But ummm P, what if one doesn't have that time? Sometimes, you only have that hour for gym and about 30 minutes to shower and get ready for work right?!?!
First off, park your car as far away as you can from the gym entrance, every little bit of physical movement helps, and preferably with direct sunlight to help heat up the inside of your car.
After your workout, get inside your car and don't roll down your window or turn on the ac, the heat built up inside your car while working out will give that sauna effect and will help extend that burning momentum and sweat out extra calories while driving from gym to home. Personally, I purposely miss that yellow light or take the longer route home just to extend my time inside the car or sit in my driveway for as long as I can to get that extra boost of sweat.