I had pneumonia quite badly 2.5 years ago. I still am not as robust as I was. I improved but then it returned and left me with a lot of fluid on the lungs. I was very wheezy and put it down to being unfit but I couldnt read aloud or sing in assembly - I am a teacher- let alone get back to anything like my normal running and it turned out that I had developed asthma most likely as a result of the infection. So make sure you monitor if it is natural 'unfitness' which improves with training and if not go back to the docs.
I am back running regularly but am better at distance than speed not that I was ever a great runner more of a regular plodder.
Peter, read again, the point I made is skivers are in both private and public sectors, however they are easier to handle and get rid of in the private, whether that is because of strong unions or lax management. Also if your wife brings work home she needs time management, it's not necessary.
Anyone who regularly brings work home needs an assistant, not better time management.
I don't suppose that applies to teachers who already work 7 30 to 5 30 then bring marking, report writing, special need assessment reports etc home. Of course not as teachers are lazy overpaid skivers who are easy to criticise but few people are willing to give up their own, far more difficult, careers to improve the lot of the next generation.