Well, I certainly can relate a lot to your responsibilities! We raised 7 kids (the youngest is 16 now, oldest is 28, all from my belly), and, yes, we know "what causes that."
Did it on purpose. I get a lot of comments from younger mom's nowadays about what good shape I'm in, and I tell them that when I was busy with little kids, I felt good if I was fitting in 20 minutes of at home video workouts 3 x as week! But the physical activity was helpful for my overall well-being.
Also, I have been through nursing school. Graduated from UCLA in 1986. Used that knowledge to do a lot to take care of one daughter who died from leukemia a few years ago.
I do most of my biking on a spinning bike at home here. The hubby doesn't like me out on the road by myself cycling too much, plus the spinning bike IS convenient at all times of day and in any weather! Have a gym close for swimming.
I was an "immigrant of sorts" at one point, too, when we went to live in Taiwan for a while, so I know what it is like to adjust to a new country. Still trying to learn Chinese...
So, all that to say, I completely understand the constraints trying to get some exercise during real life! Keep up the good, balanced work and perspective. But don't forget to leave yourself margin.