For many of us, sedentary jobs and lifestyle make it a necessity for us to exercise intentionally, always looking for ways to squeak a work out into our day. When the demands of the new lifestyle require everyone to engage in physical activity all day for some of even our most basic needs, then that will be more than a daily work out. If we weren't already in shape, we will get shaped up pretty quick!
However, depending on individual needs, additional training would be beneficial- whether to be able to perform a task better, or to balance out by performing exercises that aren't worked in the day to day tasks. As mentioned, food might be scarce. If it is, then choices need to be made based on that. In summation, if there is enough recovery water and nutrients to warrant it, then proceed with exercise.