Niagara Gazette — Have you heard fellow gym members using words like “hit” or “liss” when discussing cardio training?
These are important words in my gym.
“Hit” is actuallly HIIT, which stands for High Intensity Interval Training, which consists of short sprints coupled with low to moderate intensity work.
We have our clients sprint on an elliptical for 15 seconds and then go at a normal pace for the next 45 seconds to bring the heart rate back to normal, then repeat for a pre-determined number of times.
LISS stands for Low Intensity Steady State Cardio, which consists of purely low- to moderate-intensity work. An example of this would be walking on the treadmill or riding the bike and being able to hold a conversation (we tend to see a lot of this at corporate gyms).
Let’s look a little further at the science and benefits of each.
This is a simple test: If you can carry on a conversation, you are performing LISS.
When doing HIIT you push for greater improvement in metabolism which leads to better fat loss over time. You would do HIIT for less duration of about 20-30 minutes of total work versus 45-60 minutes of typical cardio. When you can save time and have better results you have a winning workout.
How does HITT improve your metabolism?
• Adding muscle tissue — In the progressive overload theory, your body adapts to the stress you place on it, so you must continually find ways to increase the demands you place on your body, such as shorter rest periods between sets, increasing weights used, increasing volume (doing three sets instead of two) or adding in another weight training day.
• Increase your muscle’s oxidative capacity — Your muscles have these energy-producing units called “mitochondria” and this is where fats are burned. The more mitochondria you have and the more active they are, the greater oxidative capacity you will have for fat loss. HIIT increases mitochondrial capacity and you actually increase the amount of mitochondria you produce. Studies show that you get greater fat loss through high intensity training because of the increase in oxidative capacity.
With LISS you’re only burning calories at that precise moment, there’s no 16- to 24-hour energy expenditure and boost in metabolism.
This isn’t the most efficient way to do things. Your body will adapt to LISS and you will have to continually increase the duration for the same benefits. With HIIT you are burning calories during the torture session, but also for the next 16-24 hours.
A study conducted at the University of Tampa shows when you add LISS to your workout you get a temporary boost in weight loss. Subjects lost a couple of pounds the first week, than weight loss stalled. This happened because their metabolism completely adjusted to the LISS and that became their new set point to what they had to do just to maintain their current weight.
So, would they do more cardio and eat less to get results? Sounds reasonable but, unfortunately they would likely end up in a worse position. LISS with a low-calorie diet is terrible for fat loss and could cause muscle loss.
If you get too aggressive in your fat-loss goals — too much cardio, restricting calories — you have a strong possibility of losing muscle tissue. At some point, you will likely begin to consume more calories and reduce the amount of cardio you are doing. Once this happens, your body will gain weight. Unfortunately, you’ll gain body fat back and will not gain the muscle tissue that you lost. Essentially, you will weigh more and have a higher body fat percentage which equals a “muffin top” and a slower metabolism.
So why does HIIT work so much better than LISS?
HIIT has been proven muscle retention because when you’re doing LISS — like walking — you’re not activating muscles the same way as if you were lifting weights. When you sprint you have hip flexion, knee extension, and those are movements performed during weight training — like leg workouts. HITT is just another way, like weight training, to overload the muscle.
I believe in doing both HIIT and LISS.
• You can’t do HIIT five to six days a week because eventually it will have a negative impact on your weight training, thus interfering with lean muscle growth, which is not good.
• Many people have legitimate orthopedic, and/or cardiac reasons to avoid HIIT, so LISS is their only option.
• New gym goers may not have the cardiac endurance, coordination, confidence or a strong enough baseline fitness level to begin with HIIT.
• HIIT could be dangerous if not used correctly and could lead to injury.
• When working around any injury, LISS may be the only form of exercise/cardio you are able to do in a pain-free fashion.
I’m a firm believer that both HIIT and LISS cardio each have unique benefits. I feel they both should be incorporated into your routines.
Chris Tybor is a personal trainer and owner of Christfit, which has locations in Lewiston and Niagara Falls. For more information visit www.chrisfit.net.