Both Kyla and Tia will be in their zone. Even if they dicrease their heart rates by 20 beats per minute from 175 beats per minute. 155 beats per minute still falls under kyla's target heart rate zone and Tia's target heart rate zone.
I agree with the speaker that the ability to learn is not fixed and can change with your effort because the more you persevere to know, the more knowledge you will gain and acquire. Moreover, the more we sharpen our brain, it will get more information that we need and we can use it in our way of life especially in our decision-making.