I had a long (marathon) training run on my own and the weather turned out to be varied and my arms got pretty cold at times but I didn't need to add another layer. Researched these, purchased and works on next training run. same situation. These were perfect. easy to put on and off. Super comfy and did the exact thing they are supposed to do. also really useful to pull up if you are wearing a Tee and need to put a rain jacket on as they help stop sweat getting inside the jacket. This also happened not he run.