Of course, the kids needs should always be prioritized, but still ... anyone that has taken an airplane has probably heard ...

In case of a loss of cabin pressure, oxygen masks above your seat will deploy, please place the mask first and then assist your child or other passengers

The rationale is very simple, if you pass out due to lack of oxygen, you won't be able to help neither the children, yourself nor the neighbour. General fitness is another thing, but if one doesn't take care of personal health, one may end up not being able to take proper care of the children either.

I had more than one year with really bad back pains (herniated disk). For most of the period I couldn't sit for more than some few minutes (meaning that driving a car, biking, sitting by the laptop, taking an airplane, going to a theatre or cinema was pretty much out ... and it could be awkward at meetings, when visiting people, dining, etc), lifting kids was not advised at all, but hard to avoid sometimes. At the very worse it was painful both to sit, walk, lie and stand ... almost all I could do was swimming. When it comes to work and money, social security standards are quite good here in Norway, I had a partial sick leave but got paid 100%. However, being a good father and do even simple things as taking my daughter to the kinder garden ... and then aiding her to change clothes after arriving there ... that was a bit challenge!