Endurance is a word tossed around lightly, often interchangeably with another word “stamina”, though they aren’t the same. It seems like everyone wants to improve their “endurance”, but have absolutely no plan, or even the slightest clue as a matter of fact, how to go about doing so.
Consider this your definitive source for all that endurance encompasses; after you’ve digested all this content you will be capable of giving lectures yourself!
Have you ever had to endure something? What did it entail? Considering this analogy helps make the understanding of endurance a bit clearer.
Endurance refers to the measure of an athlete’s body to tolerate sustained intensity work over a prolonged period of time.
Thus, having to deal with your angry boss on a daily basis builds your endurance. Or more appropriately, training helps one to develop adaptations that increase the duration of work while simultaneously buffering fatigue.
It is important to note that endurance is not about exerting maximal effort; rather, low to moderate-intensity activity over an extended period of time.
Stamina, on the other hand, is about exerting maximal output for as long as possible and is usually under two minutes in duration. A bodybuilder, attempting to squat 400lbs to failure is actually testing his stamina. At the point of failure, it isn’t immediately possible to perform even one more repetition.
The same can be said for sprinters who partake in a maximum intensity dash to the finish line. Sprinters can’t keep this up indefinitely, which is why such races are brief. It would be impossible to find someone sprinting through a 10K race.
Endurance is all about the end goal. You aim to cover 5 miles today, there is no pre-defined notion of when you need to complete it or how fast you need to move. The key thing is being able to complete the entire distance, and eventually, doing more.
If you are able to run for 30 seconds now, and then make it to 15 minutes 60 days from now, then your endurance has improved.
There is a simple tried and true approach when it comes to increasing your endurance; you must practice your discipline. Endurance will not improve if you are not training enough. This, however, does not mean that you can blindly start working out. Without a plan, you won’t see better endurance.
Depending on whether you are trying to up your muscular or cardiovascular endurance, you will be required to work on various aerobic or anaerobic types of activities.
Aerobic activity improves your VO2 max and in turn, will raise your anaerobic threshold.
In order for you to truly take your endurance to the next level, you must become aware of the “limiting factors”, so to speak. the good news is that most people can improve endurance over time. But first things first, let’s look at what these factors are.
You may have heard from seasoned athletes the talk of VO2 max, but what exactly is that? Also referred to as maximum oxygen uptake, VO2 max is a measure of the maximal rate at which oxygen can be transported by the blood[i].
Historically, an endurance athlete’s VO2 max was believed to be the factor that would determine overall “success”, but this stance has been changed as the understanding of the physiology of endurance has evolved.
However, this does not mean that low VO2 max equals high performance; it just signifies that you do not need to be the absolute highest in the room to be the best. An athlete with a lower VO2 max is very capable of outperforming someone with a higher VO2 max.
The anaerobic threshold, in comparison, has superseded aerobic capacity as the primary determinant of how successful you will be in a race, as the best athletes are able to perform at a high capacity of their VO2 max, while less seasoned athletes cannot.
For instance, well-conditioned runners may be able to sustain between 80 to 90% of their VO2 max, while still being able to buffer lactic acid and positively charged hydrogen ion accumulation. When this anaerobic threshold is surpassed, the rates of muscle contraction slow significantly, leading to fatigue or muscle failure.
Improving your anaerobic threshold is important as it is what sustains high-level performance over an extended period of time (what we otherwise call the race speed).
Whereas your aerobic energy system is efficient at using fat to produce the energy required to maintain low-intensity performance, the anaerobic system utilizes carbohydrates in order to maintain a higher level of performance.
Improving your anaerobic threshold can mean the difference between you qualifying for that big race or not.
While this notion may seem foreign to amateur athletes, it makes perfect sense when you think about it. Do you think your body performs more efficiently with you running a slow controlled marathon or a hectic race with arms flailing all around? This is a good way to appreciate the meaning of an economy of motion.
Elite-level athletes can actually utilize as much as 15% less oxygen than their amateur counterparts who simply waste fuel and oxygen on activity that does not improve speed[ii]. Simple modifications such as keeping your torso relaxed and not rigid, or preventing excessive movement while cycling can all lead to appreciative changes in overall performance.
