I got some cozy Smart Wool armwarmers that I love, plus I have some nice cotton stretchy ones, but I needed/wanted some for running. Well, they cost a fortune, so I figured, why not make some to test out the waters? I haven’t worn these running yet, but I think they will work okay. They are super easy to make (it’s just a tube), and you do not need a serger (just make your straight stitch length longer and/or use the zigzag stitch).
I have puny arms, so if you decide to make these, you might want to add an extra 1/2″ or so. Cut out a pattern where the upper arm is about 8.75″ wide (that includes a 1/4″ seam allowance) and the wrist about 6.25″ and length about 15.5″. Just take a ruler and draw a line from the width of the upper arm to the wrist (does that make any sense? I can add more pictures if anyone is interested). Form a tube with right sides together and sew down the long end. IF you are going to use these for running or for an activity that requires a lot of vigorous arm movements, I would advise using elastic in the upper arm region. I used 3/4″ elastic and formed a tube just slightly smaller than the fabric. Sew the elastic to the inside of the tube then fold the fabric and elastic down to cover the elastic and stitch. Fold up at the fabric at the wrist and hem, and voila! Arm warmers.
I used a nylon lycra, but if you have an aversion to synthetics, you can certainly use cotton lycra or whatever. Just don’t come crying to me when your armwarmers get all wet with sweat and you have no wicking abilities.