How to Improve Endurance for a Healthier Heart and Stronger Muscles

When you find yourself lacking the energy to power through daily tasks, or even trying out a new hour-long workout class, you may initially attribute it to a poor night of sleep or ordinary stress. While those factors are indeed contributors to your energy drain, it’s worth considering another aspect: Your physical endurance.

What Exactly Is Endurance?

Physical endurance simply refers to one's ability to sustain a certain level of activity for an extended period. This term is often associated with athletes, particularly those involved in sports requiring them to endure long, taxing physical efforts over time (think: marathon runners, professional soccer players, cross-country skiers). However, elite athletes aren't the only ones who benefit from—or need—physical endurance. Whether you're walking your dog for hours or spending a whole day at an amusement park with your kids, every body requires a degree of endurance to get through life. And it’s something you can continuously improve and develop.

There are two primary types of physical endurance: cardiovascular endurance and muscular endurance.

Cardiovascular Endurance

“Cardiovascular endurance refers to your body’s ability to exercise for prolonged periods, such as running a 5K or taking a cycling class,” says Jen Rulon, fitness coach and 15-time Ironman triathlete. This form of endurance is what helps sustain activity when your heart and lungs work together to supply your body with the oxygen needed to keep moving.

“Cardiovascular endurance is vital for both your daily functioning and your performance in sports and physical activities,” says Alex Rothstein, MS, CSCS, coordinator and instructor for the exercise science program at New York Institute of Technology in Long Island.

How can you build endurance? As you might expect, movement—specifically aerobic activity—plays a crucial role for many reasons. The more endurance you develop, the better you’ll be at performing activities at higher intensities and for longer periods of time,” explains Rothstein. If you’ve ever experienced fatigue during an activity or even had to stop because of a burning sensation, improving your cardiovascular endurance can reduce these occurrences.

Improving your cardiovascular endurance can lead to notable enhancements in your overall health. Enhanced endurance can help lower your cholesterol and blood pressure, says Rulon, and it also strengthens your respiratory and circulatory systems.

Endurance vs. Stamina

However, it’s important to note that endurance is often confused with stamina. While they are related and share similarities, cardiovascular endurance focuses solely on the physical aspects of sustaining physical exertion, while stamina also incorporates psychological components. “Stamina is a mix of cardiovascular endurance and the ability to handle fatigue,” says Rothstein, adding that it also involves the mental fortitude to push through the sensation of tiredness.

Muscular Endurance

Cardiovascular endurance mainly involves the heart, while muscular endurance focuses on the strength and stamina of your muscles. “It’s about how many times you can lift a weight without getting fatigued, which is essential for improving your cardiovascular system,” explains Rulon.

Muscular endurance is closely linked to muscular strength, which is the maximum force your muscles can generate in a single effort. By enhancing both muscular strength and endurance, “you’ll improve your ability to manage stress and tackle cardiovascular training,” says Rothstein.

How to Build Endurance

If you're looking to build these two types of physical endurance, it's time to get moving. Developing cardiovascular endurance requires engaging in aerobic activities (such as walking, jogging, swimming, or cycling). However, how you perform these activities matters, which is where the concept of 'specific adaptation to imposed demands' (SAID) comes in. The SAID principle suggests that the body will adjust to the specific challenges it faces. “To improve cardiovascular endurance, your cardiovascular system must be stressed enough to trigger the need for adaptation,” says Rothstein.

To achieve this, there are three key variables you can manipulate:

• Frequency (how often you exercise)
• Intensity (how vigorously you exercise)
• Duration (how long you exercise)

“Adjusting any one or a combination of these variables will challenge your cardiovascular system in different ways and result in different adaptations,” says Rothstein. For example, increasing the duration of your workouts will signal your body to enhance its ability to burn fat for energy, allowing you to exercise for longer periods, while higher-intensity workouts may boost your body’s ability to deliver more oxygen and utilize it more rapidly and efficiently.

Similarly, to improve muscular endurance, you need to engage in strength training, focusing on higher repetitions with lighter weights, according to Rulon. Aim for two to three full-body strength training sessions per week, as recommended by the American College of Sports Medicine.

How Long Does It Take to Build Endurance?

How long does it take to improve your physical endurance? The timeline varies for each individual, but generally, Rulon says that if you're doing three 30-minute workouts per week, you'll start seeing improvements in cardiovascular endurance within 8 to 12 weeks. For muscular endurance, many studies show that improvements can be observed after six weeks.

Continuously Challenge Yourself to Build Endurance

Whether you're working on building cardiovascular or muscular endurance—or both—it's crucial to challenge your body and trigger the need for adaptation (meaning getting stronger and being able to handle that weight and/or activity for longer periods!). Once you’ve adapted, and the activity becomes easier or progress stalls, it’s time to adjust. Perhaps you start running 10 minutes longer, increase your sprinting intensity, or run more frequently throughout the week. Without these adjustments, it’s easy to hit a plateau, says Rothstein.

The Importance of Recovery and Rest

The key is finding a balance: Don’t push your training too hard, as that could lead to injury, warns Rothstein. Recovery begins the moment your workout ends, and that recovery time is essential for building endurance. “Exercise that promotes the need for adaptation will temporarily weaken you,” he explains. “During rest and recovery, you rebuild and come back stronger.”

However, many people, driven by excitement to progress in their fitness journey, skip cool-down routines and necessary rest days—and that’s a mistake. Make sure to take at least one day off from structured exercise each week, or more if you’re new to exercise or doing extremely high-intensity workouts.

Recovery also involves ensuring you get adequate sleep. “Sleep enables your body to recover and rejuvenate,” says Rulon. Interestingly, sleep and exercise are interrelated, as quality sleep has been shown to enhance exercise performance, while exercise can potentially improve sleep quality, adds Rothstein. For adults, the recommended amount of sleep is seven to nine hours each night.