- What is Low Intensity Cardio?
- High Intensity Interval Training vs. Low Intensity Cardio
- How Fat Loss Really Works
- 8 Benefits of Low Intensity Cardio
- Everything You Need to Know to Do Low Intensity Cardio
- 3 Sample Low Intensity Cardio Plans
- Who Should Use Low Intensity Cardio?
- The Bottom Line: You Need Low Intensity Cardio
Just like dietary guidelines, fitness fads come and go. Right now, low intensity cardio is unfashionable, while high intensity interval training (HIIT) is all the rage in the fitness world.
But contrary to popular belief, low intensity cardio has unique benefits for fat loss, fitness, and overall health.
And as with nutritional advice, the full truth about exercise doesn’t always fit into headlines.
In this article, you’ll learn the pros and cons of low intensity cardio and HIIT , 8 benefits of low intensity cardio, and how to add it to your fitness routine with easy-to-use examples.
You’ve probably already heard of low intensity cardio (LIC for short). It’s sometimes called slow cardio, endurance exercise, or just plain aerobic training.
Think of low intensity cardio as “conversational cardio.” Translation: you can speak in full sentences comfortably as you do it!
This type of exercise uses a sub-maximal level of exertion to improve endurance, enhance fat-burning, and increase the efficiency of your heart, lungs, and cardiovascular system.
Any sustained activity between 45% and 65% of your VO2max (maximal oxygen consumption) works for low intensity cardio[*].
Therefore normal walking, for example, isn’t LIC.
While walking you’ll still burn some fat, but it’s not intense enough to increase your aerobic fitness or lead to adaptations over time unless you have been sedentary for years[*].
And low intensity cardio doesn’t have to be low intensity steady state (LISS) cardio, either. You can use easy intervals, and circuits work great, too.
Low Intensity Cardio and Fat Burning
Appropriately done, low intensity cardio burns more fat than any other type of activity–both as a percentage of calories, and in grams of fat per minute[*].
Because of the lower intensity, 50-80% of the calories you burn during LIC are from fat[*]. Put differently, under the right circumstances, you can burn up to 1.3 grams of fat per minute (or an astounding 1.5 grams if you follow the keto diet)[*].
These fat calories can come from a meal, stored body fat, or lipids stored in the form of intramuscular triacylglycerols (IMTGs)[*].
On the other hand, when an activity gets too intense, your body reaches its anaerobic threshold. Any activity 65% of your VO2max can switch your body’s primary fuel source away from fat[*].
With more intense cardio, you not only burn less fat as a percentage of calories expended–absolute fat burning (measured in grams per minute) also decreases[*].
And according to a study of over 300 men and premenopausal women, women burn significantly more fat than men during LIC performed at 41-61% of VO2max[*].
However, your training history, age, diet, and other factors also influence your ability to burn fat at different intensities[*].
And regardless of who you are, the longer you do low intensity cardio, the higher your fat-burning threshold becomes[*].
So if low intensity cardio is so great, why is high intensity interval training (HIIT) arguably more popular right now?
The truth is, they’re different. Each has various benefits, drawbacks, and applications.
A popularity contest is no way to determine the best training methods.
In the end, you’ve got to experiment and see what works for your goals at a given time. And some people may find they prefer one over the other or respond better.
But to help you make a wise decision, here’s what the data says about how they compare.
Is HIIT More Time-Efficient Than Low Intensity Cardio?
One of the most common talking points in favor of HIIT is that it’s supposedly much more time-efficient than low intensity cardio.
That’s not necessarily true, however. A 2019 PLoS One meta-analysis found that on average, HIIT saved overweight and obese adults 9.7 minutes per session[*]. Saving nearly ten minutes is okay, but it’s not revolutionary!
A separate 2017 meta-analysis of 31 studies found HIIT wasn’t necessarily more time-efficient for calories burned, and that longer low intensity cardio may be more effective than shorter HIIT sessions[*].
And in a 2016 study, 30 minutes of steady state low intensity cardio burned more calories and caused more “afterburn” than shorter bouts of sprint intervals or high intensity intervals[*]
Fat oxidation during exercise may increase with extended activity after 20 minutes, another reason “time-efficient” isn’t the same thing as “optimal for fat loss”[*].
What about fitness? HIIT works great for improving fitness, until it stops working. You can plateau pretty quickly–just three weeks in the famous Tabata study[*].
On the other hand, low intensity cardio can keep you getting more fit for months or years.
And it turns out the fat loss results from HIIT and LIC studies follow the same pattern as fitness, with early fat loss plateaus occurring in HIIT but not low intensity cardio.
A meta-analysis of 36 separate studies found that when trials of HIIT lasted for longer than 12 weeks, they were less likely to show significant fat loss benefits[*].
Translation of the previous paragraph: for sustained fat burning over a period of weeks, low intensity cardio is a better choice than HIIT.
Low intensity cardio is also more effective overall for burning fat, especially if you have the time for longer sessions.