Having just briefly discussed the anaerobic threshold, now it is time you see the relationship with food consumed. At faster race speeds, as the body approaches its anaerobic threshold, your reliance on glucose for energy increases[iii]. This effect is particularly noticeable in naïve athletes.
As your conditioning improves, and your anaerobic threshold increases, your body becomes more efficient at using fat to power performance that is at a submaximal level.
To clarify, elite athletes that have anaerobic thresholds that are 90% of their VO2 max will continue to utilize fat for energy production as high as the 80% VO2 threshold.
Lesser trained athletes will not possess as high anaerobic threshold, and thus, are more reliant on carbohydrates to perform at race speed. The big limitation with this, however, is the fact that carbohydrate stores are much more quickly used up during a race.
Fat stores are much more abundant and lend themselves to being an efficient fuel source over the long haul.
If you recall, there are broadly two types of muscle fibers which were referred to as type I and type II (even though there are actually three subtypes of type II muscle fibers). To understand how and which muscle fibers play the Greatest role in endurance performance, it is worth the time to familiarize yourself with their characteristics.
Let’s simplify. Type II fibers are generally referred to as fast-twitch fibers and are usually recruited at the inception of physical activity when muscle glycogen is highest and fatigue is low. This is, however, assuming that the athlete starts out at a higher intensity and gradually slows to a consistent pace.
Think of Olympic sprinters. They generate immense force and speed out of the gate, but cannot sustain this peak level of performance for very long. This is why there is no 2000 m sprint; type II muscle fibers become fatigued much sooner than this.
Type II fibers generally possess fatigue resistance that is moderate at best, so taking for example a weightlifting session, you may be able to perform a moderate number of repetitions with 70 to 80% of your one-rep maximum.
Type I fibers, on the order hand, are all about the long game[iv]. They possess the highest numbers of muscle mitochondria within their cellular organelles and are excellent at keeping up the pace of energy production at submaximal levels.
Type I muscle fibers are involved largely in the aerobic energy production pathway, and they are also very fatigue resistant. An elite level marathoner with a high anaerobic threshold will be able to maintain a very good race pace throughout the run.
Your body is a marvelous construction of intricate machinery that works even better with exercise. This is very true as it makes several adaptations to endurance training that promote one’s quality of life. For instance, you may observe the following changes as your endurance improves:
Many people do not understand the principle of heart rate. In normal people (normal referring to the majority of the population that exercises about three days per week at a low to moderate intensity), the resting pulse may vary between 80 to 120 beats per minute. This isn’t usually alarming.
As endurance improves, the first thing that may be observed is a decrease in resting heart rate.
This is not a reason for panic. It is, in fact, a very good thing. A reduction in heart rate usually coincides with increased stroke volume-or the amount of blood ejected by the heart with each contraction (heartbeat).
A larger stroke volume means that the heart is able to supply more blood with fewer beats, albeit with greater force of contraction. The hearts of many trained endurance athletes also display cardiomegaly, or enlargement but in the absence of a diseased state.
Someone who goes from sedentary to fairly active may be able to reduce their resting heart rate by as much as 1B per minute weekly for up to 10 weeks (and the maximum of 10 beats), although the average is probably closer to a five-beat reduction.
It should go without saying that there is a noticeable change in body composition in well-trained endurance athletes when compared to the average population. This occurs for a few straightforward reasons.
First off, there is the increased usage of fat for fuel. This in itself will decrease adipose stores, sometimes noticeably. You will hardly notice an overweight or obese endurance athlete that has been training for a decent amount of time (although there are exceptions).
It is a well-established fact that regular endurance training increases the number of mitochondria within muscle cells. This is a positive development, but there is also another lesser-known mitochondrial adaptation that occurs gradually; an increase in the oxidative potential.
The oxidative potential of the mitochondria is better known as the ability to produce energy, with trained athletes being able to produce approximately 25% more ATP than non-trained athletes.
This occurs in combination with up to a twofold increase in the number of actual mitochondria within the muscle cells[v].
Occurring hand-in-hand with the increased rate of oxidative capacity of the mitochondria is an increase in capillary density, measured as the amount present per cross-sectional square millimeter size area of muscle fiber.
