Genetics but the good news is... there is 60% chance possibility you can. Takes hard work.

You have to get used to it. How?
Train 300 watts. How?
Intervals... shoot for 1 min 300 watts or close to it,
Keep doing it 12x in per training... you can relax 1 min or if it is too hard try relaxing when HR hit 154, and then go again.

After you do this, you can up the power for 310 or so or.... hold it for 300 wartts longer, maybe1.5 min, then maybe after a week hold it for 2 min... then keep going...

You can do it. The key is adapting your body to the situation you need to gain.

Also don't forget to rest your Heart... your heart gets tired as well from pumping high HR and so as your legs.. train smart.

You are not gaining as much or close to nothing when you can't lift up your HR to 160+.. It differs to people. Mine is 164 to gain progress.

Also some people do it easily because they have low resting HR..and their muscle growth is better. means their heart is stronger than ours. This means we have to work harder

Good luck.