Running underwear will be close-fitting and breathable.
It is important to choose garments that do not have bulky or excessive seams that can cause discomfort during running, and the running underwear will need to be lightweight. One of the primary goals of such underwear is to keep the user dry and comfortable during all conditions, so synthetic materials are often used to make the underwear; this material is breathable, lightweight, and durable. Be sure to do a bit of research to find out common prices for such running underwear so you know what to expect when you go shopping.
Moisture-wicking running underwear will help keep moisture from building up on the skin.
The sweat and moisture on the skin will be pulled away through the fabric, allowing the skin to stay cool and dry. In colder weather, this breathable type of running underwear will help the body retain heat as well. Choose breathable underwear that is lightweight and comfortable. The materials used for such underwear may include Lycra®, polypropylene, or certain types of polyester. The prices will vary according to the materials and design, so be sure to do some research to find out which material will work best for you.
Seams can be problematic on running underwear, though they are in most cases necessary to provide a tight fit. Be sure the seams are not in places that will lead to chafing during running. The seams should be strong, but if they are overbuilt, they can end up irritating the skin during repetitive movements. Inspect the running underwear to find out where the seams will end up being positioned on your body and try to make a determination as to whether they will end up irritating your skin. Pay attention to the waistband as well, as this is a common source of irritation. The band should be tight-fitting, but the materials should be soft enough that skin irritation will not occur.
Air should be able to reach the body through the running underwear to help keep the skin cool and dry. Thin materials such as Lycra®, spandex, and polyester can allow this to happen. Air flow will help prevent sweat build-up that can otherwise lead to irritation. Lighter weight garments will have less of a tendency to bunch up during repetitive movements as well, meaning the runner will remain cool, dry, and comfortable throughout the period of running.