Why is Thermal Underwear Warm?

With thermal underwear for women being so thin, you may be asking why it’s so warm to wear. Whether you are rocking a full set of thermals or just women's thermal pants, their warmth is the primary draw for many people during lower temperatures or when visiting colder climates. Even though they are lightweight and thin, thermals provide a lot of heat retention abilities. 

How Thermals Keep You Warm

You lose body heat in many different ways. Your body heat can be transferred from you to a colder object called conduction. An example is sitting on a metal bleacher stand at a sports game, and it feels like your body heat has been sucked from your body. The other method is convection is when you lose body heat through a liquid or gas. You can experience this by a windy day or even diving in a pool. Thermals work as insulators. Due to their snug fit, they keep air close to the skin for better distribution. That way, when it gets windy or your sweat, your body heat isn’t lost, and you stay warm. 

Though thermal underwear for women provides a base layer of insulation, its main job is to fight off evaporative cooling. Try blowing against the skin on your arm. Do it again, but first lick that area or moisten it with a towel. The wet feels cooler. As moisture evaporates, it takes energy away from your skin. Women’s thermal pants keep you warm by drawing the sweat or moisture away to minimize this effect and keep you warm longer. This also reduces the chance of you getting frostbite or hypothermia as they keep you dry. 

How a Thermal Keeps You Warm is Dependent on its Material

Not all thermals are made the same. Material like cotton, though comfortable, absorbs moisture and sweat, which can create problems when you’re trying to enjoy the outdoors. By trapping that wetness against your skin, you get cold faster and also have to deal with the dampness and sogginess that comes with the material.

Wool and synthetic are ideal as moisture-wicking and keeping your dry. Staying dry is imperative to staying warm. Thermals made of these materials are often durable and long-lasting, not to mention they fit like a second skin to trap heat in and keep you warm by pulling sweat from your body and releasing it. 

Silk also offers these benefits with some added luxury and cost. The downside is they aren’t very durable, so it is best to stick with a polyester/spandex blend at an affordable price or invest in a Merino wool thermal set. 

Thermals are uniquely designed to keep you warm. They do this through the material, moisture-wicking features, and overall design and fit. They work with your body to regulate body temperature so you don’t overheat so you can freely wear them for sports or other athletic activities.