Commercial or passenger aircraft are usually designed for optimum performance at their cruise speed or VC. Combustion engines have an optimum efficiency level for fuel consumption and power output. Generally, piston engines are most efficient between idle speed and 25% short of full throttle.
The blood to your head rushes when you do a quick movement, so, naturally, dizziness is expected. I think the blood rushes from your head too fast. it is called postural hypotension.. whereby, due to getting up suddenly to a upright position, there is lower blood supply to th head.
If you feel confused, wait for your mind to clear or until someone comes to help you before trying to get up and walk around. Some medications can increase a person's risk of falling because they cause side effects like dizziness or confusion. The more medications you take, the more likely you are to fall. Take the Right Steps to Prevent Falls. If you take care of your overall health, you may be able to lower your chances of falling.