
Lockdown home fitness
It is perhaps belated, to really become more interested in fitness in your forties. However, I am genetically lucky (in some respects) in that I am inclined towards being very slim, elfin-like even — because I'm also not very tall.
My weight and size has stayed fairly constant: I am a mere 2kg heavier now than I was at 17. As I have got older, gaining weight seems slightly easier than before, but I am trying to be mindful of how much I put in my mouth versus how much energy I expend.
As of January 2021, the UK has been yoyoing in and out of COVID-19 restrictions for nearly a year, so our family has greatly minimised any time out of the house. We're no recluses, but I am just as happy staying at home, organising up a storm (only virtually, the place isn't exactly pristine), as I would be sitting in a café reading a book.

Prior to the first lockdown in March 2020, I had started running again. My habit was to drive to Coate Water and run a couple of laps. Then we locked down, and as I've recently explained to a friend, I can't just take my small humans with me and focus on a run, as they are feral and will go off in different directions.
Hence my home fitness project. Here are videos and workouts that I have been using, both in the past and present — past because I get bored easily, but they are kept here in case I want to go back to them.
Browsing for quick workouts (because doing virtual school with small humans involves so much more than just sitting them down in front of a computer) on Pinterest led me to a site called Darebee. They provide warm ups, workouts, fitness programmes, stretches, meal plans, and daily fitness challenges — all of which are released under Creative Commons.
Every weekday, if I haven't gone to bed too late the night before, I get up an hour before the small humans, wash up, grab a drink, and take some exercise. It sets me up for the day. I am definitely stronger than I used to be, though my push ups are still woeful.
An example of one of their workouts is on the left; go visit their site, use it, and donate to help keep them going.