Modern technology has provided us with many time saving devices but

At the cost of the well being of the patients. Companies are inventing a lot of machines at a fast pace and it’s really hard to test if they are safe.

Its simple its a because they are more fat

Because without physical activity, the body has extra "energy" if you will, and so when it is time for bed you are not tired, so you end up staying up all night. also there is probably an effect on your internal clock, which messes with your melatonin production which goes hand in hand with your sleep cycle