[xarope]

Do you have any medical conditions?

Assuming you've had yourself checked up, and do not have any medical conditions, then maybe you are just aerobically deficient (https://uphillathlete.com/aerobic-training/aerobic-deficienc...). Start slower, doesn't matter if you are walking. In fact, if you are doing 3x45 mins of zone 2 each week, start doing 2x45mins of brisk walking to keep your heart rate at zone 2. After about 4-6 weeks, you should find that you can start jogging again and hopefully (!) your heart rate doesn't peak so fast.

(I'm assuming a lot of things here, namely that you know what your LT1/LT2 are so that you can accurately calculate your 5 zones; https://www.trainingpeaks.com/learn/articles/joe-friel-s-qui...)