In summary, then, it’s debatable whether HIIT is truly more time-efficient after all, but even if it is, it’s still not the top pick for maximal or long-term fat burning.
What About EPOC?
The fitness headlines will have you believing that EPOC from HIIT is a revolutionary way to lose unwanted fat by burning extra calories, but is this idea accurate?
Excess post-exercise oxygen consumption, EPOC for short, is a technical way to describe energy your body spends going back to a state of balance after a workout. Some people call it “afterburn.”
But did you know HIIT isn’t the only way to increase EPOC?
Resistance training boosts EPOC even more than HIIT, while low intensity cardio also elevates it[*].
Low intensity cardio can raise EPOC by 7% of calories burnt during the session, while HIIT may raise it by up to 14%[*].
Other studies have found no EPOC difference between the two modes of training, but let’s give HIIT the benefit of the doubt for a moment and examine the best-case scenario for added calorie burn after the workout[*]:
- If you burn 600 calories during a low intensity cardio session, you’ll burn an extra 42 calories after the session[*].
- A 600 calorie HIIT session means a “whopping” (not really) extra 82 calories burnt after the session[*].
Going by the numbers above, EPOC from calorie-matched HIIT (versus low intensity cardio) might result in one additional pound of fat loss every six months if you did three sessions per week.
And keep in mind that low intensity cardio is not only an easier way to burn calories, it’s also a far more efficient way to burn fat calories as opposed to other fuel sources[*].
To sum up, evidence for a meaningful EPOC effect of HIIT is mixed, but what’s indisputable is that calories burnt during the session make a more significant difference in fat loss than EPOC.
That’s yet more evidence in favor of low intensity cardio.
Does Low Intensity Cardio Make You Slow and Weak?
As a matter of fact, a large 2018 meta-analysis from the Journal of Sports Science found that HIIT, not LIC, may decrease lower body strength, as well as slow your strength and muscle gains from weight training[*].
The hypothesis of how HIIT works for fat-burning is by increasing EPOC. Do you think that taxes your body’s recovery capacity? Absolutely it does[*]!
Bottom line: if you’re slow and weak, train to solve your fitness shortcomings. Don’t blame a lack of fitness on low intensity cardio.
And if you are already fast and strong, low intensity cardio won’t make you slow and weak.
HIIT: Low Enjoyment and Increased Appetite
After all, if you don’t enjoy an activity, chances are you won’t do it long enough to benefit. (Another study found a low participation rate for “unsupervised” HIIT)[*].
HIIT’s ability to increase hunger and food intake may be especially pronounced for overweight people[*].
We already know that not overeating is more critical than doing lots of cardio to create a calorie deficit.
Remember that a single binge can set you back a week’s worth of calories from cardio, so don’t overlook the impact of increased hunger.
Should I Do HIIT or Low Intensity Cardio?
In the end, you need to experiment with both methods if you want to learn which one really works best for you.
However, HIIT probably isn’t the game-changer that fitness headlines make it out to be. And low intensity cardio is definitely underrated.
There are plenty of studies showing comparable results for fat loss and health, and low intensity cardio is undoubtedly easier[*].
Why make things harder than they need to be?
Consider low intensity cardio over HIIT if you:
- Are a beginner to healthy weight management and fitness, or if you’re sedentary
- Want to burn as many fat calories as possible
- Don’t want to overtax yourself or overtrain
- Are currently lifting weights to gain strength or muscle mass
On the other hand, HIIT isn’t without its upsides. More intense exercise like HIIT may release more “feel-good” endorphins, for one thing[*].
And if you aren’t keto, HIIT might work slightly better than low intensity cardio after meals that include carbs.
For maximal fat loss, you can even combine the two cardio approaches. But because you’ll plateau much earlier on HIIT, you might be wise to save it for a time when you want to step on the gas to get faster results.
One last thing: don’t even think about prioritizing your exercise routine over your diet. Plenty of exercise studies that allow participants to eat whatever they want find no benefit for body composition with HIIT or low intensity cardio[*][*].
We’ve already seen how HIIT isn’t always superior to low intensity cardio when it comes to calorie burn.
But calorie burn isn’t the only variable that counts for fat loss, in any case. Calories in, calories out doesn’t paint a full picture when it comes to fat loss.
How could it? Fat loss is complex, involving metabolic, hormonal, neurological, and homeostatic systems. A simple equation like A-B=C could never describe such an intricate process with total accuracy.
A calorie deficit does not necessarily ensure you are losing fat, either. Keep reading to learn why this is an essential fact for understanding the benefits of low intensity cardio.
OK, So What Does It Take to Lose Fat?
To eliminate adipose tissue (fat stored in your body), you need the following and not much more:
- Lipolysis (the release of stored fats into your bloodstream)[*]
- Transport of fats across cellular and mitochondrial membranes[*]
- Elevated oxidative metabolism in muscles (fat-burning and increased demand for fat as fuel)[*]
Remove any of the three factors above from the equation, and you’ll burn drastically less stored fat (or even gain fat).
