09/11/2026
90–100% of max heart rate. Welcome to the redline. 😂
Do you need to train here? For most people, **absolutely not**. You can build excellent cardiovascular fitness without constantly pushing yourself to your maximum.
But there is some cool physiology happening.
As exercise intensity increases, **heart rate increases and stroke volume—the amount of blood your heart pumps with each beat—initially increases too.**
In many untrained or moderately trained people, stroke volume eventually **levels off at submaximal intensities**, while heart rate continues climbing. But that plateau isn't universal. In well-trained endurance athletes, stroke volume can continue increasing all the way toward maximal exercise.
That means at very high intensities, increases in **cardiac output = heart rate × stroke volume** are increasingly driven by that rapidly rising heart rate.
So why am I hitting 90–100%?
Not because everyone needs to.
I do it because I still can, I enjoy testing the engine once in a while, and yes…apparently I enjoy a little pain. 😂
Train hard. Train smart. You don't have to redline every workout to build a strong heart.
