Long Slow Distance Running Versus HIIT

Get out your sports drinks and pull up a spot on the treadmill for what’s become a marathon debate. The question of which form of training is better – long, slow, distance running (LSD), or High Intensity Interval Training (HIIT) – really all comes down to your goals. As with most things, the “How” is more important than the “What,” and the good news is, treadmills and other cardio machines on the market today all come loaded with options to fit either style of workout, or both. To be well-rounded, one needs to incorporate both strategies into their workout plan while favoring the one which suits them best.

A quick Internet search on the topic will lead one to believe that HIIT outperforms LSD on all measures and that’s simply not true. There are advantages and disadvantages to both for sure.  You’ll never win marathons using HIIT alone after all. Over the years I’ve transitioned back and forth depending on my sport and found that individual preferences rule the day. But as with all things, knowledge is power and definitions are the key. But if you’ve ever wondered why marathon running and sprinting produce different body types, here’s your answer: LSD versus HIIT.

The NordicTrack Commercial 1750 is a great unit for either HIIT or longer runs. Photo by: Oleksandr Kosheliev / TreadmilReviews.net

What’s the Difference Between LSD and HIIT?

High Intensity Interval Training is an umbrella term which you’ll see linked to a number of different workout programs ranging from cardio to strength and even stretching. Traditionally HIIT is an on-off-on style of workout where you’ll maximize your exercise intensity for 20 to 45 seconds and then reduce intensity for as long as 60 to 75. During this period of lower intensity you’ll still be moving though. For example, on a treadmill you may sprint for 20 seconds, jog for 20 seconds, then walk for 20 seconds, before sprinting again. With HIIT training you’ll want to avoid exceeding 75 seconds of intense bursts which is the point at which a different set of muscle fibers kick into gear and you begin activating your actual cardiovascular system. Sprint interval training is a form of HIIT commonly found on treadmills where you’ll seek to achieve a maximum effort in terms of heart rate at your peak, and then slow down the movement letting the heart rate fall with it, before sprinting again. If you’ve been shopping for treadmills lately you’ve probably encountered the term heart rate training and heart rate zones, which all fall under the HIIT umbrella. The Horizon 7.8 AT is one of many which caters to this style of exercise.

Likewise, Long Slow Distance training is a catch-all term for continuous training where you’re maintaining a slower pace for a longer period of time over distance. Perhaps you’ve seen the terms Low Intensity Steady State (LISS) and Steady State Training (SST) in your reading. The whole point here is to avoid the ups and downs or sprinting as you work toward a goal, perhaps the completion of a 5-kilometer race. As with HIIT, LSD programs will vary by the individual, but as a rule, any distance past the peak of your sprint would mark the transition into LSD. This type of training can include anything from quarter-milers to the 26.2-mile marathon and beyond. The Sole TT8 comes with a number of features, from its self-lubricating deck to its three-inch rollers which make it ideal for longer runs.

With LSD your goal is typically to keep the heart rate around 50-65% of maximum, while with HIIT you’re aiming for bouts of 80-95% in between periods of 40-50%. All good treadmill fans know you can’t sprint continuously for 10 miles, or even 10 minutes. Just as there’s a limit to the number sets a powerlifter can perform on the bench press, there’s a point of diminishing returns with HIIT. You can definitely exercise for longer periods of time using LSD. So if your goal is fat loss, which burns more calories, higher intensity for shorter periods, or lower intensity for longer periods? Probably lower intensity for longer periods as we’ll explain below. If you’re looking to build strength but want to maintain flexibility and endurance, which should you use? Probably HIIT. The best solution is to use a little bit of both.

The next point to consider is that of muscle fibers. The human body has different types.

• Type I: Slow-twitch
• Type IIa: Fast-twitch oxidative
• Type IIb: Fast-twitch glycolytic

Type I muscle fibers primarily burn oxygen and are associated with long-distance running, jogging, walking, and activities involving the cardiovascular system. Type II of both kinds provide shorter bursts of power and are associated with weightlifting, sprinting, and jumping. The difference between the Type IIa and IIb is in whether they burn oxygen or glucose. The Type IIb use a glycolytic process to burn sugars during a short burst of “fight-or-flight” style activities, while the Type IIa uses oxygen. When performing LSD you’ll be working your Type I fibers, whereas with HIIT you’ll more directly tap into both of the Type II fibers. And of course, this answers the question of why Olympic sprinters look more like bodybuilders than marathon runners. They’re recruiting the same muscle fibers.

Like weightlifting, HIIT training can break down muscle fibers due to the intensity. If incorporating HIIT training into your workout, you might only do two of those sessions per week compared to three or four LSD-style runs. If you’re a weightlifter looking to increase power and stamina, then one or two HIIT cardio sessions mixed into your weekly workout would be the plan, whereas a serious distance runner might choose to only spend one day a week with sprints.