But maximize all three, and you can burn ridiculous amounts of stored body fat.
And the best ways to do this have almost nothing to do with counting calories per se.
Low intensity cardio can also increase your calorie burn and boost fat oxidation at the same time. In other words, you are burning more calories, and not just any calories–the very calories you need to burn to shed unwanted fat.
In contrast, HIIT reduces lipolysis and temporarily shifts your metabolism towards using carbs for energy[*][*][*]. (Eating carbs before exercise does the same thing[*].) Reread this paragraph a couple of times and ask yourself if that’s optimal for fat loss.
Essentially, low intensity cardio enhances all three elements you need in place to lose fat. It’s not all you need to lose fat, but it can make the entire process work a lot better.
In the next section, you’ll learn more about the benefits of adding low intensity cardio to your regular regimen.
#1: Endless Fat Loss
Whereas carbs can only fuel skeletal muscle contractions for about 90 minutes of exercise, fat could fuel 120 hours (five days!) or more of continuous physical activity[*].
And theoretically, your body could sustain its maximum fat oxidation rate for 8 straight hours or longer during low intensity cardio[*].
Considering that if you’re on the ketogenic diet you may be able to burn over 1.5 grams of fat per minute, that’s an astonishing amount of fat-burning[*].
That’s not to say you should regularly perform eight-hour cardio sessions. Far from it! But at the same time, high-volume low intensity cardio is undeniably the best hack to lose fat really, really fast.
Therefore, if you want to lose as much fat as possible, doing plenty of low intensity cardio each week can offer you the most significant boost compared to other methods, assuming you have an appropriate diet in place.
And if you do your low intensity cardio fasted before breakfast, it can boost your fat oxidation for a full 24 hours, with no need for marathon sessions or extended fasts[*].
Because of its potent effects on fat-burning, studies show that compared to a calorie deficit induced through diet alone, low intensity cardio can result in greater reductions in visceral adipose tissue (VAT), also called visceral fat[*].
That’s one of many reasons low intensity cardio is good news for your health, even if you aren’t overweight. Visceral fat is associated with a 275% relative risk of cardiovascular disease and 208% relative risk of death, and up to 40% of people of normal body weight have it[*].
Lastly, keep in mind that unlike HIIT, you can grind away at LIC for months without plateauing or experiencing diminished fat loss results[*].
#2: Easier Fat-Burning (Permanently)
The longer you stay on a low intensity cardio program, the easier it gets to burn fat[*].
Let the implications of that sink in a moment.
This is particularly important if you think you have a slow metabolism or have trouble losing fat:
Overweight and obese people aren’t as good at burning fat as leaner people, on average. But along with going keto, low intensity cardio can help you change that[*].
Both of these practices (going keto and doing low intensity cardio) can increase the expression of an enzyme called carnitine palmitoyl-transferase 1, or CPT-1 for short.
Obese and diabetic people may have less CPT-1 than healthy people, which is a bad thing, because this enzyme is necessary to transport fats to mitochondria for fat-burning[*].
For example, a study from the journal Diabetes found that in people with type 2 diabetes, a 3-month low intensity cardio program increased their fat metabolism by 29% by boosting CPT-1 levels[*].
Results are similar in people without diabetes[*].
And while the effects are cumulative over time, even a single low intensity cardio session boosts your CPT-1 levels, making your body better at fat-burning[*]. How’s that for motivation to train?
#3: Fantastic for Brain Health
Low intensity cardio appears to reduce inflammation in your brain, possess antidepressant-like effects, boost neurotransmitters, and increase brain plasticity (making it easier to learn new things)[*][*][*][*].
It may even help reverse depression and lower the risk of certain mental health problems[*].
Researchers think neopterin, a compound released by the brain during aerobic exercise, could be behind the reductions in oxidative stress as well as partially responsible for reduced depression after exercising[*].
Other research shows that low intensity cardio may be able to diminish depression yet another way: by changing the state of your nervous system[*].
And you’re probably familiar with the feel-good chemicals endorphins, but what about endocannabinoids?
These brain signaling chemicals resemble those found in the cannabis plant and may help regulate brain areas responsible for emotional function and processing, like your amygdala, hippocampus, and hypothalamus[*].
Endocannabinoids may also be primarily responsible for “runner’s high”[*].
A single endurance training session at 70-80% of max heart rate releases endocannabinoids more effectively than other exercise intensities between 50-90%, according to a 2013 study[*]. This effect may translate to major mood-boosting from low intensity cardio.
A 2019 mouse study comparing various intensities and modes of exercise found that moderate intensity continuous training (“MICT”), a technical name for low intensity cardio, also improves cognition by regulating oxidative stress in the brain[*].
#4: More Relaxation and Faster Recovery
The restorative and relaxing properties of low intensity cardio are healthy for your entire body, not just your brain.
Heart rate variability (HRV) scores, a way to measure autonomic nervous system states, are higher when you are relaxed and rested and lower when you’re stressed or sleep-deprived.
