Are Swimmers Good Runners? (Here’s What the Research Says)


Swimming and running are two of the best aerobic exercises for people to get in shape. However, many people question whether success in swimming translates over to running.

Swimmers are more inclined to be talented runners because of their:

  • improved cardiovascular health
  • increased lung and oxygen capacity
  • relatively low body fat percentage
  • strong lower leg muscles
  • superior mental fortitude

This may not hold true for all swimmers though, as some individuals aren’t accustomed to the joint strength demands and injury risks associated with running.

Each of these variables will be discussed at great length in the sections below, so that you can have a thorough understanding of why swimmers have a leg up over the average person with respect to running.

Ways That Swimmers are Better Equipped for Running

Improved Cardiovascular Health

First and foremost, experienced swimmers have superior cardiovascular health, since the function of their heart, lungs, and circulatory system is tested every single time they hit the waters. Since all three of these anatomical areas are in such good health, their body is extremely capable of tackling the aerobic demands of running.

Through swimming, the heart pumps more blood with every beat, the lungs take in more oxygen with every breath, and the muscles get more efficient at using what oxygen is made available to them (source). Few other aerobic exercises push the body to such extremes in the manner that swimming does.

These cardiovascular benefits apply to all areas of fitness, not just swimming. These benefits help with running, for example, by improving muscular endurance and allowing individuals to run further than they would have if they didn’t train otherwise. It is for this reason that swimmers are typically able to run more miles than the average person, even if they do not run long distances on a regular basis.

Although the stimuli of swimming and running differ slightly from one another, cardiovascular health is essential to both modes of training.

Increased Lung & Oxygen Capacity

Furthermore, swimmers have a comprehensive understanding of how to fill their lungs with the most oxygen possible to supply their body with energy. Not only that, but there’s evidence to suggest that the total lung capacity of swimmers are slightly larger than normal.

The human body is smart in that it adapts to whatever repetitive stimuli with which it is presented. A prime example of this can be seen in the lung capacity of swimmers. Spending long hours underwater ultimately forces the lungs to optimize its oxygen uptake, as the body grows accustomed to training under circumstances where there’s no oxygen readily available.

As of late, there have been research studies performed on this very topic. For example, a recent study analyzed the respiratory system of elite male swimmers versus elite male football players. The results corroborated the notions that swimmers do in fact have superior lung capacities (source).

Swimmers had an average vital capacity of 6.2 L, whereas football players had an average vital capacity of 5.4. As a quick reference, vital capacity describes how much air has been expelled from the lungs following a maximum inhalation.

Although these results are promising, the researchers do state that there’s still further work to be done before any definitive conclusions can be drawn about this subject.

Regardless, these benefits of oxygen uptake are extremely worthwhile to have when running. The more oxygen that a runner can take in, the more energy they’ll have to notch more miles under their belt. This is a major reason why swimmers find so much natural success when they shift over to running.

Relatively Low Body Fat Percentage

In addition, swimmers generally have a reduced body fat percentage. This is because swimming is a tremendous calorie burner. It’s universally considered one of the most effective strategies for shedding excess body fat and losing weight.

The primary reason that swimming is so good at lowering body fat percentage is that it helps people to establish a caloric deficit. For those of you that do not know, a caloric deficit describes a dietary situation where an individual consumes less calories than their body utilizes within a set time interval. Consequently, the body resorts to depleting fat stores for energy. If the caloric deficit becomes too severe, the body may even resort to breaking down muscle for energy.

There are two main ways to establish and maintain a caloric deficit:

  1. Reduce Caloric Intake via Food and Drink – Less calories are made available to the body for potential energy usage, so the body must explore other options for energy creation (i.e. fat stores).
  2. Increase Physical Activity Levels – The body requires more energy as physical demands go up, so current caloric intake will not be enough to fuel the body. As a result, fat stores are burned for energy.

In most cases, swimming will help to set a moderate caloric deficit since physical activity is increased, resulting in long term weight loss.

A reduced body fat percentage is favorable for runners because there’s less weight to slow them down, allowing them to move at a slightly faster pace. Moreover, there’s less weight bearing down on the knee and ankle joints, which helps considerably with injury prevention.

Strong Lower Leg Muscles

Furthermore, swimming on a regular basis strengthens the lower body substantially.

No matter what swimming stroke you perform, the legs are always involved. Think about it. The freestyle, butterfly, backstroke, and breaststroke all rely on the legs as another source of propulsion. The arms cannot do it all. Even the simple act of treading water relies heavily on the legs to keep an individual afloat.

With swimming, the leg muscles are challenged to the utmost. They’re in a state of perennial activation, moving back and forth to keep the body gliding through the water. Very rarely do the leg muscles ever receive an extended break. As a result, the muscular stamina of these leg muscles gradually builds to fit the needs of running. It should be noted that there are few other modes of training that replicate the constant stress of running.

These perpetual kicking motions linked with swimming also reinforce the muscles around the joints, which wards off injury. This added muscular strength also has a noticeable effect on driving power, helping runners to get more out of every stride.

