A fascinating thread, particularly as I’m now in my fifties as well.Like Wils1234, I always maintained a certain level of fitness but in my mid-thirties to mid-forties, I was overtaken by a poor diet. I still ran and just managed to still claw a sub 50 minute 10K and a sub 2 hour half marathon in 2006/07 but after that I thought it would just be a case of maintaining a fitness level.I hope what happened is that I had my midlife crisis in 2010 where I lost weight (95kg to 75kg) and improved my fitness such that I was able to churn out sub 45 10k’s and achieve PB’s at half marathon. I would say that now I am quite possibly the fittest I have ever been since my mid-twenties.I think two elements of my midlife crisis were money and career but I knew I could do something about fitness and now I have that back again, the other two don’t seem quite as important.But I have also learnt not to overdo things. So I ignore those adverts in the back of the Metro for trekking expeditions up various mountains etc. I am quite content to be running two to three times a week from a 5K Parkrun, to 10 miles or half marathon distance several times a month. Absolutely love it and look forward to it, especially with the GPS gizmos which is just amazing technology. Mostly just racing against myself.As Wils1234 has pointed out, though I did do London twice, I have no desire to run in a marathon with tens of thousands ever again. Kudos to those who do it but I’m not going through several layers of hell just to get to the finish line. I am thinking of doing a lower key one next year as suggested by didds2 but I will need to see if I can fuel as I go and will probably try the distance out myself first. If I hit the wall (or anything else) then I will drop out. So definitely no sponsors as I don’t want to feel compelled to finish.Though I do find it sad that many of my peers, barring unexpected events, are falling by the wayside (or worse) as they seem to see being in their fifties as some sort of barrier to fitness or getting in the way of other goals such as career. What’s even worse is seeing a self-destruction culture of wine drinking and rich food at what seems to be an ever increasing number of dinners and awards ceremonies which may look good on publicity but not for waistlines!