Why Even Do Cardio?

Besides the boost that aerobic exercise, also lovingly known as cardio, gives to your heart, cardio can help you lose weight by burning calories. It can also support and improve your level of fitness, increase your physical endurance, and give your metabolism a boost. The benefits of cardio don’t stop at weight loss, though. It can reduce stress, help you to sleep better, and even give you more energy.

Too much cardio can have negative impacts, like slowing your metabolism and overtraining. So, what kind and how much cardio should you do? If you’re wondering how long and how intense your cardio sessions should be, try comparing the pros and cons of two very popular types of cardio – LISS, and HIIT.

What Is LISS?

Low-intensity Steady State cardio is a prolonged type of aerobic activity that gets your heart rate to about 50-60% of its max. You can determine your max heart rate by subtracting your age from 220. So, if you are 40, your max heart rate is 180. If you are doing LISS cardio, your target heart rate will stay in the 90 – 108 bpm range. You can use any cardio machine in the gym (i.e., elliptical, stair climber, stationary bike, or treadmill), or you can simply go for a brisk walk to engage in LISS cardio. A LISS workout usually spans 30 to 60 minutes or more.

Pros of LISS:

LISS is great for getting your body into the “fat-burning zone,” which several research studies have determined is the optimal heart rate to burn body fat. During a low-intensity workout like LISS, your body is relying on its fat stores for energy, thereby helping you to lose body fat. LISS is also extremely safe and accessible to most people, especially those new to working out, because of the slower pace. There is no recovery time needed after doing this type of cardio, and you are much more likely to make LISS a daily habit. While LISS isn’t a calorie crusher like HIIT, you may be able to do it longer because it’s easier, and you could end up burning more calories in the long run.

Cons of LISS:

The downside to this low-intensity aerobic exercise is that your body can easily adapt, which will lead to a plateau in your endurance and weight loss achievements. You will have to increase the amount of time you do LISS each week to see the same amount of benefits. Also, LISS doesn’t have that “afterburn effect” that many other types of intense cardio seem to give your body, so you aren’t burning more calories after the cardio is over. LISS is also not geared toward improving your athleticism, and it may reduce your metabolism over the long-term.

What is HIIT?

HIIT stands for High-Intensity Interval Training, and the intensity level of this type of cardio is no joke. You will alternate between short bouts of incredibly intense, all-out effort and a less-intense recovery period of cardio. You would, for example, work at your max heart rate for 20 to 60 seconds then slow it down for 1 to 3 minutes. Your total HIIT workout time would only need to be about 20 minutes max, so you are definitely getting more bang for your cardio buck.

To determine if you are really at your peak level of output, you can use a wearable fitness tracker to check your heart rate, or you could use the “speak test.” Basically, if you have a hard time speaking or holding a conversation, you are going all-out. If you can hold a conversation without much effort, then you aren’t working hard enough to get into the peak zone that makes HIIT so beneficial.

Pros of HIIT:

The most significant benefit of HIIT is that you can burn more calories and gain more cardiac and endurance benefits in a shorter amount of time. HIIT is an extremely efficient way to burn calories, and who doesn’t want to spend less time in the gym? Not only will you burn more calories while you are doing your HIIT workout, but you will also benefit from the “afterburn effect” even after your workout is over, which means your metabolism will experience a temporary boost for several hours after your HIIT session. HIIT cardio also improves your overall athletic performance.

Cons of HIIT:

While HIIT sounds like a no-brainer, there are some drawbacks. For one thing, you have to be at a certain level of fitness to engage in this type of intense workout. Beginners might feel intimidated or less interested in starting at this higher level of aerobic exercise. One of the biggest downfalls of HIIT workouts is the risk of injury. When you are engaging in the very intense, all-out portion of the workout, it is hard to maintain proper form, and you will be more susceptible to missteps and injury.

Therefore, you should choose a type of cardio machine or movement that is less injury-prone when first starting out with integrating HIIT into your fitness routine. For example, it’s more advisable to do HIIT on an elliptical machine, where your feet are firmly planted on a footbed instead of doing HIIT on a stair climber, where a misstep could be disastrous.

So, Which One Should I Do?

Well, you really need a balance of both LISS and HIIT to receive the benefits that each type of cardio workout has to offer. Ideally, you should do a HIIT workout one to two times per week for no more than 20 minutes at a time. In addition, you can do a LISS cardio session every day, since there is no recovery time needed. So, going for a daily 30- or 60-minute walk is a great way to get the benefits of LISS cardio.

To make sure you are in the fat-burning zone, regarding your heart rate, a fitness tracker could help you track this. Ultimately, your workout and your body need a variety of exercise types to prevent adaptation and a weight loss or strength gain plateau.