Yury,
Yes, this is complicated. It’s important to understand that while marathon and Ironman are similar, they are two very different sports. There is a reason there are no professional cross-over athletes. You can be good at both, you can only be great at one at a time.
Training for an IM and a Marathon at the same time is like trying to make something both a pizza and a cake at the same time. You can bake one or the other.
The best decision is to split them up by at least 12 weeks and train for them separately. If you must include a marathon as part of Ironman training:
– Replace your shortest cycling workout with a run and follow the workout as a run
– Add a run of 60-90 minutes each week, all Zone 1-2
– Increase your longest run each week by 30 minutes, but no longer than 3 hours
We do offer a custom plan service that can help with this, see https://www.8020endurance.com/custom-plans-and-coaching/
David