Hello Heba

Jmat is right. Don't buy any current video consoles to get fit. I dare to say you will get the opposite effect. Just get outside more, maybe try easy workouts with Endomondo tracker, if you really like new technologies. Riding on your bike or running  with Gps can be rally fun. You can share your workouts, beat your personal records etc. Some people use Fitbit to be more concious about calories, quality of sleep, activity levels...

Generation ago Nintendo Wii would be a good choice for active sport games. Not any more though. 

I have a Nindendo XL that was given to me for my 51st birthday and it is still going strong despite being dropped on the floor a number of times.

I like to play Scrabble and all the jewel games and Iove it !   It is light, easy to carry around, easy to use in bed as the light from it is quite bright.

I also have the 3D one, but it is in the drawer, I never use it, I don't like it.

If your goal is to get fit I think you'd be better off buying a squash or tennis racquet :-D

People talk about differences in graphics and RAM between the different consoles, but honestly for me these differences are two minor to even bother. The deciding factor for me (apart from price) is which console exclusives each console has. If you're interested in games like Forza, Halo and Gears of War, you might want to choose an Xbox. If games like Ratchet and Clank, Uncharted and Until Dawn appeal to you more, then a Playstation might be the thing for you. 

I decade ago I would have recommended the Playstation 2 because it had some amazing 3D platformers (Ratchet and Clank, Jak and Daxter, Sly Cooper and Ape Escape), whereas the Xbox only really had Halo. I'm not nearly as big of a gamer as I was back then, so unfortunately I don't know what to recommend now. 

PlayStation 4

great graphic, a lot of games , many languages , and more popular