When I book a hotel, the first thing I look for is a gym.
I refuse to book a hotel unless there is some form of fitness center. I work out everyday, regardless of being on vacation. I have learned in my vast booking experience that every gym is different. The hotel words the gym different to show a distinction. If the hotel says they have a gym, this usually means a small room. The room has a few treadmills, an elliptical, hand weights and a few yoga mats. It is the bare bones of fitness equipment, but is doable for me. If the hotel says they have a fitness center, I know I am going to be spoiled. I usually can expect to sit down and stand up bikes. There are also machines for weight lifting like a pull down bar. There are way more hand weights and more space to put the provided yoga mat. I have also booked hotels that say they have a health and wellness center. This is usually more of a spa like situation. There is steam baths, saunas and hot tubs. Sometimes you can get a massage at the health club. For fitness, there might be pilates or yoga classes offered. I usually can find a wide open room with only yoga mats in it. That is fine though, I can do a whole work out with no equipment and just lots of space. I am willing to take any fitness equipment and situation thrown at me. I am not too picky as long as there is something.