Before a race a mylar blanket a.k.a. heat sheet, is a must have. It is cheap, disposable, and easy to bring with you to the starting area. I save old ones from races and bring to the next race, but the ones you can buy on Amazon are folded up so small they are perfect to tuck in your runners pouch, suitcase, even glove compartment. I swear by these and highly recommend them. Click here to be taken to the Amazon link.