A high HRV typically correlates to a parasympathetic state, sometimes summarized as “rest and digest, feed and breed.” As you can imagine, sleep, food intake, digestion, and production of sex hormones are good for you and good for your recovery from physical activity.
Bottom line: low intensity cardio raises HRV, which helps you recover, enhances your heart health, and helps you live a long and healthy life.
Other effects of low intensity cardio come from vagus nerve stimulation. When LIC stimulates your vagus nerve, which extends from your skull to your abdomen, it increases parasympathetic activity (while also sending an anti-inflammatory signal to your entire body)[*][*].
Another way low intensity cardio can speed your recovery is by lowering your cortisol levels. If you do regular LIC, your body will convert more cortisol to its inactive form, cortisone[*].
#5: Decreased Inflammation
We’ve already touched on the fact that low intensity cardio can reduce inflammation in your body.
As discussed, it can activate your vagus nerve as well as decrease IL-6, both of which help reverse inflammatory processes in your body[*]. But those aren’t the only ways LIC decreases inflammation.
A 2019 review of the effects of aerobic exercise in healthy middle-aged and older adults found it reduces C-reactive protein, tumor necrosis factor-alpha, and IL-6[*]. The researchers speculated that reversing low-grade inflammation with low intensity cardio may reduce adverse effects people experience during aging.
And a 2018 study of the effects of resistance training and low intensity cardio in healthy men found similar results, too[*]. The researchers concluded that the beneficial changes in inflammation markers were likely due to decreased visceral fat (belly fat) in this case.
Now, if you know anything about insulin resistance, you know it’s associated with higher inflammation, too, just like visceral fat.
In type 2 diabetic patients and people without diabetes alike, low intensity cardio can be equally effective at reducing blood glucose compared to HIIT, and some studies suggest it’s also equally good at improving other markers of insulin sensitivity[*][*].
Low intensity cardio may also improve intestinal glucose uptake, which relates to insulin sensitivity, better than HIIT[*].
In summary, low intensity cardio decreases inflammation through vagus nerve activation, reduction of inflammatory cytokines, lowering C-reactive protein (CRP), reducing belly fat, and enhancing insulin sensitivity.
#6: Better Cardiovascular Health
Have you noticed yet how low intensity cardio offers many related, and even overlapping, health benefits?
Cardiovascular health improvements, one of the most potent benefits of low intensity cardio, also follow this trend. There’s no doubt that aerobic training is excellent for your heart and circulatory system for a myriad of reasons.
Some of the cardiovascular health benefits of LIC come from HRV changes. Here’s a quote from a peer-reviewed journal that makes this point:
“These changes reflect an increase in autonomic efferent activity and a shift in favor of enhanced vagal modulation of the cardiac rhythm. Regular aerobic training of moderate volume and intensity over a minimum period of 3 months seems to be necessary to ensure these effects, which might be associated with a prognostic benefit regarding overall mortality.”[*]
In other words, low intensity cardio may help you live longer by making your heart healthier–but you have to do it regularly and for long enough. Not only that, other forms of exercise don’t appear to have this particular benefit.
But low intensity cardio also makes your heart and circulatory system healthier by reducing oxidative stress, which is cellular damage from a faulty metabolism and other environmental factors.
Basically, LIC can decrease damage that occurs to your cells, while other more intensive forms of exercise may increase oxidative stress, particularly if you’ve already got heart disease or other health problems[*].
#7: Improved Aerobic Fitness
Most of the benefits we’ve already explored relate directly to improved aerobic fitness. The fitter you get doing low intensity cardio, the better you get at burning fat, for example[*].
Along with its positive health impacts, aerobic fitness is a benefit unto itself. At least, it’s incredibly handy for athletes and other people who value their overall fitness.
But do you still need aerobic fitness if you aren’t a triathlete or marathoner?
Yes. Most athletes and fitness enthusiasts can benefit tremendously from low intensity cardio.
The HIIT craze brought with it misconceptions that aerobic training makes you slow and weak, but as we’ve already covered, that’s untrue.
The truth is unless you’re a pure strength or power athlete (like a powerlifter, Olympic weightlifter, or thrower), low intensity cardio can help you “gas out” less often and maintain performance longer.
Here’s how it works.
When you exert yourself hard for more than a couple of seconds, your heart rate goes up. And if it goes up high enough, you can bet you’re no longer in the aerobic or fat-burning zone, because you’re working too hard.
You can only sustain anaerobic efforts for 10 seconds (maximum effort) or 2-3 minutes (in the case of intermediate intensity that relies on your glycolytic-lactate energy system).
But the better your aerobic fitness gets, the bigger your “easy” aerobic zone is, the higher your lactate threshold, and the faster your heart rate recovers to baseline or the aerobic zone between anaerobic efforts[*].
Stroke Volume Increases
Low intensity cardio offers another unique benefit for fitness enthusiasts and athletes, too. Unlike other forms of activity, it’s very effective at increasing your stroke volume.
