At the Lublin Plaza, two minutes away from KUL, there is a gym called Jatomi Fitness. The staff speaks English. Here are the links to their Facebook page and website.
06:30 – 22:30
08:00 – 20:00
There is Aqua Lublin which is a sport complex including swimming pools, a skating rink, etc. This is the Aqua Lublin Facebook page and website.