Yesterday I did an hour and a half ride in what I think is cold weather. Sunny, light breeze and 18 degrees F. To help keep my feet warm I used chemical heat insoles. I opened the package, activated them to warm and placed them in Sidi mesh shoes, used wool socks and neoprene booties. Feet were comfortable for about 30 min. and somewhat chilly for the rest of the ride. When I got home the insoles were cold. The package said that they are good for up to 5 hrs. What did I do wrong?