Stroke volume is the output of blood from the left ventricle with each heartbeat. Over time, endurance training enlarges the capacity of your left ventricle, increasing stroke volume[*].
And don’t worry about left ventricle enlargement. Keep in mind that the eccentric hypertrophy associated with aerobic training isn’t the same as unhealthy concentric hypertrophy.
Instead of compromising your heart function like concentric hypertrophy, a higher stroke volume makes your heart more powerful and efficient, resulting in better aerobic fitness[*].
The easiest way to assess stroke volume is by measuring your resting heart rate. A decreased resting heart rate correlates to increased stroke volume from training.
#8 Increased Force Production
Believe it or not, aerobic training can also increase your power production during “anaerobic” activities[*]. This claim may sound like a stretch, but it’s a proven fact.
Your body’s three primary energy systems (ATP-CP, glycolytic-lactate, and aerobic) map onto different levels and durations of exercise intensity.
The predominant energy system changes with intensity and duration, in other words.
But instead of being neatly separated, there is a significant overlap of energy system contributions in each duration and intensity zone.
Specifically, although ATP-CP has a limit of about 10 seconds of continuous work capacity, your type I muscle fibers and aerobic system also contribute as soon as you become active, including during this shorter, “anaerobic” duration of activity[*].
Essentially, by increasing your aerobic power output, you can also increase your power output for activities lasting less than 10 seconds, as well as intermediate (glycolytic) bouts lasting up to 2-3 minutes.
Studies confirm this fact in:
- Young people[*]
- Men of various ages[*]
- Older women[*]
- Elite track athletes running 200-1500m[*]
- Combat sport athletes[*]
The takeaway: if you value force production, power, or explosiveness, but haven’t trained aerobically recently, you may be able to boost your favorite athletic qualities with low intensity cardio.
And of course, even pure strength and power athletes can benefit from the fat-burning, health-promoting, and recovery-boosting properties of low intensity cardio.
There are plenty of different ways to do low intensity cardio, not necessarily one “best” way.
This section will help you make low intensity cardio work for your goals. Check out the next section (3 Sample Low Intensity Cardio Plans) for concrete, practical examples.
What Duration and Frequency Should I Use?
Here’s one of the inescapable truths of low intensity cardio: the longer the duration, the more benefit. This observation applies for fat loss as well as fitness purposes.
One thing LIC isn’t is a quick fix. Sorry–you can’t get amazing benefits in 4 minutes with low intensity cardio.
But as long as you have 30-40 minutes to dedicate, you’ll be amply rewarded. According to some research, sessions of 30 minutes or longer burn more calories and boost your fat oxidation more than shorter cardio sessions, even compared to shorter sessions of HIIT[*][*].
Between one and three LIC sessions per week, on the days you don’t lift weights or train hard, should be ideal for most people.
If you enjoy it a lot or want to get more fat loss and fitness benefits, you can increase session length to 1-2 hours. You’ll get double or quadruple the fat loss and other benefits of a 30-minute session, but without spending unsustainable amounts of time.
Because the upper ceilings of fitness and fat loss benefits are very high with low intensity cardio, advanced athletes and people who are experienced with fat loss may wish to experiment with much longer sessions for temporary periods.
What Intensity Level and How Do I Measure It?
Along with requiring an appropriately long duration, low intensity cardio can’t be overly intense. If it is too intense, you’ll hamper your recovery and burn less fat.
So how can you measure intensity accurately?
Here are the three best ways:
- Using a heart rate monitor
- Paying attention to your ventilatory thresholds
- Checking your pulse from time to time
For the first and third methods you’ll need to have a target heart rate in mind.
The 180 Formula and Standard Method of Heart Rate Reserve
Here’s everything you need to know about target heart rate.
World-renowned endurance coach Phil Maffetone recommends his 180 Formula instead of the standard heart rate method (which is (220 minus age) times 65-80%).
Using the standard method, a 40 year old (of any fitness level) would come up with a range of 117-144 beats per minute.
But Maffetone’s method is easier to calculate and more on the conservative side. Using the 180 Formula, you can be sure you aren’t overdoing intensity.
Here’s how to use the 180 Formula: subtract your age from 180. Then, subtract additional points for each of the following:
- Have a medical condition or take prescription drugs (10 points)
- Illness, injury, get sick often, allergies, asthma, or inconsistent or new to aerobic training (5 points)
And that’s your maximum heart rate for low intensity cardio according to the 180 Formula.
For example, a 40 year old who is new to aerobic training would use: 180-40-5=135 beats per minute for their maximum. (Notice that’s much more conservative than the standard heart rate formula, which gave us a max of 144 bpm.)
Keep in mind that with a lower heart rate you’ll be slow at first, but as you get more aerobically fit, your speed or work rate will increase as your target heart rate remains the same.
And you can recalculate your 180 Formula target heart rate whenever your circumstances change.
