Sorry to be late to the party, been down with the flu. Bring fresh undies and socks to the office. As you get in shape, the faster your body returns to a resting heart rate, the faster you will cool off. Ditto easy on the ride in. Ride harder on the way home. If you must ride with a backpack, buy one much bigger than you need. A loosely packed bag is more comfortable than a fully stuffed smaller bag.