The main purpose of capillaries is to facilitate oxygen transport to the working muscles, so it makes sense that in order for the aerobic capacity to increase, a greater amount of oxygen must be delivered via the capillaries-usually accomplished by an increase in their number.
The exact amount, or rather ratio, of one muscle fiber type to another is not set-in-stone for every human. This is because there are small differences owing to genetic factors, which is why some people gain muscle mass easier (which usually indicates a higher proportion of type II fibers), and why others may excel at endurance type activity.
In general, however, there is a consensus that endurance athletes will be able to shift the balance of type I to type II fibers more to the right, as one can possibly alter the overall proportion of these fibers[vi] by around 10%.
Thus, to compensate for the needs specific of endurance athletes, a greater proportion of type I slow-twitch fibers persists. It is important to note, however, that these changes are not permanent and depend on continuous activity to remain. This is a very real example of use it or lose it in action.
Changes to both the aerobic and anaerobic energy production systems manifest from endurance training, as was briefly mentioned in the factors that affect endurance. VO2 max improves over the course of several weeks, which is an excellent measure of aerobic capacity.
In a similar fashion, an improvement in aerobic capacity or VO2 max will also have the net effect of enhancing the anaerobic threshold. This is because you will be able to perform at a high-intensity (the threshold) for a longer period of time before fatigue sets in. Anaerobic metabolism occurs in the absence of oxygen, usually reserved for intensities beyond that of aerobic respiration.
There is a definite known association between aerobic activity and optimizing your cholesterol profile. Optimizing refers to a general reduction in LDL levels and a simultaneous increase in HDL, while also keeping triglycerides low.
Endurance exercise may help support healthy HDL levels when performed beyond 75% maximum heart rate, as below this point the beneficial effect is not observed.
There is also increased expression of enzymes that enhance transport and clearance of cholesterol from the blood. This is why, even while under treatment with prescription medication, aerobic dominant exercises are advised.
Endurance activity, characterized by the abundance of aerobic activity, usually coincides with improved insulin sensitivity. Under anaerobic conditions, this improvement may be greater, although there is mixed evidence as to the frequency and duration of activity necessary for the change.
In addition to this, is the proven fact that endurance-type activity increases glucose uptake in muscle cells by up to a factor of 50, and via a non-insulin mediated mechanism (GLUT4 system). This means that even in the presence of insulin resistance or diabetes, glucose levels can still be controlled with such exercise.
Endurance does not refer to just the skeletal muscle endurance, but also the cardiopulmonary system. Let’s check out what the major differences are.
Muscular endurance is a necessary pre-requisite if you wish to become a world-class athlete. Simply put, it is the ability of the skeletal muscle to continually contract or perform an activity over a long period of time.
A higher level of muscular endurance means that you will be able to maintain performance for an extended period of time, which could translate to longer runs in your next race.
The only way to actually improve your endurance is via training. Not just randomly picking up weights in the gym or going for long leisurely strolls on the beach – but rather a proven and systematic way that works.
Muscular endurance responds best to low-intensity strength training, usually at around 50% of the one-rep maximum. Each working set may be performed for between 15 to 25 repetitions.
When it comes to races, a good way to gradually build up muscular endurance is to increase the distance or duration traveled. Be sure to also maintain a relatively low intensity – the goal here is not to set a personal best but rather make your muscles more tolerant to work and resistant to fatigue.
A good muscular endurance program, depending on which approach you take, should be performed about 2 to 3 times weekly. This is because meaningful adaptations of training are additive – you must expose a working muscle to stimuli at regular intervals. Training just once weekly is not enough to elicit meaningful changes to muscular endurance.
While any activity could lend itself to improved muscular endurance, a few appear better suited than others. Planks are one such exercise that excels in this regard. By forcing the muscles to hold a static state of contraction, one can experience all over improvements to muscular endurance.
Dumbbells also lend themselves to a wide variety of body part-specific training which can be tailored from moderate to high rep ranges.
Walking at a moderate pace or jogging is also very effective at bolstering endurance. Just keep in mind that your goal is to make the muscles more tolerant to working for extended periods of time before fatiguing.