For people under 17 or over 65, Maffetone recommends different approaches. Fit people 65 and up may need to add 10 points to their 180 Formula result, while athletes 16 and under may do better with a target heart rate of 165 bpm.
Ventilatory thresholds (VTs) might sound technical, but in reality they’re easier than using a target heart rate to gauge intensity, and research shows they may yield equal (or even better) results[*][*].
These thresholds describe your relative ease or difficulty speaking during exercise.
In a nutshell, your aerobic energy system requires ample oxygen to provide your cells with energy. The harder you train, the higher the oxygen demand, which eventually results in an oxygen shortage.
And when you don’t have enough oxygen, it gets much harder to speak!
You have two ventilatory thresholds, the first (VT1) and second (VT2). They correspond to exercise intensity because they represent increased oxygen demand and lactate accumulation.
Here’s the breakdown:
- Under VT1: Speech is easy, no difficulty speaking comfortably in complete sentences.
- At VT1: Some difficulty speaking in complete sentences appears.
- Between: Difficulty and noticeable discomfort of speaking in full sentences increases.
- At VT 2: Only one or two consecutive words are possible.
- Over VT2: Speaking is impossible.
Using VTs to manage your cardio intensity is easy: the upper limit of low intensity cardio corresponds to VT1, or just below it[*].
In other words, you can try to speak a full sentence or two to gauge your training intensity. If you are experiencing little or no difficulty or discomfort speaking in full sentences, you’re still doing low intensity cardio.
If it’s uncomfortable to speak in full sentences, scale back the intensity until you can again.
Nose-Breathing as Autoregulation
Heart rate measures and the VT test each provide a form of autoregulation to keep your efforts at the correct intensity.
But not everyone has a heart rate monitor, and the VT method or pulse readings are only a snapshot–they’re not “always-on” solutions.
Fortunately, there’s a simple way to continuously autoregulate without collecting extra gadgets.
Here it is: breathe through your nose. If you find yourself unable to nose-breathe comfortably, slow the pace drastically until you can calmly and comfortably do it again.
Research shows this level of cardio intensity fits into the aerobic zone, making it perfect for low intensity cardio[*].
Nose breathing during exercise also increases your nitric oxide levels up to double compared to mouth breathing[*]. Nitric oxide is a heart-healthy signaling molecule that can lower your blood pressure, improve your stress response, and even help boost your mood[*].
One study even found that nose breathing while running improves running economy over time compared to mouth breathing, and can improve performance by 3% or more[*].
Hydration and Cardiac Drift
If your heart rate goes up higher than usual, you may be dehydrated.
One study found that mild and moderate dehydration can increase your heart rate by around 10-20 beats per minute for the same work rate, as well as reduce stroke volume[*].
These findings are especially true of prolonged sessions, or for people who train in hot climates.
In a nutshell, if you’re sweating a lot, you may need to rehydrate to get optimal results from low intensity cardio.
How to Choose Your Method and Select Your Exercises
Before you decide which exercise or exercises to use, you need to decide which of the following your low intensity cardio session will be:
- Steady state training
- Interval training
- Circuit training
As long as you stay within the appropriate intensity range, each method is equally useful for attaining the benefits of low intensity cardio.
You can mix and match, too, although it’s best to be consistent long enough to gauge your results.
Low Intensity Steady State (LISS) Training
Steady state training is the simplest way to do LIC, and is best suited for traditional aerobic activities like running, hiking, swimming, and cycling.
It may not be the most interesting, but it’s simple and suitable for nearly everyone.
Low Intensity Interval Training
Interval training works with the above exercise choices, too.
In a nutshell, pair up a more-intense and a less-intense form of exercise together, like running and walking, skipping rope and walking, or hitting a heavy bag and doing loaded carries.
As long as your intensity doesn’t exceed the upper limit, you’re doing low intensity interval training.
Aerobic Circuit Training
The possibilities of interval training are virtually endless, but circuit training is an even greater opportunity to be creative.
This seldom-used training method calls for nonstop aerobic work using a continuous circuit of various movements.
You can use light resistance exercises, bodyweight movements, and many different types of equipment.
Whichever exercises you choose for low intensity aerobic circuit training, they must be:
- Spread over two or more major muscle groups (no isolation type movements)
- Safe to perform fatigued (so no Olympic lifts, for example)
- Possible to perform at lower intensities (no heavy loading or max effort)
Put differently, you need to choose “functional” or nearly-full-body movements that won’t hurt you with a minor lapse in form, and that allow relatively lighter loads or speeds–never heavy or maximal.
And unlike interval training, your circuit training movements should all be nearly equivalent in intensity.
Keep reading to see some real-world examples of these different methods in action.
Public Service Announcement: Move Well
For now, one more thing to keep in mind: every time you perform a movement at any intensity, you’re teaching your body how to move in the future.
Therefore, think of low intensity cardio as the perfect opportunity to work on impeccable movement quality. Along with everything else it offers, it’s also an extended movement practice session.
