Running apparel can be loose or tight. It's really a personal choice, but in many summer styles are not members, in order to cool the runner easily. In winter clothes tend to be narrow (at least the clothes on the skin) to maintain body heat. Make sure all running clothes that you buy does not rub or cause friction, which can lead to irritation.
Reflective fabric is another great innovation in the management of clothing. It's great for people who rush out at any time of day or night. When the light hits it, it has a reflective quality that makes you visible to motorists and pedestrians.