your body. Most work by absorbing and dissipating heat or providing evaporative cooling (some act like "artificial sweat" by evaporating water from the vest itself). In especially humid conditions, the effectiveness of natural sweating and evaporative cooling vests is reduced; for example, if the humidity level is at 100%, you are not receiving any cooling; at 90% humidity, you are reviving 10% cooling. An evaporative vest also needs a continuous airflow supply to evaporate the water or cool it down by the air temperature. If these conditions are unavailable, like on a very humid day or in temperatures above 98 degrees, your body will heat the water in the vest. If that water gets too warm, it will reverse and start heating you!
Our Tech
Thermapparel vest: Do Not use evaporation at all. Our vest only uses PCM (phase change material technologies), keeping people dry, comfortable, and able to work on those hot, humid summer days. We cool the skin, and blood flows past the cool skin and becomes cooler. It then travels to other parts of the body, keeping your core cooler while working with the different parts of your body that continue to sweat. Our pack can only absorb a finite amount of heat. But the beauty of our packs is having the ability to re-freeze below 70 degrees F or 21C. So recharge them in 30 minutes in ice water.
Putting it all together
In summary, cooling vests can reduce sweating by aiding heat removal, but rarely eliminate the need for sweating altogether. The body's natural thermoregulation will continue functioning as needed to prevent overheating. Remember that a cooling vest supramentally cools your body, not for environmental cooling. The longer you prevent overheating, the less fatigue, the better performance, and, most importantly, the more safety.