Ready for some Friday R&R? Catch up on the latest and Greatist in fitness, health, and happiness with our weekly roundup of our most popular articles this week:

Illustration by Shannon Orcutt

The Ultimate Guide to Running Lingo

Everyone know runners are a little, well, different. So it’s no surprise they have a language all their own. Read on to learn the difference between a PR and a BQ, and just what the heck a fartlek is!

Do Juice Cleanses Really Work?

It’s impossible to make the healthiest choices all the time and “detoxing” the body with all sorts of cleanses has become a popular way to try correcting those bad choices. But are they really effective— or safe?

Can Being Bitter Make You Sick?

Stop blaming everything on that horrible ex. Research suggests bitterness isn’t just about pouting— holding grudges can make us physically sick.