1. They Challenge The Body Differently 

While they often both follow the same time intervals, the impact and intensity of the moves challenge the body differently. HIIT’s aim has always been to get the body working at optimum level. The moves involved work to get you using your energy systems as much as humanly possible, lending itself to everything and anything from indoor and outdoor running to strength training. The main goal is to repeatedly raise and lower your heart rate by giving it all you’ve got in the high-energy periods. As for LIIT a typical programme will incorporate moves that change the level of the body (for example, squats followed by press-ups) which forces the heart to work hard to pump the blood from the legs to the upper body, without having to do a single jump or anything too intense. 

2. The End Results Can Vary 

There’s no doubt that both promise visible results, but recent studies have shown that exercising at a lower intensity puts you in an aerobic state, which experts say burns fat at a higher percentage than anaerobic exercise. To add to that, someone who suffers from chronic stress is only going to add to the increasing cortisol levels with HIIT as it has you working in your Sympathetic Nervous System, which is your ‘fight-or-flight’ zone. With that in mind, LIIT often feels like a safer option with better holistic benefits, but don’t rule it out completely. HIIT still offers seriously toned results within a matter of weeks while releasing toxins and boosting your overall mood. The key is to keep it moderate – for it to be positive and sustainable, it must be balanced out with stretching and strength work and be performed at a maximum of twice a week.   

3. LIIT Is Far Gentler On The Joints

Half the reason LIIT is so popular now is because people are becoming more aware with the longevity of their bodies. HIIT is great for its endorphin-boosting benefits, but there is minimal rest periods. LIIT on the other hand still creates exercise intensity without the impact on the joints. This is because it keeps moves simple – think going from a jog into a walk, rather than a sprint into a jog. Another popular way to get the most out of LIIT it to use a challenging weight and to move slower through the moves, this increases the TUT (Time Under Tension) for your muscles which creates a greater demand on the metabolism while the slower movement allows for more awareness and precision through movement resulting in less injuries. 

4. Both Can Burn A Similar Amount Of Calories

Don’t confuse LIIT’s low-impact nature with being slow and less effective. If you’re using heavy enough weights and really working on those slow, controlled sculpting moves, chances are you’re likely to burn a similar number of calories as a single HIIT session – it just may take you longer than a 10-minute stint. It comes down to preference, schedules and how much energy you like to put into your workouts. 

5. HIIT Is Better For Those Who Are Time-Poor

HIIT was practically designed for those wanting a speedy fast-fix. Typically, a HIIT workout will last you around 10-30 minutes, making it a go-to for those with tight schedules. The best bit is even when performed in a shorter amount of time, it makes no dents in your fitness efforts. In fact, these intense, short workouts are said to burn up to 30% more calories than others. It’s also said to reduce blood pressure and blood sugar, as well as improved oxygen intake, digestion and overall endurance.

6. You Won’t Need Equipment For Either 

Despite their core differences, one key benefit of both is that they can be performed almost anywhere with as much or as little equipment as you desire. Using a mix of strength-training moves, weights and resistance bands, you’ll find you can take on either in your living room or outside. There are some great YouTube workouts you can follow now, too, which is ideal if you still want to reap their toning benefits without joining a group class.  

Here are SL’s Favourite HIIT & LIIT Classes…

1. Low Intensity Class at FLY LDN

2. Pulse at London’s Third Space

3. Various Trainer Plans at FIIT London

4. HIIT at Virgin Active

5. HIIT & Run at KXU