Exercise Intolerance Has Nothing To Do With Your Fitness or Motivation To Work Out. How Do You Know if You Have It?

We’re always told that exercise is a good thing, but as with most things said in absolute terms, there are instances in which exercising could actually be harmful. One such scenario is when someone suffers from exercise intolerance. It’s something many people have never heard of, but it can affect people suffering from a variety of conditions.
What is exercise intolerance?
Hallie Zwibel, DO, director of the Center for Sports Medicine at the New York Institute of Technology, explains that exercise intolerance is the inability to engage in physical activity that would be typical for an individual’s age.
“Individuals with exercise intolerance cannot build the necessary stamina with exercise,” explains Dr. Zwibel. “In fact, exercising can cause more discomfort.”
Make no mistake: Exercise intolerance is different from just being out of shape or unmotivated to work out. This is an actual condition that can affect your physiology. When someone has exercise intolerance, their body doesn’t respond to working out by growing stronger—instead, physical activity can make someone feel worse. Dr. Zwibel says this happens because there’s less oxygen-rich blood being circulated throughout the body.
“A person can be motivated to work out, but their body cannot meet the moment,” he says.
What are the symptoms?
The reason that some people confuse this condition with a lack of fitness is because the symptoms can mimic those of someone who is “out of shape.” Namely, people will feel winded and fatigued when they’re starting exercise. Many also experience muscle cramping and aches. These responses make it difficult for them to sustain exercise in a comfortable or manageable way.
What are the most common causes?
There are various underlying causes of this condition. Dr. Zwibel says that two common ones are heart failure and chronic obstructive pulmonary disease (COPD). It can also be a symptom associated with chronic fatigue syndrome or POTS. Yet some of the causes may not even be identified or fully understood at this point
“There has been research linking long COVID-19 to exercise intolerance as well—even after symptoms resolve from acute COVID-19,” shares Dr. Zwibel. “The mechanism for this remains unclear but may be related to lung or cardiac issues.”
In addition to the lingering consequences of COVID, Dr. Zwibel says that a host of other respiratory conditions, like asthma and COPD can also cause it.
“Oxygen-rich blood is needed throughout the body to maintain all bodily functions. Respiratory conditions can negatively impact the blood being oxygenated,” he says. Meanwhile, certain cardiac conditions can mean that the oxygenated blood does not reach the tissues where it is needed.
The good news: Fortunately, not everyone with these types of conditions will necessarily suffer from exercise intolerance. Whether you’re affected often depends on the type and severity of your health problem, your fitness level prior to becoming sick, and how well your condition is being managed.
Can you still work out with exercise intolerance?
It may sound like people who have exercise intolerance should avoid working out at all costs, but Dr. Zwibel says this is an unnecessary precaution—and also counterproductive in most cases.
“You can and should exercise, with one big caveat: Exercise programs need to be tailored to the reason a person has exercise intolerance,” he says. “There’s not a one-size-fits-all approach. That’s why it is critical to seek advice from a qualified healthcare professional.”
A provider should closely monitor how your body responds to activity, and offer targeted levels of physical exertion for you to follow, says Dr. Zwibel. “This has been shown to improve exercise intolerance—and help to improve quality of life.”