How Do Cooling Shirts Work?

Most men know that Summertime is synonymous with “sweating bullets.” Most shirts don’t stand a chance against a man with sweat glands capable of dwarfing the magnitude of the Niagara Falls. This is why, if you’re anything like what was just described, you need cooling shirts and UV blocking shirts in your life ... like a lot of them. Cooling shirts and sun protective clothing might sound like a magical gift, but there’s actually a lot of science that goes into their ability to wick away moisture, have optimal breathability, block harmful UV rays, and keep you active outside longer.

Let's talk about cooling shirts and the frequently asked questions around the fabric technology:

  1. How do cooling shirts work?
  2. What types of shirts and fabric keeps you the coolest?
  3. What is moisture wicking?
  4. How do fabrics stay cool?
  5. What fabric blocks the most UV rays?
  6. What is Ultraviolet Protection Factor (UPF)?

Man in MuskOx Outdoor Apparel Cooling Shirt that is UV Blocking Photo of man wearing a MuskOx Ultra Lightweight Charleston Sun Hoodie

How do cooling shirts work?

The theory overall is to try and get warm water and sweat away from the body as soon as possible once you get hot. Once warmed, the layer of air surrounding your body reduces the flow of heat out of the body -- which limits your ability to cool off fast. Fabrics that have high breathability matter. Synthetic fibers that are cool to the touch, block harmful UV rays, and dry fast are the best at regulating your body temperature. If you were naked (we’re glad you’re not), the warm air would drift away from your body via convection. Cooler air would move in to take its place. That new air would now pick up more body heat and carry it away, too. The same thinking applies to sweat as well so let’s get into how this can be addressed with intelligent cooling fabrics and what exactly goes into our thoughtfully designed performance summer shirts and cooling fabrics.

What types of shirts and fabric keeps you the coolest?

Synthetic fabrics allow the most body heat and moisture to be released and escape the fabric. feel considerably cooler when the temperature rises. The temperature of the physical fabric is also cooler to the touch than natural fibers, providing the body a cooling sensation. Synthetic fabrics also allow for high airflow when moisture is trapped in the fibers. The airflow then evaporates and drys the fabric which cools skin and reduces the weight of the shirt.

Compared to cotton, synthetic fabrics make better cooling shirts because they dry faster, weight less, and since they have a tighter fiber weave they do a better job at blocking harmful UV rays from your skin.

What is moisture wicking?

Polyester is a synthetic fabric that is most commonly used for moisture wicking clothing. This is a synthetic fabric that is lightweight, durable, and inexpensive. A lot of workout clothing is made out of polyester, but the key is the properties of the fibers and creating sufficient micro “voids” that allow for cooling to occur, in addition to having the fabric connected in an intelligent way to disperse heat and sweat.

The rumors are true: we have fantastic cooling shirts at MuskOx Outdoor Apparel. As much as we all love just getting out and enjoying the adventure, we want you to rest assured that when you're outside your clothes won't be slowing you down.

Our shirts, and any good cooling fabric, is designed for moisture wicking (get the sweat away from your body), moisture transportation (make it easy for the sweat to spread out to maximize transpiration rates), and regulated evaporation (depending on your body temperature, regulate the rate at which sweat comes off the fabric).

Man resting after run in MuskOx Outdoor Apparel Performance Foundation Crew Base LayerPhoto of man wearing a MuskOx Performance Foundation Crew Base Layer

How do fabrics stay cool?

The key to keeping a cool touch is having cooling technology built into the individual fabrics fibers that make up the clothes. This maximizes the cooling properties of the fabric and decreases the extent to which human body temperature rises when clothing is added to the body.

Cool touch design also contains moisture wicking properties by drawing sweat away from your body, and into and out of your clothing. This is great to wear in direct contact with your skin, so that you can get the full effect of this moisture wicking magic. We designed our Performance Foundation Crew as a super breathable and quick drying base layer for outdoor activity and exercise, meant to be worn independently of other internal layers. The base layer is also antibacterial, so when it does trap in moisture and then dries, odor cause from sweat is not left behind.

What fabric blocks the most UV rays?

One of the most important aspects of a summer shirt is its ability to block harmful UV rays. UV rays can be harmful for the body & we want to minimize exposure to sunlight when we’re trying to stay cool for long periods of time. UV rays can penetrate a lot of day to day fabrics, but intelligently designed synthetics can keep the sun out. A lightweight, UV blocking synthetic shirt is a great choice for any day in the sun -- whether that’s on the water, at the beach, or out in the wild.

What is Ultraviolet Protection Factor (UPF)?

Synthetic fabrics typically have a higher Ultraviolet Protection Factor (UPF) rating than cotton because of the tightness of fiber weave. The Skin Cancer Foundation recommends wearing fabrics with at least a UPF rating of 30+ for your clothes to be considered sun protective. Cotton fabric typically has a 5 UPF rating. Our MuskOx performance cooling shirts have a rating of 30+ (very good), these synthetic fabrics are breathable but have a denser weave that protects against the sunlight. This allows for less UV radiation to reach your skin, therefore making it a safe option to wear out in the sunlight.

Darker colors have a higher UPF rating than lighter colors or pastels. Although it is true that lighter colors attract less heat, darker colors are best when protecting against UV rays.

Three cooling shirts by MuskOx Outdoor Apparel to test this summer

Photo of man wearing MuskOx Charleston Performance Sun Hoodie

Charleston Performance Hoodie

This UV blocking and moisture wicking sun hoodie is constructed with technical, lightweight knit fabric blend that keeps you 14% cooler than comparable synthetic fiber. It's constructed with thumbholes and chest pocket with a bungee sunglasses loop.

$72 - SHOP NOW


Photo of man in Ultra Lightweight Charleston Performance Hoodie

Ultra Lightweight Charleston Performance Hoodie

The Ultra Lightweight Charleston Performance Hoodie is our lightest sun shirt that's paper-thin, comfortable, and ready for a day of high heat. Its technical UV-blocking fabric wicks moisture away, dries quickly, and keeps your body temperature cool.It's constructed with thumbholes and chest pocket with a bungee sunglasses loop.

$72 - SHOP NOW


Image of MuskOx Performance Foundation Crew

Performance Foundation Crew

Get after your workout or cut through the heat in the Performance Foundation Crew, a lightweight performance shirt with two tone performance finishes that allow maximum airflow and sweat wicking. This baselayer is antibacterial, reducing sweat causing odor.

$54 - SHOP NOW