Regardless of the specific activity chosen to improve muscular endurance, it is also important to keep rest periods very brief – your goal is not to kickstart recovery and hypertrophy, but instead to give the working muscles a preview of the long task ahead.
Strength training programs for endurance athletes are a little different from those geared more for power and hypertrophy. Considering the use of barbells and dumbbells for the purpose of this discussion, a good program might look like this:
The fascia is a thin but strong muscular sheath that encapsulates muscles. Relaxing and loosening the fascia prior to strength training is a worthwhile endeavor, as it can support an enhanced range of motion, reduce injury and also promote better blood flow.
To do this, foam rollers or even tennis balls gently rolled over the target areas being focused on can help make muscles and other soft tissue ready for subsequent movement.
Dynamic stretches are performed following myofascial release as a way to promote elongation of muscle tissue that is involved in the full range of motion of the particular exercise. For example, walking lunges can help to elongate hip flexors to reduce stiffness, whereas downward facing dog helps to elongate muscles of the chest and shoulder regions.
If you’re not careful it is easy for rest periods to get out of hand, causing you to lose one very important aspect of building endurance- time. For this reason, it may be a good idea to fashion a resistance training program in a circuit-style manner.
Circuit workouts are great because they include brief rest periods and are very time efficient. Some excellent exercises to include in your circuit might follow this pattern; dumbbell squats – deadlifts – upright rows – floor press-ups – low dumbbell rows – planks.
Depending on your fitness level, aim to repeat this circuit 3 to 5 times at higher given rep ranges of between 15 to 25, or at least 50 seconds duration.
Strive to keep your main workout under 30 minutes.
A cooldown period consisting of static stretches and even more myofascial relaxation techniques are the perfect tools needed to kickstart recovery and also prepare your body for subsequent sessions. It can also contribute to reduced frequency of injuries or pain post-workout.
Cardiovascular endurance refers to the level of efficiency with which your cardiopulmonary system (heart, lungs, and blood vessels) is capable of delivering oxygen to working muscles that need it. Cardiovascular endurance is regarded as a good indicator of a person’s overall fitness or general health, as low endurance often coincides with a sedentary lifestyle and increased risk of morbidity or mortality.
Even modest improvements to cardiovascular endurance can have profound benefits on your sense of well-being, reduce tiredness, and also contributes to positive muscular endurance.
One excellent way to know if your cardiovascular endurance is high is to not feel out of breath at increased heart rates. For instance, if you go up a flight of stairs and feel winded while your heart beats out of your chest, this is a sign of poor cardiovascular endurance.
The best way to improve it is to challenge your cardiorespiratory system with activities that increase heart rate to the target heart rate zone[vii]. To calculate your maximum heart rate, subtract your age from 220.
Next, is determining your ideal target heart rate zone. For aerobic workouts, this target zone is 70-80% of your maximum. Maintaining the target heart rate (with the use of a monitor such as a wearable fitness tracker, for example) is a surefire way to improve your cardiovascular endurance.
The Centers for Disease Control and Prevention recommend a minimum of 150 minutes of physical activity per week[viii], performed at a moderate activity. If you are a dedicated athlete, you will likely surpass this number very easily.
In terms of aerobic activity, shoot for 3-5 times weekly. It is also necessary to perform the activity for 20-60 minutes per session for best effect.
Since improving cardiovascular fitness relies a lot on you sticking to your target heart rate zone, you won’t get much better if you casually stick to the low end of your max. You need an activity that challenges you. A few of these include:
Improving your endurance via running can revolve around one of two things; improving your distance, or speed-time. Beginners will undoubtedly be drawn to the allure of going further distances, but seasoned athletes are not enthralled by the same.
A point is reached when distance becomes enough. At that point improving your distance covered per time becomes the best training methodology.
For this, Yasso 800’s[ix] really shine. The way Yasso 800’s work is by you setting your desired goal time (usually in hours: minutes format) and running that same number in minutes: seconds over the course of 800 meters.
This is followed up by a light jog for the same amount of time before repeating the run at race speed. Eventually, you can repeat Yasso’s multiple times to achieve your desired workout duration.
