I bike in the summer, but I run at the gym all winter and hope to keep running for more years. As someone said, there is a high you get from it once you establish a routine. The key is a routine that doesn’t lead to pain/injury. For me, at 69, it’s 3-5 miles three days a week. I do weights or elliptical and stationary bike the other days. Beyond the cardio benefits, there’s research on the effect of running on brain health. My dad died from Alzheimer’s and I want to give myself every chance of avoiding that. I have friends who swim, which is great, but I don’t think that’s my thing. I tell them “swimming is boring - I run on a treadmill!”