If you’re not used to exercising, then even exercising at 60% of VO2max represents an overload.
If you’re used to exercising at 60% of VO2max, then you need to exercise at (say) 70% of VO2max to create an overload.
If you’re used to exercising at 70% of VO2max, then you need to exercise at 80% of VO2max to create an overload.
If you’re used to exercising at 80% of VO2max, then you need to exercise at 90% of VO2max to create an overload.
If you’re used to exercising at 90% of VO2max, then you need to exercise at 100% of VO2max to create an overload.
So, how fit are you (and how badly do you want to improve)?