Endurance is your ability to keep on keeping on – keep on trucking.
Many athletes and fitness professionals think of it in terms of exercise and performance.
I emphasize endurance as the ability to keep on breathing, hopefully until you’re well past 100 years.
To me, that’s the real point of endurance. I stopped racing decades ago. Who cares who wins or loses? But developing the physical capacity to exercise for long periods contributes to your ability to continue breathing until you’re a supercentenarian.
That’s even better than an Olympic gold medal.
Also, physical endurance enables long-term mental performance as well.
The more efficiently your body uses energy, the more effectively it maintains itself – and the better you feel both physically and mentally.
And likely, the longer you’ll live.
The Body’s Energy Sources
To do anything, your body requires energy – and that means using ATP.
The mitochondria in your cells produce ATP through taking oxygen and glucose (or fatty acids) from your blood and combining or burning them.
First off, for fast energy, the mitochondria in your muscles cells turn to phosphocreatine. That’s effective for short bursts of effort, and so is not part of endurance.
When that’s depleted, your body turns to glucose. That’s basically sugar, from the carbohydrates you eat.
When you use up all the available glucose, your body digs deeper for energy, burning glycogen from your liver.
Then your body releases fatty acids from your stored fat.
And, of course, throughout all of this, you need oxygen.
One Major Component of Your Endurance
Neurons in your brain, neurons linked to your muscles.
When they’re well supplied, you feel the motivation to keep going, and can keep moving your muscles.
What do they need? Energy – primarily from glucose, though they can also use fatty acids such as ketones.
They also need electrolytes: sodium, calcium, magnesium and potassium.
Other Vital Organs
Your muscles depend on oxygen and glucose from the blood, so your heart and your circulatory system as a whole limits your endurance.
So do your lungs, and their capacity to take in oxygen.
Nearly 60 years ago, one of my swim team coaches told us we needed strong hearts and lungs, and science still confirms that.
The Kinds of Endurance Training
(Note: the suggested workouts are based on scientific studies. Of course, you have to start with where you are right now – and then slowly work your way up.)
1. Muscular endurance
This is the ability of your muscles to keep on working . . . until they no longer can, because of the muscle tissue.
If you work out specifically to improve muscular endurance, look at performing three to five sets of between 12 to 100 repetitions.
Those sets are done with between 30 seconds and 3 minutes of rest in between. That will vary by how much muscular endurance you have right now. Start small and build up.
Planks and pushups are both good. So are squats to work your leg muscles.
2. Long Duration Endurance
This is what we usually think of as endurance. It’s anywhere from 12 minutes on up. Running, walking, swimming, biking or whatever.
This type of endurance is developed by going out and performing the activity for 12+ minutes. In terms of a “set,” it’s one set.
Use pioneering track coach Dr. Phil Maffetone’s MAF 180 Formula to determine your sweet spot for increasing this type of endurance.
Subtract your age from 180. Subtract 10 if you’re just starting out or out of shape. Add 5 if you’re already well-trained. If you’re 65+, just use 115.
Use a heart rate monitor to keep your heart rate at that number as you run.
If you’re 40 and out of shape: 180 – 40 = 140 – 10 = 130. Keep your heart rate at 130.
Run just hard enough to keep your heart beating at the MAF. If it goes over that, walk until your heart slows down.
The MAF is high enough to work your body, but not so high you can only do it for a short period.
It’s between a light jog and an all-out sprint.
Go for as long as you can.
Gradually, your distance will increase even though your effort (as measured by your heartrate) remains the same.
How Long Duration Endurance Enhances Your Life
As you do long duration exercise, your cells respond by creating new mitochondria. Your muscle cells become more mitochondrially dense, enabling them to use more ATP at any given moment.
This long duration effort does something else extremely important: it builds capillaries in your muscles.
Those are the tiny blood vessels that actually supply your cells with oxygen and nutrition – including the glucose and fatty acids the mitochondria need to create ATP.
Your arteries carry blood, with its oxygen and glucose, to all parts of your body. Your veins return blood to the heart.
In between, tiny microcapillaries connect arteries and veins – and it’s from these small blood vessels that your cells get what they need.
Long duration exercise builds more of these microcapillaries. The more microcapillaries in your muscles, the more blood is available to them. The more blood, the more oxygen your muscles have access to. The more oxygen, the longer your muscles can keep going.
In response to this long duration effort, your body also builds more microcapillaries around your heart, giving it a greater capacity to survive a heart attack.
3. High Intensity Anerobic Training
Many fitness experts in the past few decades have promoted the concept of HIIT: High Intensity Interval Training.
In many ways, it’s not new. In the late 60’s, my most educated swim coach – fresh from a college competitive team – introduced us to interval training.
It was a brutal experience.
We’d use a big pace clock on the deck to tell us to start swimming a certain interval. We had a certain period to do it in. After finishing, we could rest until time to go again.
Then we’d repeat . . . and repeat . . . and you get the idea.
If you’re running, so you can track your time, you can sprint for a defined, short period such as ten to thirty seconds.
Then rest for a defined period.
Based on the latest science, HIIT anerobic training consists of three to twelve sets. The ratio of sprint to rest is anywhere from three to one – to one to five.
Even one to five (sprinting ten seconds then resting for 50 seconds, for example) is more difficult than you might think, unless you’re already well-trained.
Adjust for where you are now, gradually increasing the number of sets and decreasing the resting time.