Holding your breath is something many people do instinctively in response to pain, pressure, or discomfort. Whether you’re lifting a heavy weight, jumping into cold water, or steeling yourself before a medical procedure, holding your breath is a natural reaction. But what actually happens in your body when you hold your breath, and why does it often cause discomfort or pain?
When you hold your breath, it leads to a series of physiological changes and reactions that explain the discomfort that often accompanies breath-holding. Though usually harmless in the short-term, extended or repetitive breath-holding can sometimes lead to loss of consciousness or even injury. Understanding the science and physical effects of holding your breath can help you avoid undesirable outcomes.
What Happens When You Hold Your Breath?
Breathing is an automatic process controlled by the respiratory centers in the brainstem, which continually regulate your breathing rate and depth according to the body’s needs. When you make a conscious decision to hold your breath, you temporarily override this automatic regulation. But your respiratory centers immediately kick into action to get you breathing again.
Specifically, holding your breath leads to these key effects:
- Decreased oxygen (O2) and increased carbon dioxide (CO2) in the blood. When you stop breathing, your lungs stop taking in fresh oxygen. At the same time, cells throughout your body continue producing CO2 as a byproduct of metabolism. This leads to declining blood oxygen levels and rising blood CO2 levels.
- Increased breathing urge and reflex. Specialized chemoreceptors in the carotid arteries and medulla oblongata detect decreases in blood oxygen and increases in blood CO2. In response, they trigger an urgent impulse to breathe.
- Constriction of blood vessels. Lower oxygen causes blood vessels in the extremities to constrict, diverting blood to the heart, lungs, and brain. This allows the most essential organs to have continued oxygen supply.
- Increased heart rate. The heart speeds up to circulate the diminished oxygen supply to vital tissues.
- Blood pressure changes. Initially blood pressure increases, then progressively drops as oxygen runs low.
- Straining of respiratory muscles. Muscles between the ribs (intercostals) and in the neck contract forcefully in an effort to draw in air.
As long as breath-holding doesn’t persist too long, these responses effectively redistribute oxygenated blood flow and trigger resumption of normal breathing. But when you forcibly override the breathing reflex for an extended period, the physiological disturbances become more pronounced and distressing.
Why Does Holding Your Breath Hurt?
The combination of low oxygen, high CO2, and straining respiratory muscles lead to several forms of discomfort and pain when you hold your breath. Common sensations include:
The urgent need to breathe is triggered by accumulating carbon dioxide in your blood, which is detected by chemoreceptors. This creates an increasingly panicky, air-hungry feeling the longer you hold your breath.
Your intercostal muscles connect your ribs. As these muscles strain harder to inflate your chest, they can spasm painfully. The chest muscles tire from overexertion.
Depriving your brain of fresh oxygen can lead to temporary hypoxia. This causes an uncomfortable lightheaded or dizzy feeling.
Falling oxygen levels cause cerebral vasoconstriction, squeezing the blood vessels in the brain. This can trigger a throbbing headache.
Your heart rate speeds up in an effort to supply oxygen to your tissues. The pounding sensation from a faster heartbeat feels unpleasant.
With reduced peripheral circulation, your extremities don’t get enough oxygenated blood. This can cause numbness and tingling.
Low oxygen impairs retinal cell function, potentially causing temporary visual disturbances.
If breath-holding causes cerebral hypoxia to become severe, you may lose consciousness and collapse.
What’s Considered Normal vs. Harmful Breath-Holding?
The human urge to breathe is extraordinarily strong. Few people can voluntarily suppress breathing for more than 1-2 minutes without profound discomfort. World champion free divers who train extensively to hold their breath can still only manage 4-5 minutes before needing to breathe again.
So how long can you safely hold your breath? Here are some general timelines:
30-90 seconds – Uncomfortable but not harmful for most healthy adults. Can leave you momentarily dizzy or lightheaded after resuming breathing.
2-4 minutes – Risk of fainting, blacking out, or seizure, especially if hyperventilating before breath-holding or doing strenuous activity like underwater swimming. Puts severe strain on the cardiovascular system.
