Extracted from the ARRL letter. This is especially pertinent to those of us that climb towers.
WORD TO THE WISE
A fall is a common reason for a trip to the Emergency Room for older adults, usually male, when they look up, feel faint, then pass out when working on a ladder or on a tower. The usual cause is restricting blood flow in the arteries at the base of the brain when tipping one’s head back. It seems to be a condition that becomes more pronounced with age. You can test this fairly easily: stand straight and tall – then tip your head back as far as it will go without bending your back. A few seconds of readjustment before you get your equilibrium back is more or less normal. If dizziness persists or gets worse, you have a problem to have checked out by your doctor. It is better to find this out at ground level than aloft, don’t you think? From the ARRL letter September 23, 2014