In a finding that may surprise many parents, doctors have warned that infants rarely sweat, and that excessive perspiration may indicate underlying health issues, particularly congenital heart disease, one of the most serious conditions in early childhood.

According to Dr. Sarmad Mazhar, a UK-based family physician and health educator, a baby’s body does not regulate temperature like that of an adult, as their sweat glands are still developing. He explained that sweating heavily, especially during sleep or feeding, is not typical and may suggest problems related to the heart, endocrine system, or metabolism.

The doctor added that hyperthyroidism—an overactive thyroid gland—can lead to increased body heat and sweating. Another possible cause is cystic fibrosis, a genetic disorder that affects the body’s salt regulation, leading to thick mucus buildup in the lungs and respiratory difficulties.

Dr. Mazhar emphasized that parents should never ignore persistent or unusual sweating, especially when accompanied by labored breathing, poor feeding, or slow growth, as these may be signs of heart or respiratory conditions requiring urgent medical evaluation.

He concluded by stressing that early detection can save lives, urging parents to monitor any unusual changes in their baby’s health and seek medical attention without delay.