Complex sentence: Having a higher oxygen fraction in the lungs serves no purpose, and may actually be detcal profession warns that individuals with respiratory diseases such as asthma and emphysema should not inhale too much oxygen.
Split into simpler sentences: Having a higher oxygen fraction in the lungs serves no purpose, and may actually be detrimental. The medical profession warns that individuals with respiratory diseases such as asthma and emphysema should not inhale too much oxygen.