Cardio: LISS vs. HIIT

Some love it, some hate it, and many of have a love-hate relationship with cardiovascular training. In recent years, fitness experts are recommending cardio less than ever, with focus shifting to resistance training. However, although informed exercisers may no longer be doing hours on the treadmill, it’s still important to take care of our heart! Incorporating cardio into a balanced exercise plan can be effective for weight management, mood and general good health.

But what’s the best way to get your cardio in? The answer isn’t so simple! There are two main types of cardio you can incorporate into your exercise routine: “HIIT” and “LISS”. Let’s take a look at these in depth…

Low Intensity Steady State (LISS)

What is LISS?

  • Generally lasts 35-60 minutes

  • Heart rate stays steady at around 60-70% of your maximum heart rate

  • To approximate your ideal heartrate for LISS, subtract your age form 220 (e.g. 40 years of age: HR = 220-40 => 180 beats per minute)

  • Aerobic exercise

What are the benefits of LISS?

  • Touted as the “fat-burning zone” since at this intensity, the body utilizes a higher percentage of fat as fuel

  • Can be used as "active recovery" in a resistance training program

What are the downfalls of LISS?

  • May take up to an hour

  • Does not burn calories as efficiently as HIIT

When to use LISS?

  • Easy to incorporate on days you are strength training or on active rest days

  • LISS may be beneficial in recovery from heavy weightlifting since it pumps blood through the muscles but remains at a low intensity with minimal muscle damage

High Intensity Interval Training (HIIT)

What is HIIT?

  • True HIIT generally lasts 15-20 minutes

  • Alternates between work periods (at 70-90% of maximum heart rate) and rest periods (at 60 to 65% of maximum heart rate)

  • Uses anaerobic energy systems (creatine-phosphate system and anaerobic glycolysis)

What are the benefits of HIIT?

  • Torches calories at much faster rate than LISS

  • Results in EPOC (excess post-exercise oxygen consumption), with up to 15% of calorie burn taking place in the hours after you are done exercising

What are the downfalls of HIIT?

  • Very strenuous on the nervous system

  • Requires about 48 hours of recovery between sessions

When to use HIIT?

  • Excellent when you are crunched for time

  • Best not to do on days you are strength training since both are taxing on the nervous system