You’re no doubt familiar with high-intensity interval training (HIIT)—quick, intense bursts of exercise interspersed with short active-recovery periods—and its promise of amazing fitness benefits in a small amount of time. But how buzz-worthy is it? Here, Charlie Hoolihan, NASM-CES, PES, shares the good, the not so good, and some tips to help it work for clients at every level.

  • The positives: HIIT gets good results over a short period of time. There’s also evidence that it can improve cardiovascular fitness as well as—if not better than—traditional steady-state endurance training.
  • The HIIT downsides: Complex weight-lifting movements at maximum effort and in quick succession increase injury risk. Also, HIIT is often so intense that overtraining is an easy mistake. Evidence also suggests it’s an ineffective hypertrophy builder for those looking to maximize muscle size, and it has limited impact on explosive power. And finally, while it’s a great endurance training tool, long-distance athletes still have to put in longer efforts at least once every two weeks.

How can you make sure your clients are getting the best HIIT benefits? Here are Hoolihan’s tips.

  • Plan for periodization: Hoolihan says this is the same as with any good program: consider the goal (weight loss, performance, or both) and make long-term plans that include periods of progressive overload, recovery, and maintenance plateaus. If weights and cardio are part of the program, use one to support the other, depending on goals.
  • Tailor to individual ability: In the event that your client isn’t up to one of the exercises, be ready with some similar but easier moves. Also, give your clients permission to rest during the workout.
  • Stress rest: Even HIIT requires a long-term approach to training that includes ample rest and recovery.
  • Get a programming edge: HIIT’s intensity increases your clients’ injury risk. Trainers, especially those with CES or PES, have the advantage of knowing how to safely progress clients into complex exercises, and (with CES) they can scale exercises to account for clients’ muscle imbalances and misalignments.

National Academy of Sports Medicine