Do teenagers with CHD show different symptoms than infants? 

Yes, the symptoms of congenital heart disease (CHD) in teenagers are significantly different from those seen in infants. While infants primarily show signs related to the high energy cost of feeding and growing such as rapid breathing and poor weight gain teenagers typically experience symptoms triggered by physical exertion or changes in heart rhythm. As the body matures, the heart’s compensatory mechanisms shift, moving from the metabolic struggles of early life to the functional and electrical challenges of adolescence. 

What We will cover in this Article 

• The physiological shift from growth issues to exercise intolerance 

• Identifying cardiac symptoms in active adolescents 

• The role of heart rhythm problems (arrhythmias) in teenagers 

• How puberty and rapid growth spurts impact heart function 

• Comparison of symptoms across different age groups 

• Recognising late onset symptoms in previously undiagnosed teens 

From Feeding Struggles to Exercise Limits 

In infancy, the most demanding task for a baby is feeding. Consequently, CHD symptoms in babies are often seen during or after milk intake. In contrast, a teenager’s body has already completed its most intensive growth phase, and the heart is now challenged by different stressors, such as competitive sports, hormone changes, and a larger body mass. 

Teenagers with CHD often appear perfectly healthy at rest. However, when they push their bodies during physical education or hobbies, the structural limitations of their heart become apparent. This is often the time when previously ‘mild’ defects or the long-term effects of earlier surgeries begin to manifest as new physical limitations. 

Common Symptoms in Teenagers 

While infants may turn blue or breathe fast while sleeping, teenagers are more likely to report the following symptoms during or after activity: 

Exercise Intolerance and Fatigue 

A teen may notice they cannot keep up with friends during sports. They might feel unusually breathless or exhausted compared to their peers after the same level of activity. This happens because the heart cannot increase the amount of blood it pumps (cardiac output) to meet the muscles’ demand for oxygen. 

Palpitations and Rhythm Issues 

Adolescence is a common time for heart rhythm problems to emerge. The heart may feel like it is racing, fluttering, or skipping beats. This can be caused by natural electrical changes during puberty or by scar tissue from heart surgeries performed years earlier. 

Chest Pain and Dizziness 

Unlike adults, where chest pain often signals a heart attack, in teenagers with CHD, it can indicate that the heart muscle is not getting enough oxygen during stress. Dizziness or fainting (syncope) during exercise is a significant red flag that requires immediate clinical review. 

Comparison of Age-Related Symptoms 

The following table highlights the distinct ways CHD presents as a child grows into a teenager. 

Feature	Infant Presentation	Teenager Presentation
Primary Trigger	Feeding and crying	Exercise and sudden emotion
Respiratory Signs	Constant fast breathing (Tachypnea)	Shortness of breath only on exertion
Physical Signs	Sweating while eating, blue lips	Swelling in ankles, chest pain, fainting
Growth/Weight	Failure to thrive (weight plateau)	Often normal growth; reduced stamina
Heart Rhythm	Usually consistent fast rate	Palpitations or ‘flip-flopping’ feeling
Urgency Signs	Floppiness, grunting	Collapse during sports, chest pressure

Why Symptoms Change with Puberty 

The rapid growth spurts and hormonal changes of puberty place additional strain on a heart that is already working differently. As a teenager grows taller and heavier, the heart must pump blood over a larger area. If a valve is slightly narrow or a chamber is slightly weak, the increased demand of a larger body can cause symptoms that were not present when the child was smaller. 

Furthermore, the transition into adolescence often involves a move toward more competitive and high-intensity sports, which acts as a ‘stress test’ for the heart’s structural integrity. 

To Summarise 

Teenagers with CHD show very different symptoms than infants. While babies struggle with growth and feeding, adolescents are more likely to experience exercise intolerance, palpitations, and fainting. These changes are driven by the physical demands of a maturing body and the long-term effects of structural heart defects. Regular follow-up with a specialist adult congenital heart disease (ACHD) team is vital to monitor these shifting symptoms as a child moves into adulthood. 

If you experience severe, sudden, or worsening symptoms such as collapsing during exercise or feeling your heart race uncontrollably, call 999 immediately. 

Authority Snapshot (E-E-A-T Block) 

This article was reviewed by Dr. Stefan Petrov, a UK-trained physician with experience in general medicine, surgery, and emergency care. Dr. Petrov’s clinical background includes performing diagnostic procedures and managing acute presentations in both hospital and intensive care settings. His expertise ensures this guide to adolescent CHD symptoms is accurate and follows the 2026 NHS and NICE safety frameworks.