For all these reasons, it’s no wonder that long distance runners occasionally cross-train with swimming. They still receive all the muscular benefits of running with swimming, but they get to forgo the knee and ankle problems that generally result from repetitive weight overload. Since swimming greatly reduces pressure on the joints, such injuries are not a common issue for frequent swimmers.

Superior Mental Fortitude

Lastly, swimmers have the mental toughness that’s essential for running long distances.

Not everyone has the mental fortitude to force themselves forward when their body is screaming for them to stop. This is the constant internal battle that a runner faces as they near the end of their workout. Runners rely heavily on their own self-discipline to make progress and go a little bit further than they did the day prior.

Not many people can relate to this struggle, unless of course you’re a swimmer. Swimmers face this same internal battle of whether they should continue to move forward… or just stop.

Experienced swimmers know how to conquer such temptations and continually improve day after day. This mentality may not be at the forefront of everyone’s minds when determining if swimmers are naturally good runners, but it’s an important fact to consider nonetheless.

This variable is difficult to quantify, but it’s certainly a major reason behind why swimmers tend to have a natural affinity for running.

Common Struggles that Swimmers Encounter with Running

Even though swimmers are prepared in a number of ways to become an accomplished runner, there are a few aspects of swimming that actually detracts from running. If these drawbacks are serious, they may even have the capacity to hold back a swimmer from showcasing their true running potential.

Insufficient Bone Density

For one, swimmers do not have to deal with the absorbing shock of land-based sports. Although this does yield benefits in injury prevention, it detracts from other fitness areas, namely bone density.

It is essential for runners to have a dense bone structure to endure the repetitive stress of running. The weight-bearing bones of the legs, pelvis and spine must have superior strength to serve as a solid foundation for every single running stride. If there’s any weakness found in this bone tissue—like a below average bone density for example—there’s a much higher likelihood that a stress fracture may arise in the near future (source).

Unfortunately, swimming does very little to improve bone density due to water buoyancy. This buoyancy allows individuals to float in the water during their workout, which minimizes any stress placed directly on the bones. Thus, swimmers aren’t not afforded as much of an opportunity to apply positive stress on their skeletal system, resulting in a minimal boost in bone density.

For this reason, swimmers may not have the exceptional bone density needed to break through the initial barriers of long distance running. Instead, they may encounter problems with shin splints or stress fractures, as their bodies are still adjusting to the constant weight-bearing load of running.

Put simply, if a swimmer does not enhance their bone density through alternative means, their body may not be up to the task of running.

Adjustments to Breathing Technique

Furthermore, swimmers may also have a hard time modifying their breathing to fit the demands of running over swimming. Even though swimming and running are both cardiovascular exercises, the rate at which these athletes take in oxygen slightly differs.

Swimmers are conditioned to take in breaths only when absolutely necessary, since resurfacing for air hinders their ability to move forward as quickly as possible. It interrupts their rhythm and could even halt whatever momentum they’ve generated over the course of the past few strokes.

For this reason, swimmers take special care to time their breaths so that they’re sufficiently spaced out. Even when they do decide to take in a breath, they do so quickly to avoid wasting any time that could be spent executing their next stroke.

This breathing pattern is vastly different from how runners are taught to breathe. Since runners do not ever have to deal with being underwater, they have a constant supply of oxygen readily available to them. They can inhale deeply down into the bowels of their diaphragm to deliver as much oxygen to their body as they need. Thus, runners are constantly inhaling and exhaling, with no need to hold their breath.

Some swimmers may have trouble readjusting to this high tempo breathing pattern after having conditioned their lungs to space out each breath. A few swimmers may not ever make this adjustment, which will inevitably hold them back from ever becoming a great runner.

Are Runners Good Swimmers?

Now that you know that swimmers have an assortment of tools at their disposal to develop into a natural runner, you’re likely wondering if it works the other way around.

The short answer is that runners do not necessarily make for good swimmers. The reason being that much of becoming a good swimmer has to do with refinement of technique more than anything else. The learning curve for swimming is a lot steeper than the learning curve for running.

A runner may have all of the cardiovascular prowess required of a good swimmer, but this matters little if they do not know how to correctly move in the water with proper fundamentals. Plus, a lack of swimming knowledge often leads to panic and disarray in the water, which causes entirely different set of problems. It’s hard to swim quickly when you’re sole goal is to fight to keep your head above water.

This is not to say that running doesn’t help with swimming. It certainly does, with the exception that the individual knows how to swim. After all, both swimming and running are aerobic exercises, so they improve similar areas of health.

The Bottom Line

Experienced swimmers will often have an easier time running than the average person, due to their superior cardiovascular health, increased lung capacity, low levels of body fat, strong lower body, and relentless mental attitude.

These benefits transition over well into long distance running. This crossover between swimming and running goes to show just how much of a positive impact that swimming can have on someone’s health. So if you haven’t done so already, go out and hit the pool!

Sources: 1 2 3

Austin Carmody

I am the owner of HydroPursuit. I enjoy kicking back and getting out on the water as much as I can in my free time.

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