Overcome Your Endurance Limits | Endure, by Alex Hutchinson

26 July 2022[updated]

7 min read


"Endure: Mind, Body, and the Curiously Elastic Limits of Human Performance" is a non-fiction book, written by Alex Hutchinson, about what factors, both mental and physical, contribute to improving or limiting athletes' endurance.

He presents the results of many research projects in the field of running and endurance. He then describes how those results affect your limits and your maximum potential. Many of those projects aimed to learn how to overcome your endurance limits in order to reach new performance levels.

Some of those limits are purely physical: how much effort and strain your muscles are able to sustain, how much dehydration becomes detrimental, the effect of hot temperatures and overheating. But there are also other factors that are purely mental.

Those self-imposed mental limits may be holding you back more than you ever thought possible, and many research projects have been carried out to prove this idea.


The limits of endurance running

The book focuses mainly on the world of running. There exist many different types of running competitions and distances: from the most popular 100m sprint to ultra-marathons that can last days or weeks. The preparation required is different for every distance. However, some factors are common between all disciplines.

The author points to three main variables that define the endurance capabilities of each athlete: VO2Max, running economy, and lactate threshold. Those factors are the main enemies for every runner and athlete in general. They can also only be trained up to a certain limit that varies based on your genetics and many other circumstances, like altitude, motivation, equipment.


Your VO2max reflects your aerobic limits. At higher speeds, your legs demand energy at a rate that aerobic processes can’t match, so you have to draw on fast-burning anaerobic (“without oxygen”) energy sources.

Alex Hutchinson

VO2Max is defined as the maximum amount of oxygen you can utilize during exercise. When the intensity of the workout becomes too high for your aerobic processes to keep up (from Greek aero - "air" + bios "life"), you reached your VO2Max limit and enter an anaerobic state (from Greek an- "without"). Without oxygen, your body produces lactate which eventually will limit your maximum performance and endurance limit.

Running Economy

If you want running at 5:00-mile pace to feel easier, you should head out the door and run at 5:00-mile pace—a lot.

Alex Hutchinson

The Running Economy is the energy demand for a given velocity. The more straining a given pace is, the more energy is required to sustain it. This energy demand can be improved with training and it reduces once you become more accustomed to a higher pace. Nonetheless, certain athletes are more genetically suited to have lower levels of energy expenditure given a certain speed, and therefore they are better equipped to sustain long-running distances at faster paces.

Lactate Threshold

Your muscles’ ability to tolerate high levels of lactic acid—what we would now call anaerobic capacity—is the other key determinant of endurance.

Alex Hutchinson

The Lactate Threshold is defined as the maximal effort or intensity that an athlete can maintain for an extended period of time with little or no increase in lactate in the blood. A higher threshold means that you can sustain a greater intensity for longer times, which is of crucial importance in long-distance endurance competitions.

The limit of your mind

The limits we encounter during exercise aren’t a consequence of failing muscles; they’re imposed in advance by the brain to ensure that we never reach true failure.

Alex Hutchinson

One interesting and potentially revolutionary argument is that the mind is actively limiting our maximum potential effort in order to preserve a safety biological status. In other words, the reason you are not able to push beyond a certain point is not that you muscles cannot handle any further strain, but because your mind hinders any extra effort. You are always restraining yourself in order to save energy for possible future uses.

An example is a typical pace sustained during international running competitions: at the end of race athletes usually sprint as fast as they can to outrun their competitors. It seems like your mind is restraining you in order to be able to endure the long-distance ahead, but once you know that only a small distance is left before the end, you find a spark on energy to sustain a sprint. Therefore, your muscles are able to sustain the effort and they are not the cause of your limits in those situations.

Altering Your Sense Of Effort

If you could train the brain to become more accustomed to mental fatigue, then—just like the body—it would adapt and the task of staying on pace would feel easier.

Alex Hutchinson

Another interesting idea is training your mind to improve your physical limits. An important variable in any endurance endeavor is being able to mentally sustain a certain amount of effort for a long period of time. It is the ability to keep up your pace without being discouraged by the prospect of the long distance that you still need to cover.

Some research projects sustain that if you train your mind to be more accustomed to fatigue, for example by sustaining a high level of focus on one task for a long period of time, you can simultaneously improve your endurance limit.

Response Inhibition

The essence of pushing to your limits in endurance sports is learning to override that instinct so that you can hold your finger a little closer to the flame—and keep it there, not for seconds but for minutes or even hours.

Alex Hutchinson

How much pain an individual can sustain is different from person to person. Top endurance athletes must be able to inhibit and sustain higher levels of pain for longer periods of time. Some research points out that the level of pain you can handle can be trained, and that athletes have a higher response inhibition than no-athletes.

Embrace Pain

The end point of any performance is never an absolute fixed point but rather is when the sum of all negative factors such as fatigue and muscle pain are felt more strongly than the positive factors of motivation and will power.

Alex Hutchinson

We usually do not reach our physical limit. When you choose to stop is more often a conscious decision. It is the mind that dictates when to slow down. Every person has a different limit based on the amount of pain you can consciously sustain. Therefore, top athletes develop a higher resistance, they must be able to embrace pain and keep moving forward.


During easy exercise, like a gentle walk, you burn mostly fat from the supplies circulating in your bloodstream. As you speed up, you begin to add more carbohydrate to the mix, and by the time you’re panting heavily, the proportions have flipped and you’re burning mostly carbohydrate.

Alex Hutchinson

The amount and type of fuel are different for every distance. Not having enough energy for a short and intense sprint is a serious problem for short-distance races. On the other hand, if you must sustain a less intense pace for longer, you must be able to efficiently store and utilize your fuel for the long-term. All those considerations contribute to your diet choice.

Reaching a new level

You have to teach athletes, somewhere in their careers, that they can do more than they think they can.

Tim Noakes

After all those considerations, the secret at the end is always to give your best in every circumstance. There is no real substitute for hard work when it comes to physical improvement. In order to overcome your limits, you must reach them, get used to higher and higher levels, and being physically and mentally prepared.

Thanks for reading.