They will be able to perform at optimum in their own latitude. Where they get into trouble is when people, born in the north, go south to compete, or vice-versa. They then run into a little known, but very important energy dynamic known as bio-energetics. Our US athletes are all born in the northern latitudes and now how to perform in southern latitudes. They are all under more stress than they realize and that can directly impact how well they compete in the Olympics.
Problems begin when someone born in the north goes south.
Consequently, the energy system is put under tremendous stress to change and adapt to this 'different' flowing energy. It is the adaptation time that can cause an athlete problems and not allow her or him to compete at optimum. Generally speaking, the younger the person, the faster they can adapt energetically to this new environment and latitude. Then, it can take up to 4 weeks. In an adult, the pulse is between 80-100 beats per minutes and this is considered normal.