Clients are always asking me if they should do High Intensity Interval Training (HIIT) or Low Intensity Steady State (LISS) cardio. The reality is you need both.

HIIT vs LISS

HIIT is a form of cardio where you’ll do 20-30 second bouts of all out effort, followed by 30-60 second rest. It repeats 5-6 times and then you cool down. Most sessions are 15-30 minutes long.

LISS is a slower form of cardio where you run at a just above a conversational pace, for 30-40 minutes.  

HIIT Pro’s

• Amazing if you are tight on time
• Burns as many calories in the 15-30 minutes as a 30-60 minute steady state session
• Has the EPOC effect - the 3-4 hours after you train, your body is still burning calories trying to catch up to the high intensity demands you placed on it
• Great for individuals who like to get after it

LISS Pro’s

• Not too taxing on your heart
• Not as high impact on your joints and cortisol as HIIT
• Great for increasing your aerobic capacity
• Maximizes burning fat while keeping muscle at bay

HIIT Con’s

• If done too frequently too often, can keep cortisol chronically elevated leading to problems down the road
• Depending on the exercise, can be hard on your joints
• Increased risk for injury
• More intensity isn’t always better. It could negatively impact your gym performance

LISS Con’s

• Doesn’t burn as many calories as HIIT
• Becomes very boring and mundane after a couple weeks
• Requires longer and longer sessions as the diet continues
• Harder to implement for very busy people 

Hopefully this list is giving you a much better picture of why both have their advantages. You don’t want to be doing too much HIIT, because you might sacrifice muscle during a fat loss phase. At the same time, as your diet progresses, you might need tricks up your sleeve for burning more calories, especially if you are tight on time.

Try This:

For a fat loss phase, similar to lean bulking, I prefer to make sensitization the priority. In other words, instead of just bulking or dieting for 12 weeks straight, I like to intersperse 1 week of maintenance to give your mind a break, and body a break, so that the following week you can maximize the effects.

Weeks 1-3 - Cardio 3 days a week at 30-35 minutes LISS

Week 4 - Maintenance week - Cardio once a week at 30-35 minutes LISS

Weeks 5-7 - Cardio 3 times a week at 30-35 minutes LISS each and 2 times a week at 15 min HIIT intervals

Week 8 - Maintenance week - Cardio twice a week at 30-35 minutes LISS or 15 min HIIT

Weeks 9-11 -  Cardio 3 times a week at 40 minutes LISS each and 2 times a week at 20 min HIIT intervals

Week 12 - Maintenance week - Cardio twice a week at 40 minutes LISS or 20 min HIIT

Let me know how that works out for you! Check out my other articles on dieting, if you’d like guidelines on how many calories to eat while doing this phase. Usually I’d recommend starting with a 20% deficit from your maintenance.