I am 69, swim half a mile 3 times a week, and in better shape than our children. No plans to give up driving our RV for many years to come. In our vintage auto racing club in Colorado (Rocky Mountain Vintage Racing - www.RMVR.com), we have a couple of people still racing in their early 80's and many in their 60's and 70's.
Below is a link to a reaction time test you can take. For whatever reason, you will likely get better results using the keyboard than the mouse button:
www.justpark.com/creative/reaction-time-test/
Best regards,
Lowell