Get access to everything we publish when you sign up for Outside+.
Cardio is perhaps the most polarizing form of exercise on the planet, and typically you’re either a low-key endurance type or a fast and furious metcon type. Regardless of your intensity bent, you could benefit from varying your cardio on the reg. Here are four ways to do your cardio and how each might benefit your goals.
LISS = Low-Intensity Steady-State
Best for: Beginners who need to build an aerobic base or for active recovery for exercisers/endurance athletes of all levels.
Once interval training and HIIT stole the spotlight, this former favorite was benched — which is a shame because it’s probably your most reliable player. LISS is all about aerobic endurance and improved cardiovascular capacity, and working at a steady pace allows the stabilizing muscles, tendons and ligaments in your lower body and core to adapt and build stamina. LISS sessions should last about 30 minutes and should be done at a consistent pace between 65 and 75 percent of your maximum heart rate (MHR) — in other words, you should be slightly out of breath but still able to hold a conversation. As your endurance improves, you can add intervals and higher-intensity workouts to your schedule, but keep LISS around for active recovery days.
Those trying to gain weight and/or muscle should cut back on LISS.
MIIT/MISS = Moderate-Intensity Interval Training/Moderate-Intensity Steady State
Best for: Intermediate athletes looking to level up or advanced endurance athletes looking to increase their mileage.
These two modalities may not make MVP, but they are the best transition players between LISS and HIIT and can transform a power walker into a full-fledged runner. MIIT can break up the bore factor of lengthy cardio sessions by integrating short work intervals between 75 and 85 percent MHR — the point at which it becomes difficult to talk, but you don’t have to slow down or stop. Begin with a work-to-rest ratio of 1:3 — for example, run for a minute and walk for three minutes. Over time, decrease your walking time and increase your running time until you achieve a ratio of 3:1 work-to-rest ratio, at which point you can transition to MISS.
MISS helps you improve the intensity and duration of your race pace, i.e., the fastest pace you can maintain over a target race distance. MISS should be done at 70 to 85 percent MHR, and this intensity should be maintained for the duration of your workout. Start with about 20 minutes and build up to 60, if appropriate for your goals. Once you can maintain MISS for 30 minutes, you can add some HIIT sessions.
If your goal is muscle gain, use MISS with caution: Too much volume can decrease the availability of protein and carbs for muscle-building purposes.
HIIT = High-Intensity Interval Training
Best for: Advanced athletes with limited time or those trying to improve cardio conditioning while maintaining mass and power.
HIIT is undeniably the captain of the cardio team, and tons of research indicates that HIIT burns more calories in less time while preserving muscle and strength gains. Good HIIT activities include things like jumping, sprinting and plyometrics. However, many people think they’re doing HIIT when in fact they’re really doing MIIT: To truly count as HIIT, your heart rate should be between 85 to 95 percent MHR, and you should barely be able to talk at all. Begin with a 1:3 work-to-rest ratio and build up to 3:1, depending on the exercise(s). For instance, do a hard hill climb for one minute on your Peloton followed by an easy three-minute recovery, or run 400 meters hard, then walk 400 meters. Start with one HIIT session per week and work up to two.
SIT = Sprint-Interval Training
Best for: Intermediate and advanced athletes with limited time and those
who can maintain proper form during intense exercise.
This modality is akin to a freshman walk-on but could actually be your secret weapon. SIT requires that you work all-out at max effort followed by several minutes of recovery. Because they are so intense, SIT bursts should last no more than 30 seconds — if you “can” work longer than that, you’re not working hard enough! The intervals can be done with any work-to-rest ratio appropriate to your fitness level and sport, just allow for enough rest in between to ensure your form stays on point. For example, sprint up several flights of stairs as fast as possible, then walk slowly and carefully back down, or do 30 seconds of burpees every two minutes for 10 minutes as a finisher for a lifting workout. SIT workouts that are 20 to 25 minutes in duration should be done no more than twice a week, but when used as a four- to 10-minute finisher, they can be tacked onto the end of your lifting session up to four times per week.
Find Your Level
Here are some suggestions for a month of training for athletes of all levels.
Level 1: Build your aerobic base with three to five LISS sessions per week.
Level 2: Add one to two days of MIIT to your LISS workouts for four weeks, then transition to LISS plus MISS for four weeks.
Level 3: Follow a schedule integrating LISS, MISS and MIIT.
Level 4: Create a program using all four modalities spaced appropriately to ensure proper recovery (see chart).