I get this question frequently: I need to travel, will I lose my fitness??!?!
Don't feel like you'll lose fitness when taking a week off. A vacation can be the perfect time to let your body heal completely and you will be fresh to continue your training when you return. For many, I suggest to take a week out ten off as a good schedule to keep to prevent overtraining.
The active vacation: If you exercise regularly and you're headed out for an active vacation, like skiing, rafting, mountain climbing, this is the perfect time to USE the fitness you've gained from your normal training. That's the 'sport/specialty' on top of the fitness pyramid! If you've been good about the rest of the pyramid, you'll be surprised how good you are at many things that are NEW to you. This is because you've been hitting many points of fitness simultaneously (both in terms of movements and metabolic pathways). Training outside your comfort zone prepares you for activities outside of your comfort zone, it's that simple! Of course you should go out and enjoy your new fitness gains in creative ways.
In travelling for work or over the holidays if you are afraid you're losing fitness; here's a list of exercises that can be done at most hotel gyms. Link: Bodyweight Workout List. This list varies from no equipment to needing a pullup bar, rings, or a jump rope. If you find that you make the same trips periodically, (for example, the annual Consumer Electronics Show or a quarterly training event) record which workouts/performance and repeat them every trip to track your fitness gains.
How do you workout (or choose a running path) in/near a hotel room?