Clyde1820

Isn't a lot of time, on a bike. Getting heart-elevating cardio can be done rather efficiently in a gym or a stationary bike. Even a good brisk, even hard-driving, walk can be a good way to get that heart rate up over shorter distances.

If well under a mile (each way), you might consider walking that route. I'll bet you'll get quite a lot more cardio that way, simply due to taking longer. If done briskly, to a pace where continual talking is getting hard to do, it will be a decent amount of cardio on a 2mi walk, at least compared to that brief stint on a bike.

You could also consider getting a rucksack type of pack, whereby you'd walk with the sack weighted down with several pounds. A brisk walk with a rucksack can be noticeably more challenging, particularly if you've got any elevation changes to speak of along the routes you walk. And at under 2mi of distance overall, you ought to be able to cover that distance in a half hour or less.