By Myprotein Writer
This article will cover why low intensity steady state (LISS) cardiovascular training may be undeserving of the hate it gets. I will cover evidence that shows that LISS cardio does not cause fat gain, compare low intensity cardio over other forms of training and show how to implement it to benefit other training methods.
Just so we’re clear - cardiovascular training is the lower intensity, repetitive movement training that often involves many muscle groups at once - think running, swimming, cycling and skiing!
LISS Cardio and the Fat Gain Myth
Cardio doesn’t inherently make you fat (,,)- but over eating calories relative to your expenditure does. Even if you do no cardio at all, if you eat too many calories then you will still get fat. The opposite is also true: even if you did cardio, but didn’t eat enough calories to replace the energy used, then you would lose weight.
Some people believe that cardio decreases your metabolism and therefore causes people to gain fat in the long term. Research seems to show that cardio doesn’t in fact directly decrease your metabolism (). Having a lighter body with less muscle may just do that though (5), so we can see where this argument comes from. If we were to weigh less, then the calories needed to maintain weight (and to gain weight), would be fewer, thus our metabolisms would be ‘lower’.
Cardio Calorie Burn
Cardio tends to be very good at using up calories as it can be performed for a long time at a relatively high intensity. This means that cardio can easily cause a caloric deficit (when we eat fewer calories than we burn).
When we have a caloric deficit our bodies need to come up with the energy from somewhere. This is where the body’s own energy stores come in - both fat and muscle tissue is a store for energy. Thus it’s only because cardio is so good at reducing stores of energy (and thus causing weight loss) that it could have the effect of reducing metabolism.
If we were to eat enough to replace these lost calories, then our metabolisms would not drop - because we would not lose size. Even if you lost weight from doing resistance training, your metabolism would still drop!
More calories for better cardio performance?
Some people try to eat more calories in order to boost their cardiovascular performance. Though I don’t disagree with doing this, this is a possible reason why some people think that cardio causes fat gain.
Muscles are made up of both ‘type I’ and ‘type II’ fibres. Type I muscle fibres are slower to grow, and have a smaller max size potential that type II muscle fibres. Cardio preferentially causes growth in type I fibres whereas resistance training preferentially grows the larger type II fibres (you wouldn’t do cardio to try and build hefty muscles).
Adding extra calories to improve performance can therefore result in fat cell hypertrophy as the type I fibres are more likely capped out in terms of growth - even if they aren’t they will grow slower and have a lower demand for energy (therefore more food will be shuttled to storage cells).
No weight loss with LISS cardio?
Like all exercise, cardio causes stress, which can have notable temporary effects on the body. Stress on the body can cause higher levels of cortisol to be found in the blood stream. Stress also raises binding affinity of cortisol to water weight regulation receptors - which then makes cortisol mimic the effect of aldosterone and causing water to be retained at a higher rate ().
This can confuse some people as they feel that they are putting on weight (or at least not losing any) when they do ample amounts of cardio and are in a caloric deficit. If they do excessive amounts of cardio, and are in a large caloric deficit, then they will be extremely stressed - causing more water weight gain than someone who is in a smaller deficit and does less cardio.
As water weight is temporary, there is no need to panic at this initial apparent ‘weight gain’ or ‘weight loss plateau’- you are still burning fat and when you cease dieting (or reduce the amount of exercise you do), this water weight is likely to fall off rapidly!
Benefits of Low Intensity Cardiovascular Training
One study found that cardio was as good as resistance training in maintaining metabolic rate (). This is important as dieting and weight loss causes your metabolism to slow down (the body has strong incentives to not burn up its life saving fat stores with a high metabolism).
When talking about the ‘After Burn Effect/EPOC’ (Excess Post Exercise Oxygen Consumption) from high intensity training, calories burned post workout increases linearly with time (in other words- the longer the session, the more calories burned post workout at a static rate) and exponentially with effort (harder workouts will burn disproportionately more per time spent exercising).
This sounds great; work really hard and you’ll burn more calories off in the long run, but just how many?
Unfortunately, even with extremely hard workouts, EPOC only amounted to several 10s of kcals burned. The authors then concluded that more effort should be spent trying to burn calories during the session (a hard running session can burn 500kcals per hour) rather than attempting to increase the after burn calorie burning effect for hours after the session ().
What this means is that the argument that doing high intensity training burns more calories than low intensity training is not wholly correct. HIIT does burn more calories per minute, but cannot be done for as long as LISS (have you tried to sprint for an hour straight?).
