Plan an athletic activity
If you are overwhelmed by a big city and do not enough time, plan an athletic activity to take in the sights. Look for a bike tour or walk tour of your destination. Some cities even have free tours.
Pack snacks / plan ahead
It's easy to fall off of your eating plan when the only thing available are junk food. While you can't plan ahead for every meal, you can bring some healthy snacks to help you in times of need.
Use Your Hotel Room
Hotel rooms offer space and sometimes some equipment! Try doing dips on the bathtub, decline push-ups with your feet on the bed, or squats while holding an iron.
Pack Equipment
If you bring it with you in your suitcase, there is a good chance you'll use it! Pack some resistance bands with you. They're lightweight and don't take up much room. You can use them on the plane, in the airport, or in your hotel room.
Walk to Dinner
You can walk to dinner or anywhere else you want to go. It's easy to hop in a cab, but if you walk to your destination, you'll be kind to your body and your wallet. Just ensure you find out about the place you are walking to and if it is not safe, just stay back in your hotel.
Use the hotel gym
Quite a number of hotels now have gyms. Although this may add to your overall cost, it is worthwhile if you are really passionate about keeping fit during your vacation.