What is Exercise-Associated Collapse?
Exercise-associated collapse (EAC) is what happens when a person can’t stand or walk on their own during or after intense exercise. Earlier, it was referred to as ‘heat syncope’. While we can’t fully explain why it occurs, it’s believed to be due to a temporary drop in blood pressure upon standing up, caused by a combination of things like fluid loss, widening of blood vessels, and a decrease in blood vessel tightness related to problems with baroreflexes (automatic responses of your body to keep your blood pressure stable). This can result in decreased blood flow to the heart and fainting.
It’s important to distinguish EAC from other conditions linked with strenuous activities, as contrary to others, it’s usually a non-threatening condition. However, its symptoms might appear similar to those of sudden heart stoppage, heat stroke from exercise, low sodium levels due to exercise, or collapsing due to exercising with the sickle cell trait. A straightforward treatment for EAC is drinking fluids and assisted walking where medical staff help those collapse due to running to walk in specified safe zones. This approach helps to lower incidents that require medical action linked to EAC.
What Causes Exercise-Associated Collapse?
Exercise-associated collapse was previously referred to as heat fainting, and we’re still not entirely sure what causes it. It’s believed to be the result of a temporary drop in blood pressure when standing up, due to problems with the body’s natural response to changes in blood pressure. This can be linked to dehydration, blood vessels expanding, and a decrease in the force that pushes blood through your body.
These factors can lead to a reduce in the blood returning to the heart and a decrease in the heart’s pumping action. This can make people feel faint or even cause them to faint.
Risk Factors and Frequency for Exercise-Associated Collapse
Exercise-associated collapse, or sudden weakness after physical activity, mostly happens during endurance sports like marathons, ultramarathons, or triathlons. However, it can also happen during other kinds of strenuous activities like military training and team sports. Certain factors can increase the chances of experiencing this collapse:
- Having previously experienced collapse during exercise
- Being dehydrated
- Working out in hot, humid conditions
- Not getting enough calories
- Having chronic health problems
- Drinking alcohol
It’s important to note that age, sex, or ethnicity doesn’t seem to increase the risk of experiencing such a collapse.
Signs and Symptoms of Exercise-Associated Collapse
Exercise-associated collapse (EAC) often happens during intensive physical activities, especially in an outdoor setting like a marathon, triathlon, hiking, backpacking, or military field training. It often manifests when athletes stop their physical activity suddenly. This condition is more likely in hot and humid weather but can happen in other conditions as well.
If an athlete shows unusually high blood pressure and body temperature after a workout, other medical issues might be at play. For quick and efficient help for the athlete, it’s important to identify EAC and distinguish it from other exertion-related injuries.
There could be other reasons for the collapse like:
- Sudden cardiac arrest
- Exertional heat stroke
- Exercise-associated low sodium levels in the blood
- Exercise collapse linked with sickle cell trait
- Hypoglycemia related to insulin
- Seizures
- Anaphylaxis
The common symptoms of EAC include:
- Feeling lightheaded
- Blacking out or feeling faint
- Feeling tired and weak all over
- Changes in mental state, from slight confusion to significant alteration
In severe cases, the person can lose consciousness after they stop exercising.
Testing for Exercise-Associated Collapse
If an athlete collapses, the first step for medical professionals is to check five key areas: the airway, breathing, circulation, disability, and exposure. This is often referred to as an ABCDE screening. If these critical areas are found to be stable, doctors might ask for some background information to check for any changes in mental status. Measuring vital signs, which includes taking a rectal temperature to accurately measure the body’s internal temperature, is key to figuring out the possible underlying causes of the collapse, one of which could be overheating.
Treatment Options for Exercise-Associated Collapse
If you’re feeling sick due to a drop in blood pressure when you stand up, doctors will try to normalize your blood pressure and relieve your symptoms by taking certain steps. If your body temperature is not too high, they may ask you to lie down with your feet raised higher than your heart (this position is also known as the Trendelenburg position). Often, this alone can make you feel much better mentally and physically.
Once you’re at rest, and your symptoms have improved, you might be told to slowly start moving around with the help of a professional. Drinking fluids by mouth may also be suggested to increase the fluid in your blood vessels, which can help improve your blood pressure when you stand up. It’s important that the person helping you move around is trained to notice signs of conditions like Exhaustive Athlete Health (EAH) or heat-related injuries, as these could also be causing your symptoms and need different treatments.
However, if your mental state doesn’t improve after 5 minutes of lying down with your feet elevated, they may consider other causes for your condition. A vein may be accessed with a needle for fluid delivery. They might also do quick tests to check your electrolyte levels and blood sugar because low blood sugar and certain electrolyte imbalances can also cause symptoms. If your symptoms continue, or if you have a high body temperature, low blood pressure, or a fast heart rate, the doctor may suggest moving you to a facility that can provide more advanced care.
What else can Exercise-Associated Collapse be?
EAC, or Exertional Collapse, is a type of physical injury that can occur due to intense physical activity. However, it should only be diagnosed after ruling out other possible causes of physical strain or collapse. It’s important for health care professionals to follow specific assessment steps to rule out other possibilities:
- Using a systematic method, like ABCDE, can help rule out other serious factors, like a heart attack.
- Measuring a person’s temperature (through a rectal reading) is vital to verify if the person is suffering from conditions related to extreme body temperatures, like heatstroke.
- Immediate testing for electrolytes and blood sugar levels can help determine if the person collapsed due to factors like low sodium related to exercise (known as exercise-associated hyponatremia) or low blood sugar (exertional hypoglycemia).
- Knowing the person’s medical history is critical in checking for other risk factors. For instance, having a sickle cell trait can cause exercise collapse specific to people with this condition, known as ECAST. Other considerations are a history of epileptic seizures or allergies, both of which can potentially trigger an event of collapse.
What to expect with Exercise-Associated Collapse
Most athletes recover quickly with only minor treatments and don’t need to be treated at a hospital. In a study involving participants of the Gothenburg half marathon, only about 1.19 to 2.21 per 1000 required more intervention than just walking around and drinking plenty of fluids.
If an athlete needs more advanced care, it usually means there’s another underlying health issue causing their symptoms. This would mean they need a more thorough examination. The most common reasons for needing advanced care were overheating (hyperthermia), low salt levels in blood (hyponatremia), and low blood sugar (hypoglycemia).
Possible Complications When Diagnosed with Exercise-Associated Collapse
EAC, or exercise-associated collapse usually has few direct complications. Most people fully recover with minor treatments and experience little to no long-term effects. However, if you’ve had EAC before, you’re more likely to have it again in the future. It’s important to note that any injuries from falls related to EAC are considered secondary effects. This means they’re not caused by the initial collapse itself.
Common Outcomes:
- Full recovery with minor interventions
- Potential for repeat episodes in the future for those with a history of EAC
- Injuries from related falls as secondary effects
Preventing Exercise-Associated Collapse
If you have a history of long-term health problems, are often dehydrated, eat less than you should, or live in a hot or humid climate, you might be at a higher risk for a condition called EAC. EAC refers to a state where your body has difficulty cooling itself down, which can be dangerous. One way you can lower your risk is by avoiding drinking alcohol before participating in endurance events like marathons or long-distance biking. Alcohol can affect your body’s ability to regulate its temperature, increasing the risk of EAC.