LISS training is also much easier to recover from, meaning that we can engage in fat burning training more often and as a result burn fat quicker. HIIT can also impair resistance training, as it is done at a high intensity and can interfere with recovery (if done intelligently, with adequate recovery, then HIIT would benefit resistance training).
If time were limited, then obviously HIIT would be better than LISS as you would be training at a higher intensity and would not have the extra time to make up for calories burned (as LISS over a longer duration would).
LISS v HIIT Summary
The reason why weightlifting or high intensity training may cause you to be able to eat more calories without gaining fat is that muscle can take a hefty amount of energy to build, and a bigger body means that there is more metabolically costly tissue to maintain.
What we should draw from this isn’t that high intensity training is useless (in fact, it is a great way to improve fitness, retain or even build muscle - especially if time exercising is limited), but that LISS isn’t useless either.
? HIIT is pretty difficult to recover from, whereas LISS tends to be easier. We could therefore use LISS training much more often than HIIT.
How to Implement LISS
This section will try and sell you on why you should include some LISS training in your routine (especially if you do not do any other forms of cardio) and how to do so!
LISS training done appropriately should not detract from your efforts in other training sessions, and can even increase your efforts in the weights room! Improving your cardiovascular system can increase your work capacity - meaning that you can lift for longer. This will enhance the effect each session has.
Think about it: if you can perform 6 sets of 10 squats - where you used to be only able to do 3-5 - then you will get a bigger growth stimulus.
? LISS can help with HIIT too: by being able to recover more quickly (as your heart is better able to pump nutrients to your muscles, and you lungs are able to work harder to oxygenate them), you will be able to do more high intensity sets, and with shorter rest intervals (thus increasing your total time spent doing your high intensity intervals, and increasing your average heart rate throughout- burning more calories!)
How should you implement it, then?
Try to build up to a base of 20 minutes of steady state cardio at 60% maximum heart rate (MHR).
We are going to use running in this example, but you can cycle/swim/row/ski to your heart’s content, and we will try to build up our conditioning by mixing running with walking whilst we slowly increase the time we send running and slowly decrease the time we spend walking.
To estimate your max heart rate: 220-Age.
? To build up to this (if you are unable to do it already), mimic interval training by running at 60% for 2.5 minutes, and then walk and recover for 1 minute. Do this 5 times.
? Over time, try to increase the time you are running for (for instance, you could increase each running interval by 15 seconds every session) and decrease the time you are resting/walking (for example you could go from 5 sets of 2 mins running/1 min walking to 5 or even 6 sets of 2:15 running/ 45 seconds walking.) This example of run/walking is hugely successful for many people and forms the basis of the popular ‘Couch to Five Kilometres’ program (‘C25K’).
? Eventually you are going to phase out the rest intervals (the walking intervals) completely, and end up with a continuous run for the entire.
Once you have this base (probably around 15-20 minutes), you have several options for progressing.
1) You could increase the intensity of the run (by increasing your target MHR- say 65-70%), or you could go for extra time spend running. If you go the second route, you could increase the time spent running by 2 minutes every session (this rate of increase will decrease over time).
2) If you go the former route, just be careful that you do not increase the intensity too much that it becomes a max effort HIIT (without the interval) run that messes up your recovery and leaves you shattered the next time you hit the gym.
3) You could even mix and match, by having a ‘faster/intense’ run earlier in the week and a ‘longer/volume’ run later on- be creative.
Take Home Message
LISS training isn’t as bad as it's made out to be, and definitely doesn't cause fat gain.
Low Intensity Steady State cardio is actually a great way to burn fat if you have the time, and it can even increase the benefits of resistance training!
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 Song, J.K., et al. (2012), Effects of 12 weeks of aerobic exercise on body composition and vascular compliance in obese boys. Journal of Sports Medicine and Physical Fitness, 52 pp522-529
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 McCormick, S.D. and Bradshaw, D., (2006), Hormonal Control of Salt and Water Balance in Vertebrates. General and Comparative Endocrinology. 146 pp3-8
 Broeder C.E., et al., (1992), The effects of either high-intensity resistance or endurance training on resting metabolic rate. American Journal of Clinical Nutrition, 55 pp802-810.
 LaForgia J et al., (2006) Effects of exercise intensity and duration on the excess post-exercise oxygen consumption. Journal of Sports Science. 12 pp1247-64.
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Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you're concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.