my two cents: Background, am an old now, 57, and the last time I ran long distance was 2010. The Tyler Half-Marathon beckoned. Their website had the best tag line ever: "Where will you be on 10-10-10? So I registered, trained with the old Tues, Thurs. Sat. running plan. Those long runs on Saturday were very peaceful, cleared my head. Training included a 15k in Sherman along the way.
Had allergy issue day of Tyler race, and vividly remember those bricks in Tyler. I trained for probably 6 months for the race and my weight never went down. I was about 237 day of race. 5'11".
Except for getting water during the water stations, I ran the entire way until completing mile 10. Then my field of vision started to narrow. I ran/walked the remainder. Finished a nice slow 2:53.
Fast forward to March 2022. I'm in northern rural Alaska, no fast food since December, and am losing weight, partially due to staying active playing pickleball and partially due to having to eat my own cooking. Pickleball can sometimes get to 1.5 hours or so. Nearly addicting.
A fellow teacher gets on the PA and announces the bridge races are to be held later that day. The races under the bridge are on the frozen river, and are in age groups. I'm in the 56-58 old man group.
The race is to the ATV and back to the starting line, maybe 50 yards. In a photo-finish I win! One spectator yelled "tie!" as we finished, but they gave me the envelope with the winnings, $30, woohoo!
Another round of races was supposed to happen in late April, but the weather warmed up, so I am the reigning bridge race champ- 56-58 year old division.
Bottom line, you may not need any training. You definitely need to stay active. I am in Texas visiting this summer, and weighed in at the dr. office at 216 on May 17, down from 240 in summer of 2020.