Language is shaped by many different influences. Over time, certain phrases become part of the vernacular and are spoken to signify how one acts or feels, including phrases about health and well-being.

Some phrases may inspire curiosity as to their origins. The following health-related phrases have some interesting backstories.

‘Fit as a Fiddle’

The phrase ‘fit as a fiddle’ is often used to describe someone who is very healthy and full of energy. But what does fitness have to do with an instrument, anyway? Actually, very little. According to The Phrase Finder, ‘fit’ didn’t originally mean healthy. It was actually used to represent the words ‘suitable and seemly.’ Therefore, something that is fit as a fiddle would mean it was suitable for its purpose. Now ‘fit’ frequently refers to one’s physical shape, and the phrase has evolved.

‘Survival of the fittest’

Again, the word ‘fittest’ initially did not represent physical strength or well-being. Rather, in this phrase, attributed to Herbert Spencer and later to Charles Darwin, fittest referred to those who were best suited to their environment, or more plainly, those who were best able to survive. Today, it can mean anyone who is able to rise above the odds against them or beat the competition.

‘Strong as an ox’

The idiom ‘strong as an ox’ has long represented a person who is unusually strong and able to persevere. Because oxen are large beasts of burden that were used instead of horses by American settlers before railroads were created, anyone compared to an ox would have to be someone capable of strong physical labor and ability.

‘An apple a day keeps the doctor away’

Many believe this phrase to be a helpful rhyming device to remember to eat healthy food to maintain good physical health. However, according to Snopes, the first known version of this proverb comes from Wales in 1866 and stated, ‘eat an apple on going to bed, and you’ll keep the doctor from earning his bread.’ Other sources trace the phrase to ancient Rome. Apples can have many health benefits, but no research has confirmed that eating an apple daily will safeguard individuals from any particular illness. A 2015 study published in JAMA Internal Medicine did find that people who ate an apple required fewer prescription medications than those who did not.