Thousands of videos on social media are suggesting that people change their workouts depending on where they are in their menstrual cycles - something known as "cycle-syncing". These workout plans have surged in popularity online, with searches for the term rising 740% since 2022 and more than 55,000 TikTok videos now using the #cyclesyncing hashtag. Most of the advice is shared by fitness and wellness creators rather than medical or research experts. One researcher, who specialises in menstrual cycles and exercise, told the BBC there is evidence that some women experience changes in symptoms, energy or perceived strength across their cycle - but that is different from saying all women should train in a particular way at a particular point. Tap the link in @BBCNews's article to read what fitness influencers think. #WomensHealth #Period #MentrualCycle #Gym #BBCNews