Men and women who like continuous shiftwork are more 'hardy': But what does it mean?

Continuous shiftworkers of both genders who like shiftwork and report fewer digestive problems have higher scores on hardiness than those who dislike shiftwork. Whether this is a causal, consequential or accidental relationship requires a longitudinal investigation. It is also not clear how far 'hardiness' is a personality measure, a behavioural style, a coping strategy, or a consequence of the stress of shiftwork.