Why Open Water Swimming Requires More Endurance Than Pool Swimming
Many athletes are surprised when they get into open water and discover that swimming 1 mile in a lake feels very different than swimming 1 mile in a pool. The reason is simple: open water is continuous.
In the pool, every lap gives you a small break. Even if it’s only a fraction of a second, each wall allows you to streamline, glide, change muscle recruitment, reset your rhythm, and momentarily reduce the workload. Over hundreds of turns, those little breaks add up. In open water, there are no walls. You simply keep swimming.
That means the endurance and strength demands are significantly higher, especially as the distance increases.
Conditions Add Fatigue
Open water is rarely calm and predictable.
You may encounter:
Chop
Waves
Wind
Currents
Other swimmers
Limited visibility
Cold water
Wetsuits
Every one of these factors increases energy expenditure. A small chop can disrupt your breathing pattern. A current can force you to work harder without realizing it. Swimming in a crowded start may require constant adjustments to your stroke and body position. The stronger and more durable your swim fitness is, the less these conditions affect your performance.
Why We Do So Much Pulling
Athletes often wonder why open water swim programs include so much pulling compared to traditional pool swimming.
The answer is strength endurance.
A wetsuit lifts the legs and changes body position, allowing the arms and upper body to become the primary source of propulsion.
To swim efficiently in open water, you need:
Strong lats
Strong shoulders
Strong upper back muscles
The ability to maintain good mechanics under fatigue
Pull buoy and paddle work help develop the specific strength required to hold form for long periods of uninterrupted swimming.
This isn’t about becoming a stronger pool swimmer. It’s about becoming a stronger open water swimmer.
Confidence Comes From Over-Distance Training
One of the biggest reasons we occasionally prescribe swims that are longer than race distance is confidence.
Could you complete your race with only shorter swims?
Probably.
But confidence isn’t built by hoping.
Confidence is built through experience.
When you’ve completed swims that are longer than your goal distance, you arrive at race day knowing you have the fitness to handle whatever conditions show up.
If the water is rough…
If there’s a strong current…
If the swim takes longer than expected…
You know you’ve already done more.
That confidence is incredibly valuable when anxiety starts creeping in before the start.
Race Distance Isn’t Always Race Effort
A two-mile swim in a pool and a two-mile swim in open water are not always equivalent.
In open water you must continuously:
Navigate
Sight
Adjust to conditions
Manage effort
Stay calm
Maintain rhythm
All while moving forward without interruption. The physiological and mental demands are simply greater.
That’s why athletes preparing for open water events, triathlons, marathon swims, and Ironman races need a larger endurance foundation than they might initially expect.
The Forgotten Skill: Swim Exits and Re-Entries
Many open water races include multiple laps with a short run between laps. This creates another challenge. When you stand up and start running, heart rate often spikes dramatically. Athletes who are not prepared for this frequently panic when they dive back into the water and suddenly feel breathless.
A better approach is to:
Stand up gradually
Walk or jog smoothly
Control your breathing
Lower your heart rate
Re-enter the water calmly
Experienced athletes make these transitions look effortless because they’ve practiced them. Like all skills in endurance sports, it gets easier with repetition.
The Goal Is Simple
The goal of open water training isn’t just to swim the distance. It’s to build the endurance, strength, durability, and confidence to handle the distance regardless of the conditions.
When race day arrives, you want to be standing on the shoreline knowing:
“I’ve done the work. I’ve swum farther than this. I’ve handled tougher days than this. Whatever the water gives me today, I can handle it.”
That confidence is one of the greatest advantages an athlete can carry into open water.