schwinn quality bike LISS Cardio
https://www.scribd.com/document/426386813/198190LISS-Cardio-Explained-in-Fewer-than-140-Characters
Even the best stationary bikes LISS cardio are less bulky compared to a treadmill or even a crosstrainer, also so you'd swerve the travel to and out of the gymnasium (time-efficient for all those with hectic schedules)