Beyond 4 minutes – High risk of serious health impacts including arrhythmias, hypoxic brain damage, loss of consciousness, and drowning if underwater. Pushing breath-holding to this extreme is extremely dangerous.
However, effects can vary based on your health status and the manner of breath-holding. For example, breathing pure oxygen first allows longer breath-holds. Conversely, activities like weightlifting that increase oxygen demand decrease breath-hold tolerance.
Children often accidentally hold their breath when upset or tantruming – breath-holding lasting over 30 seconds can be dangerous for them. Chronic, repetitive breath-holding may also have detrimental neurological effects in children.
When to Worry About Breath-Holding
Occasional voluntary breath-holding within reasonable time limits is usually harmless for healthy individuals. But in some cases, breath-holding can signal an underlying medical problem requiring evaluation:
- Passing out or seizures with breath-holding
- Inability to take a full breath or catch your breath
- Chronic breath-holding habits
- Associated chest pain or cardiovascular symptoms
- Lightheadedness or altered mental status after breath-holding resolves
Talk to your doctor if you experience any of these red flag symptoms with breath-holding. Sudden loss of consciousness requires prompt medical assessment to check for injury and rule out cardiac arrest, stroke, or neurological causes.
When Breath-Holding May Be Used Medically
Though extreme breath-holding is seldom advisable, trained medical staff may instruct you to briefly hold your breath for certain procedures where movement needs to be minimized, including:
- Radiation therapy
- MRI scans
- Cardiac stress testing
- Pulmonary function testing
- Abdominal ultrasound exams
- Surgical procedures on the chest or abdomen
They will coach you on proper breath-holding technique and limit the duration to avoid problems. Some doctors may also recommend breath-holding exercises using a specific breathing pattern to maximize the air retained in your lungs. This requires training to perform correctly under medical guidance. Attempting to self-treat medical conditions like asthma or hypertension with breath-holding is risky and should be avoided.
How to Hold Your Breath Safely
If you voluntarily hold your breath recreationally – whether swimming underwater, for meditation, or another purpose – keep these tips in mind:
- Start with good oxygenation. Take a few deep breaths before holding your breath to maximize lung capacity.
- Use a timer or watch. Tracking your breath-hold time prevents accidentally exceeding safe limits.
- Never hyperventilate first. Overbreathing blows off too much CO2, delaying the natural breathing reflex.
- Avoid pushing to extremes. Progress gradually from comfortable breath-holds of under 1 minute initially.
- Don’t breath-hold alone. Have a spotter present in case you faint or black out.
- Listen to your body. Stop immediately if you feel chest pain, lightheadedness, blurry vision, etc.
With knowledge of your personal limits and prudent precautions, breath-holding can be performed safely for short periods. But take care not to overdo it.
Other Causes of Breathing Discomfort
While breath-holding itself often causes transient discomfort, some medical conditions can also make normal breathing painful or difficult:
Inflammation and fluid buildup in the lungs interferes with oxygen exchange and makes breathing uncomfortable. It may hurt to inhale deeply.
The pleural membranes around the lungs become inflamed, causing sharp chest pain on breathing.
Chronic obstructive pulmonary disease like emphysema involves narrowed airways that make breathing a struggle.
A blood clot in the pulmonary arteries causes sudden shortness of breath and chest pain.
Collapsed lung from air leakage into the pleural space causes acute, stabbing chest pain with breathing.
Fluid buildup in the lungs from congestive heart failure leads to shortness of breath, even at rest.
So while breath-holding can directly provoke discomfort through its effects on oxygen and CO2 levels, difficulty breathing may also indicate an underlying respiratory or cardiovascular problem requiring medical care.
Holding your breath triggers a coordinated physiological response designed to get you breathing again. The resulting low oxygen, high CO2, and strained breathing muscles quickly cause air hunger, chest tightness, lightheadedness, and other unpleasant sensations designed to force you to resume breathing. While generally harmless for short periods, extended breath-holding can deprive the brain and heart of oxygen, leading to fainting or loss of consciousness. To avoid harm, restrict voluntary breath-holding to less than 1-2 minutes and refrain from hyperventilating beforehand. Listen to your body and stop immediately if you develop concerning symptoms. With prudence, breath-holding can be performed transiently and safely by most healthy individuals.