Low Intensity Steady State (LISS)

LISS is likely what you think of when you think of old school cardio. It is often done when walking, jogging, and cycling. A lot of manual labor and tactical operations occurs in this area- shoveling dirt, spreading concrete and rucking/patrolling.

Now to the science side:
For now, we will consider LISS the same as Zone 2 cardio. There are many different cardio “zones”. We will define Zone 2 as the highest aerobic output without tapping too much into the anaerobic system for back up. This can be determined with a HR Monitor (~80% HRmax). More easily, it can be determined as the intensity at which holding a conversation is possible, but very difficult. The most accurate way to determine it is through blood lactate (<2-4mmol). The blood lactate level is not something that you will need to pinpoint.

Zone 2 Cardio (LISS) primarily targets type 1 muscle fibers which have a great deal of endurance and are very aerobically capable due to many factors such as the mitochondrial density. This is a true “fat burning” type of cardio - we will discuss the implications of this at a later time. Almost all (not 100%) of the energy required for these activities is derived from fat. Thus, aerobic systems are primarily responsible for metabolism in this state. Some of the primary goals for training at this intensity are to improve cardiorespiratory fitness and mitochondria size, quantity, and efficiency.

Practical Application:
Exercise at this intensity should be sustained for at least 30 mins (research is showing more like 45) at a time to cause any real adaptations. This is a low stress form of exercise, thus; it should be performed 3-7 times per week.
Note: This is NOT an EASY pace, if you do not reach very close to the threshold of becoming more anaerobic then the adaptations will be minimal (there is still being fat burned if you do not approach the threshold).