The mantra “use it or lose it” is very real when it comes to endurance and fitness as a whole. The exact amount of time it takes for you to lose all that hard-earned endurance depends on several factors but can begin in as little as following 3-4 weeks of inactivity[x].
In part, it depends on your fitness level and conditioning when you stop. If you were a dedicated athlete with excellent muscular and cardiovascular endurance, you may notice very little loss at the three-month mark.
For others who may have been training for just a few short weeks and then stop, in a matter of just a few weeks, any gains made will be sacrificed.
In terms of your 5K time, expect to lose minutes after just 3 weeks of inactivity. Mitochondrial density declines significantly faster, with as much as 50% being lost in just one week.
Detraining, which is the correct term for the loss that occurs during this period of inactivity, is a useful tool in periodization training programs that serves as a means to continuously improve yourself with. This technique applies to both muscular and cardiovascular endurance.
The loss that is experienced is your body trying to get back to its state of homeostasis; it does not willingly hold on to adaptations that are not essential for your survival. This means also that VO2 max returns to baseline, as well as any accrued muscular endurance and growth.
A good way to avoid excessive detraining, or loss of all the endurance you worked so hard to earn? Go into “maintenance” mode. This means having at least one workout per week, done at least 70% VO2 max level.
Without a doubt, well-timed use of supplements can help take your game to the next level. Supplements can help buffer fatigue, improve energy levels and even enhance muscular function and contraction. Consider giving these a try.
The world’s favorite stimulant, caffeine is one of the few supplements that have a proven track record when it comes to endurance training[xi]. It acts as a bronchodilator (improving airflow and breathing) to support efficient oxygenation within the lungs. It may also help reduce fatigue and increase fat utilization for fuel.
For best results, take 200-400mg about 30 minutes before activity.
The supplement which serves to raise levels of intracellular carnosine, Beta-alanine helps delay fatigue and support high-intensity sessions. Carnosine acts as a sort of pH “sponge” buffer[xii], neutralizing H+ ions generated as metabolic byproducts of muscle contraction.
This effect takes time to manifest, so daily use is advised at a dose of 3.2-6.4g.
Well-timed carbohydrate consumption is an essential component of an endurance athlete’s arsenal. Carbs comprise 45-65% of calories daily and should consist of primarily slow-digesting sources on most training days. Faster sources such as maltodextrin and glucose are preferred intra and post-race sessions and workouts for a readily available source of energy.
Depending on if you are actively training for a race, or in regular off-season training, your carbohydrate requirements can range between 3-12g per kilogram of body weight daily.
Beetroot powder is one of those things that nobody takes seriously until they’ve tried it. In addition to supporting better blood flow, it can improve running velocity by an average of 3%. While this may seem insignificant, this is usually enough to mean the difference between first and tenth place in a race.
It can help shave seconds off your best[xiii]. 300-500g per day is the usual recommendation for beetroot powder supplementation.
A pseudo-amino acid which can improve endurance performance slightly, and also more noteworthy, reduce muscle breakdown and lactic acid levels[xiv]. This is significant as the muscle damage following a marathon can continue for weeks and increase predisposition to injury[xv].
The benefit on endurance performance can be single in as little as after a single dose ranging from 1-6g in size[xvi].
Choline taken in supplemental form helps to support muscle contractions and decrease fatigue[xvii], which in turn can lead to favorable race times and subsequently, recovery. As many as 90% of all adults are deficient in choline.
The usual recommended dosage of choline is 1-2g taken at the pre-workout interval.
Improving your endurance is an attainable goal that will reward you with better overall health and sense of well-being. It is also very important for you to remain consistent with your workouts, as it can be lost much faster than it is gained.
By following some of our recommendations mentioned above, you too can improve on your race times and distance, regardless of your discipline.
Matt Mosman (MS, CISSN, CSCS) is a research scientist, endurance athlete, and the founder and Chief Endurance Officer at EndurElite. Matt holds his B.S. in Exercise Science from Creighton University and his M.S. in Exercise Physiology from the University of California. Matt and his family reside in Spearfish South Dakota where they enjoy running, mountain biking, camping, and all the outdoor adventures Spearfish has to offer.