According to Official Guinness Records,
The largest hula hoop workout consisted of 537 people and was achieved by Dottie Woods (UK) in Romsey, UK, on 15 October 2017.The attempt took place at "The Great Hooping for Happiness" which was organised to raise the profile of MacMillan Cancer Support.
For a complete list of 2017 records, please visit 2017 Guinness Records in United Kingdom.