But the flipside is that you need to know the fundamentals of a movement before you can practice it effectively (to get better at it and avoid injury). This insight is even true of common choices like running and cycling.
Basically, if you’re new to a specific movement, don’t incorporate it into workouts until you’ve learned how to perform it correctly. That way, you’ll improve your movement skills and stay injury-free.
Do I Have to Warm Up?
You may get better results by warming up for 5-15+ minutes, but you don’t have to do it.
Some evidence suggests warm-ups don’t aid performance in aerobic exercise very much or at all[*].
If you choose to warm up, try a vigorous walk followed by an even lower intensity of your low intensity cardio exercise(s) for the day. Then do the full-length cardio session you’ve planned.
But if you’re not concerned about total optimization or minimizing your injury risk fully, you can do your low intensity cardio without a warmup or cooldown.
Compared to most forms of exercise, it’s much closer in intensity to a warmup anyway, so that’s not such a bad idea as, say, doing a max deadlift with no warm-up.
You can try both ways, or warm up and cool down when you have the extra time.
Cardio Before or After Weights?
It just so happens resistance training and low intensity cardio are a match made in heaven.
Resistance exercise gives you:
- Ample stimulation of your anaerobic ATP-CP energy system and type II (“fast-twitch”) muscle fibers
- More EPOC than HIIT or low intensity cardio[*]
- The ability to preserve lean muscle mass when you lose fat[*]
While low intensity cardio helps to:
- Train your aerobic system, resulting in a healthier heart
- Speed up recovery from resistance training[*]
- Accelerate fat loss and make losing fat easier[*]
As you can see, you get plenty of non-overlapping benefits from each style of training.
And a combination of the two appears to result in more belly fat loss than either one individually[*].
However, you can’t just combine them willy-nilly and expect first-class results.
According to some research, the ideal schedule for fat loss is to lift and do cardio on separate days[*]. This schedule may also encourage recovery from weight training compared to more compressed schedules[*].
But if you have to do them on the same day for scheduling reasons, it’s best to do your weight training first.
You’ll deplete more glycogen that way (meaning more fat-burning during cardio, relatively speaking), you’ll have better performance during resistance training, and the post-lifting cardio can help reverse any arterial stiffness caused by lifting[*][*][*].
Fasted Cardio vs. Fed Cardio?
So you’d never want to compete fasted, but athletes and people working on their fitness can still benefit from some fasted low intensity cardio training[*].
If you already fast each week, you can try scheduling in some LIC during your existing fast windows.
And if you aren’t fasting yet, read more about intermittent fasting here. However, even a low intensity cardio session before breakfast (without a prolonged waking fast) increases fat oxidation for a full 24 hours[*].
Bottom line: most people will get better results doing all their low intensity cardio fasted, but if you don’t fast, you can still benefit from LIC.
You only need to do your low intensity cardio and aerobic training fed if you value session performance above fat loss, and even then, not every time you train.
To be effective, any low intensity cardio program needs to provide both challenge and enjoyment, plus periodization so that it works for more than just a few weeks[*].
If you aren’t sure how to do that, use any of these plans to strike the proper balance. And remember to have fun!
No matter what you decide, keep in mind that autoregulation (from using VTs or a heart rate monitor) offers a gentle form of progression, so you don’t always need to increase volume or work rate to progress.
Using autoregulation, you may be able to progress (cover more distance or do more work)–even using the same frequency, intensity, and duration–for weeks or months.
But if you get bored or your results get stale, it’s time to try something new.
When you finish one plan, you can move to another or adopt a similar approach with reduced volume to maintain your aerobic fitness gains going forward.
#1: Fasted Low Intensity Cardio
This program is the perfect way to accelerate fat loss as long as you’ve already dialed in your diet.
It’s simple, without any frills, but you do need to be able to fast safely and comfortably to get the most out of it. If you can’t fast for whatever reason, though, you can still benefit.
Duration: 8+ weeks
Exercise options: Running, cycling, hiking, swimming, or any steady state activity of appropriately low intensity.
Best for: Fat loss, aerobic fitness
Weeks 1-2: Two weekly sessions of 30 minutes each.
Weeks 3-4: Three weekly sessions of 30 minutes each.
Weeks 5-6: Three weekly sessions of 45-60 minutes each.
Weeks 7-8: Four weekly sessions of 45-60 minutes each.
Perform all cardio sessions fasted if possible. You can do them right when you wake up, or any time during your fast window.
If you aren’t fasting, at least avoid carb meals the days you perform low intensity cardio. As we covered earlier, carbs can inhibit fat burning even after your insulin levels return to normal.
Use the 180 Formula or ventilatory threshold method to gauge your intensity. Nose breathing is optional.
#2: Low Intensity Interval Training
Interval training is a fantastic way to increase your aerobic fitness. And if you’re new to exercise, it may be easier on your body than steady state cardio.
Duration: 12+ weeks
Exercise options: Running, cycling, swimming, or any activity or activities that allow both “easy” and “moderate” pacing. For example, running and walking, or swimming slower and faster.
