I do rowing and weights a 2-3 times a week and so far it doesn’t have the same effect. I feel like it’s time + effort + heat and the non-bike workout are fairly short, ~30 minutes vs 4+ hours. I rode outside for about 3 hours yesterday at endurance pace and felt good during. Hydrated before and after (electrolytes the night before) and refueled and rested but about 3 hours after the ride, I was hit with a mild headache and nausea that lingered for the rest of the day despite pain relievers and hydration/electrolytes.
Good point on the journal. I will start keeping one.