MAF training

I have abandoned my plan for a full marathon after almost 5 weeks of training after I came across this article about Maffetone method of training. MAF method suggests that you should not be running more than your MAF max aerobic heart rate which is 180 minus your age. After 2 months of following MAF method, I noticed a big difference in my fatigue level. I noticed that my fatigue level was high during May when I was doing a typical full marathon training and lower significantly on June when doing MAF.