14th August, 1978
My Dear John,
I see that you are still fixed in the idea that exercise, like fagging, is something that stops when one leaves school.  You are right that the precise value of exercise is the prevention of heart attacks, etc. has still to be rigorously demonstrated though there are some very suggestive studies.  There is a research programme on this at La Jolla and indeed I am part of their data!  It's true that it isn't likely to benefit you much unless you do it the right way.  That is, in their jargon, "aerobically" (which means you pant), gradually (in several senses) and fairly regularly.  Alas, the debilitating effects of life in England have already taken their toll and my fitness seems to have dramatically declined since I saw you last.  Incidentally, jogging isn't really a good solution.  It's apt to jar the spine, it's usually inconvenient to do and to most people it's boring.  I can recommend swimming, at least in the sunshine.  When the weather is poor, Odile quite likes bouncing about on a mini-trampoline, as it's a lot more fun than just running on the spot.  But all this, I can see, is unlikely to convert you.  Perhaps you had better try living in California!
As to R.V. Jones, by all means let's have a chat about this post-war situation but my recollections of that period are now so dim that I doubt if they are much use.
I enclose copies of two recent letters I have received (and my replies) which explain themselves.  I should have thought that EMBO might usefully be involved with one or both of these schemes but that I leave to you.
F.H.C. Crick