HIIT versus LISS for fat loss

Posted on by Kristine Crump

 

HIIT versus LISS for maximum fat loss

There is a lot of literature out there comparing HIIT (high intensity interval training) to LISS (low intensity sustained state) training.  In this blog, I outline some key differences between the the two methods.

HIIT training involves short bursts of high intensity work alternating with short periods of working rest.  HIIT uses fast twitch muscle fibers, and heart rates typically reach 75 – 90% of maximum. Energy utilization during the initial phase of HIIT is anaerobic (e.g. muscle phosphagens, muscle glycogen), but these pathways can deplete after about 30 seconds at which point aerobic sources takes over.

LISS training involves prolonged, sustained exercise at a steady pace (e.g. jogging for 60 minutes). LISS training uses slow-twitch, large muscles, and heart rates typically reach 60 – 80% of maximum. Energy utilization during LISS is aerobic. If energy requirements exceed oxygen supply, anaerobic pathways are then utilized.  LISS has faster recovery times than HIIT, and it improves endurance. On the downside, it takes more time and can lead to overuse injuries.

  • This study published in Nature found that HIIT improves insulin sensitivity and helps burn more belly fat when compared to LISS training – HIIT training helps burn more belly fat  
  • Other studies have found that HIIT can increase the effects of  EPOC (excess post-exercise oxygen consumption) which leads to more calories burned after the exercise session is completed – EPOC studies
  • Prolonged LISS training can cause muscle mass to be broken down as an energy source. HIIT prevents this phenomenon.
  • The best part of  HIIT training is that the workouts typically range from 20-30 minutes which makes it easy to incorporate them into a busy schedule.
  • Beginners should ease into HIIT training to avoid injury.  I also do not recommend doing HIIT training more than 3x per week.

In conclusion, HIIT training is an efficient way to get into shape and burn calories. Shoot me an email if you are interested in incorporating HIIT training into your workout regimen.

Happy training,

Kristine