How Long Runs Build Physical Fitness, Mental Toughness

Two people running in Mizuno shoes

Ask any runner or coach what the most critical component of a marathon training plan is, and the unanimous answer will be the long run. That’s because the long run’s physiological benefits are indisputable.

First of all, it strengthens the heart: Ventilatory capacity—the ability to move oxygen in and out of our lungs—increases. The musculoskeletal system adapts and grows stronger thanks to long runs. Endurance improves because mitochondria (the energy-producing structures in cells) and capillaries (tiny blood vessels that transfer oxygen and waste products into and out of cells) become more dense the farther you go. You also get better at using fat, rather than glycogen, as a fuel source. The list goes on.

Without a doubt, your hardware vastly improves with each of these physiological benefits, but the often understated—and potentially more impactful—advantages of the long run come from the software improvements.

Let’s face it, racing your best at any distance requires an immense mental effort. Going long calluses you mentally and gives you confidence in your ability to cover the miles at a grueling pace come race day.

A woman running on a bridge in the Grand Canyon

Physical or mental?

In the athletic world, much of training is focused on hitting specific workouts and developing the muscles and body to achieve athletic goals.

After a stellar race performance, your instinct is to attribute that success to specific physical achievements from training. Was it the one big workout you crushed? Or maybe it was the high weekly mileage you sustained throughout the training cycle? While the physical training (hardware) is certainly necessary, the mental training for running—your software—is often neglected.

Think back to a race in which you excelled. What were you were thinking about during the race? You likely weren’t thinking about how terrible you felt and telling yourself you couldn’t do it. Instead, you remember how great you were feeling, or maybe you don’t remember much of the race at all because you were in the zone.

On the other hand, the opposite is likely true of how you were feeling mentally during a poor performance. Each step was accompanied by a negative thought questioning whether you could even make it to the finish.

The interesting distinction between the great race and the poor race is that you may not have been in better shape physically for either one. In fact, you could have been in better physical shape for the poor race. The difference was simply your mindset. But how does your mind make such a big difference?

What truly matters? Perception of effort

Performance is linked to perception of effort. Even if you are running the exact same pace on multiple occasions, the perceived efforts of those runs will vary.

Some days the pace feels harder than others. Thus, your goal in training should not just be to hit specific splits in workouts but rather to practice being comfortable mentally even when your body is uncomfortable physically. The concept is described perfectly and with much greater detail in the book "Peak Performance" by Brad Stulberg and Steve Magness.

The best way to minimize perceived effort while maintaining maximum performance is by achieving flow. In a flow state, a person performing an activity is fully immersed in a feeling of energized focus. This is often described as being in the zone.

Everyone achieves flow from time to time, but the goal is to be able to enter the state at will. By giving mental training your full attention during each workout, and especially during long runs when physical and mental fatigue are inevitable, you can develop tools to help you more easily achieve flow.

Overriding your brain’s circuitry

Our ancestors were concerned with survival, not competing, which is why we are programmed to back off when we become excessively fatigued or in pain during a race.

Our brain acts as a central governor with a safety circuit to protect us from any long-term harm. However, we can extend the boundary of our circuitry over time and override the switch in the short-term to achieve a breakthrough race.

The notion is repeatedly illustrated by racers who say they are “completely dead” and unable to go faster during the late stages of a race but are able to override their circuitry to muster a finishing kick when the finish line is in sight.

By understanding how the brain works and why we are receiving certain signals throughout a run or race, you can develop the ability to quash your instincts.

Adapting to resist mental fatigue as much as physical fatigue is crucial. Nearly everyone has similar pain thresholds, but upping pain tolerance is the key to achieving the next level, as described in the book "Endure" by Alex Hutchinson. Learning to have an appetite for suffering may not sound like fun, but by simply incorporating awareness of your mental state into your existing training regimen, incremental progress will quickly ensue.

Two birds, one run

Brain training and physiological training do not need to happen in silos. Many of the software improvements come simultaneously with hardware improvements.

When you are physically training, you are concurrently increasing your pain tolerance and familiarity with fatigue and pain. As a result, you become mentally more robust as your brain becomes familiar with the suffering required at a given effort level.

The mental toughness will come naturally on race day if you put yourself in positions during training that are as bad or worse than how you will feel during the race. Learning to cope and accept the pain and suffering as a normal feeling during peak performance requires you to be cognizant of your mental state during each step of training.

It is important to use each run as an opportunity to improve mentally, as well as progressing physically. This is especially true during long runs and on hard workout days where the effort is high and an optimal mental state is needed to successfully complete the prescribed paces/distance.

Being intentional and planning ahead for how you will mentally approach long runs and hard days will help you get the most of training.

Here are some tips to keep in mind as you commence a long run or workout:

1. Remember your purpose

During a warmup, remind yourself of the purpose of both the individual workout and the larger picture. Is there a goal for which you are training? Is there a meaningful purpose behind why you run? It is much easier to tolerate discomfort when you know that doing so is tied to a meaningful purpose or long-term goal. Once you understand the why, it's easier to navigate the how.

2. Find a way, not an excuse

It’s easy to talk yourself out of upcoming hard workouts before even starting them. You are too tired. You are sore. It might rain. It is too hot/cold/windy. The first step in overcoming this pitfall is to recognize when it is happening, and instead of quitting, reassure yourself that you will be fine. Just focus on giving your best effort on that day, and avoid putting excessive pressure on yourself about things that are out of your control.

3. Employ positive self-talk

Use the power of self-talk to engage willingness and optimism throughout the run. When the going gets tough, repeat positive statements in your mind to help you push through. “I am” and “you are” statements are both great ways to start. For example, you can use phrases like “I am capable of this effort,” “I am getting faster with each step,” and “you are killing it.” You can also repeat statements, like “stay relaxed.”

4. Adapt to any conditions

Mental toughness not only arises during hard training sessions, but also by overcoming adversity thrown your way. If the weather is miserable, embrace it. Used to running at a specific time of day? Try running at a different time once in a while to practice switching your routine. Learning how your mind reacts to unpleasant experiences will help you formulate methods for tolerating and overcoming them.

5. Stick with it!

The moment your body crosses the threshold into an area of discomfort, your thoughts will seek a place of refuge. Negative thoughts will undoubtedly arise the longer and harder you run. In such moments, it is pivotal to enact self-discipline and train your mind to tolerate the experience instead of backing down and taking your foot off the gas. Developing this ability during your long runs and in practice each day will allow you to access this same skill set come race day when it matters most.


By Chris Robertson. Robertson races competitively for Chicago’s Fleet Feet Nike Racing Team. He holds a marathon personal best of 2:24 and is the Beer Mile American Record holder (4:46). He is currently training with the goal of qualifying for the 2020 Olympic Trials Marathon and defending his 2017 Beer Mile World Title while working full-time as a Technology Consultant and pursuing additional entrepreneurial endeavors.

Join our Newsletter

Get deals, events, and more.

Connect with Fleet Feet

Get involved on social media.

Find a Location

Fleet Feet has over 175 locations nationwide!

Find a Store