If you answered NO to all the PAR-Q questions, you can be reasonably sure that you can exercise safely and have a low risk of having any medical complications from exercise.
It is still important to start slowing and increase gradually. It may also be helpful to have a fitness assessment with a personal trainer or coach in order to determine where to begin.
When to delay the start of an exercise program:
If you are not feeling well because of a temporary illness, such as a cold or a fever, wait until you feel better to begin exercising.
If you are or may be pregnant, talk with your doctor before you start becoming more active.
Keep in mind, that if your health changes, so that you then answer "YES" to any of the above questions, tell your fitness or health professional, and ask whether you should change your physical activity plan.