Oh yes it is! At least according to a leaflet sponsored by TfL [1].

Medicine? Rest? Recovery? Pah - they're for wimps! A hard day's graft is what you sickly types need.

The leaflet encourages us to reject common 'myths' about ill-health including such fictions as: illness can be cured by medical treatment; you should take sick leave if you are sick; and a sick note means you should stay off work.

Unsurprisingly, this leaflet appears not to be endorsed by any authoritative medical body. Just by a bunch of employers and insurance companies. And by the Health & Safety Executive. Which shows how concerned for your health and safety they really are.

Perhaps they should read some of these facts [2] to remind themselves that work is not alwasy good for your health.