Then there was Thatcher.

interestingly - I have read in the New Scientist and on radio documentaries that: sleeping less that the normal (for normal humans) 7½ / 8 hours per night brings with it a higher risk of Alzheimer's, later in life.

4 hours (reputedly) and those later years.

Just saying.

Scuse me while I take a power nap, I only got 7 hours last night.