Best for: Aerobic fitness, fat loss, cardio beginners.
Weeks 1-3: Two weekly sessions of 30 minutes each. Go “easy” for 4 minutes, “moderate” for 1 minute, repeat until finished.
Weeks 4-6: Two weekly sessions of 30-45 minutes each. Go “easy” for 3 minutes, “moderate” for 1 minute, repeat until finished.
Weeks 7-9: Three weekly sessions of 30-45 minutes each. Go “easy” for 2 minutes, “moderate” for 1 minute, repeat until finished.
Weeks 10-12: Three weekly sessions of 30-60 minutes each. Go “easy” for 2 minutes, “moderate” for 2 minutes, repeat until finished.
“Easy” and “moderate” are relative to your fitness levels. Both still need to fall within the intensity levels we discussed previously (whether you use a heart rate monitor, your pulse, or ventilatory thresholds).
If you are running intervals at “moderate” pace, your “easy” pace is walking. Therefore, if you aren’t running, your best “easy” option will be a very slow version of the activity you’re using.
Or you can also pair up two different activities if you prefer.
But either way, don’t confuse low intensity intervals with HIIT. Track your chosen measure of intensity carefully.
That said, you may find you can work harder at intervals compared to steady state and easily stay in the low intensity zone–which is one reason intervals work so well to enhance your aerobic fitness.
For time management, use an interval training app or a gadget like a GymBoss instead of looking at your phone clock or watch.
#3: Aerobic Circuits
Try aerobic circuits if you want to boost your functional fitness and enhance your recovery, or if you dislike traditional cardio exercises. Circuits are also a fantastic, space-efficient way for two or more people to train together.
And if you want to enhance your sport-specific aerobic fitness, you can use a similar template to this one, but with movements that are relevant to your sport.
Duration: 6+ weeks
Frequency: 2-3 times per week
Best for: Functional aerobic fitness, active recovery, people who dislike traditional cardio
Circuit A (2-3 minutes each):
Loaded carries (farmer’s walks or various others)
Medicine ball throws or slams (choose one or combine them)
Rowing machine (optional)
Sled pushing or pulling (optional)
Battle ropes (optional)
Circuit B (30-60 seconds each):
Standing broad jumps
Dumbbell or kettlebell goblet squats
Hinge-to-wall drill (like a deadlift without weight, making your glutes touch the wall or object behind you each time)
Push up position plank
Zig-zag running (use cones if possible)
Medicine ball slams
Perform Circuits A and B once each week on separate days, or alternate the circuits if you do more than 2 weekly sessions. As long as you can perform most of the exercises, don’t worry if you lack some of the necessary equipment.
Go through each circuit with no rest, minimizing downtime, but adjusting the pace as needed to stay aerobic. Repeat until you’ve completed the session.
Begin with 30-minute sessions. Add 1-5 minutes per week to all sessions.
For knowing when to change stations, use an interval training app or a gadget like a GymBoss instead of looking at your phone clock or watch.
Make sure to use impeccable form on all movements.
Use the 180 Formula or ventilatory threshold method to gauge your intensity. Nose breathing is optional.
Low intensity cardio offers health and performance benefits for all types of people and athletes, regardless of health history or age.
However, it’s always advisable to speak to a physician before starting a new exercise program. This precaution is especially important if you’re currently sedentary, have a health condition, take prescription drugs, are a senior citizen, or are pregnant.
Consider low intensity cardio if you want:
- More overall fat loss
- Increased belly fat loss
- Enhanced aerobic fitness (which can enhance short-term power output, work rate, and heart rate recovery, among other benefits for anaerobic athletes)
- Long-term health benefits
Finally, as we discussed earlier, just because you can burn fat for hours upon hours with low intensity cardio, doesn’t mean you should.
While extremely high-volume cardio can be a great short-term way to accelerate fat loss for some people, it’s not a sound long-term approach.
In fact, excessive cardio can be one manifestation of anorexia. If you think you may have an eating disorder or body image disorder, speak to a doctor or counselor.
For everyone else, be patient, make sure your diet is on point, and don’t push into the double digits with your weekly low intensity cardio hours regularly or for very long.
Every exercise intensity offers unique benefits, but low intensity cardio doesn’t get enough respect.
The research-backed and remarkable fat loss, health, and fitness benefits all make aerobic training worth your time.
HIIT may continue to steal the show in an impatient and headline-focused fitness world. Still, if you slow down and try LIC for a few weeks, you can experience greater relaxation, faster recovery, elevated fat-burning, and more for yourself.
To date, the highest fat-burning rates ever measured have occurred in keto-adapted endurance athletes[*][*]. Therefore, if you want to maximize fat burning, keto and aerobic exercise are the best pairing for you.
Finally, keep in mind that low intensity cardio makes your results better, but you still need a wise approach to diet, strength training, and supplements to get optimal results for fat loss, fitness, and health.