Pros and Cons of HIIT

We’ll start with HIIT first because frankly it’s all the rage in the world of treadmill training. The single biggest advantage to HIIT training for cardio is the time spent. In this busy day and age, the idea of getting in a quick 15- to 30-minute workout is much more appealing than jogging for an hour. The authors of a recent study published in the Journal of Endocrinology, Metabolism and Diabetes of South Africa write that “the findings of this review suggest high-intensity interval training to be the most effective form of exercise.” The article, which describes a systematic review of randomized controlled and crossover trials, analyzed the two different exercise styles as interventions to improve glucose control and insulin sensitivity in type 2 diabetes patients. Aerobic exercise was associated with improved glucose control relative to resistance exercise. Continuous aerobic exercise, or LSD, significantly lowered average glucose during the first 24 hours post-exercise, but interval walking decreased both mean and maximal blood glucose. When considering the amount of time spent on the workouts involved, it’s clear that you get more bang for your buck with HIIT.

The HIIT workouts also help develop core muscles and strength, whether sprinting or hard hiking. Most treadmills these days feature incline/decline options and if you’re looking for a way to build up your quads and hamstrings, HIIT hiking programs are the way to go. Because HIIT alternates your heart rate from high to low it does tend to produce a lower overall resting heart rate and higher metabolism. If you’re looking to increase your speed, power, and lean muscle mass, HIIT is the way to go.

The downsides to HIIT include recovery time and potential for injury. Your body simply isn’t meant to sprint in perpetuity. It’s also tough to maintain the motivation to give it your all while training alone. My experience has been that HIIT is also very tough for older folks and newbies to actually perform. You have to be at a certain level of conditioning to reach that 80-95% heart rate zone, and if you’re just starting out, you might wind up going through the motions. Keep in mind that all of the studies which indicate HIIT works keep a watchful eye on the participants heart rate and other metrics. As with any exercise program, be sure to consult with a medical professional if you’re concerned that injuries or excessive fatigue could become a problem. If you’re looking to make a drastic cut in overall weight and are starting from a point where mobility is a problem, then signing up for a 5K walk/run and using LSD might be a better route.

Pros

• More time-efficient
• Builds strength
• Partners well with a barbell workout
• Spikes metabolism

Cons

• Potential injury and over-exertion
• Difficult for beginners

Pros and Cons of LSD

There’s a reason running and jogging for distance remain so popular. The fact is they work. The LSD workouts train your body to burn fat as a fuel as opposed to glycogen. Your body’s fat is stored energy which gets burned during longer bouts of exercise. Meanwhile, the HIIT seeks to use the body’s sugars. Longer runs require more time and therefore typically burn more calories per session. In theory you can burn as many calories during a 15-minute HIIT session as a 45-minute run, but in practice it’s difficult to do. There’s also a big difference in the type of stamina and endurance created by LSD and HIIT. Sprinters don’t run marathons but marathon runners can sprint. If you’re worried about LSD reducing lean muscle tissue, don’t. Studies continue to show that unless taken to extremes, as is the case with ultra-marathons, that simply won’t happen. One study published in the International Journal of Sports Medicine demonstrated long-distance running is associated with minor, if any, skeletal muscle changes.

Longer jogs are also enjoyable. For many, the 45 minutes spent jogging on a treadmill to music is a relaxing distraction. The same is true of walking. These activities are easy to do for most people irrespective of fitness level and can be done with minimal damage to the body. The LSD-style of training also brings a number of fun goal-oriented, like preparing for a 5K or marathon. These activities can be done indoors and outside with other people. If you’re serious about losing a large number of pounds, you’re more likely to fall in love with jogging and whittle one to two pounds down per week over a year while training for group-style competitions like races.

The biggest downside to LSD is the time required and it’s not as effective at building muscle while burning fat.

Pros

• Burns more calories per session
• Good for sport-specific training
• Easier on joints

Cons

• Takes more time
• Doesn’t provide the same strength-building
• Harder to schedule LSD while engaging barbell workouts

The Verdict

I hate to say it all depends, but it really does. The reason every fitness app I’ve reviewed to date has both styles of workouts programmed in is that both work depending on your goal. Irrespective of that though, everyone can benefit by mixing a little of both into their routines. If you’re looking to increase strength and lean muscle tissue while losing weight, HIIT is great and it only takes a few minutes a day. If you need the motivation to lose big chunks of weight over time by way of marathon training, then LSD would be the way to go. HIIT works better for those who want to incorporate cardio workouts into barbell training, while distance running is a sport in and of itself.

If you’re shopping for a treadmill right now check out our Five Step Treadmill Buying Guide as a reference. And if you do want a treadmill that addresses a specific goal, like HIIT training as opposed to marathons, then be sure to check the specs of the machine before buying. Long distance running and LSD requires a longer deck, say 60″ x 22″, whereas you can perform HIIT using hiking workouts on a much shorter unit so long as it offers the incline/decline function. It also helps to perform HIIT training with training apps and Bluetooth heart rate monitors. The iFit workout is one of many that specializes in HIIT workouts with both live and on-demand programs, as well as automatic trainer control built into the treadmill. Automatic trainer control allows the machine to take over the workout and adjust the resistance in accordance with the program and leave you to the huffing and puffing. Meanwhile, if you’re content to run at a set pace for a certain number of minutes or miles, you might be happier simply playing music.