Safe summer travel: thermoregulation and infant protection in the car

Managing an infant during summer travel is a critical area of focus in perinatal and pediatric care, with important implications for safety, thermoregulation, and comfort. Prolonged heat exposure—particularly inside vehicles—poses a significant risk of hyperthermia, dehydration, and heat stress. These conditions develop much more rapidly in newborns than in adults due to their reduced thermal compensation capacity.

Sun radiation and vehicle interior heating

Sunlight is composed of visible, infrared (IR), and ultraviolet (UV) radiation, all of which penetrate car windows to varying degrees depending on the glass type and any UV-blocking treatments applied. Standard tempered side windows allow most visible and infrared radiation to pass through, leading to rapid interior heating. While UVB rays are largely blocked, a significant amount of UVA radiation (320–400 nm) can still penetrate, potentially affecting the skin and eyes of pediatric passengers.

Multiple studies have shown that the interior temperature of a car can rise sharply within minutes—even on seemingly mild days. The greenhouse effect created by infrared radiation, combined with poor ventilation and a sealed cabin, can result in temperatures exceeding 40–45°C (104–113°F), even when the outside temperature is only 22–24°C (71–75°F) (McLaren et al., 2005).

Newborn Physiology and Hyperthermia Risks

Newborns have a relatively large surface area-to-weight ratio and an immature thermoregulatory system, with limited ability to sweat or dissipate heat. In this context, hyperthermia can develop extremely quickly, leading to severe neurological and metabolic complications.

Essential Recommendation: never leave an infant alone in a car—not even for a few minutes. Always use certified anti-abandonment systems, as required under current regulation ECE R129/03.

Managing car air conditioning

Vehicle air conditioning should be managed gradually and carefully to avoid physiological imbalances in infants. Setting the temperature too low can lead to thermal shock, respiratory mucosal irritation, and general discomfort. Practical recommendations include:

• Turn on the A/C 5–10 minutes before placing the baby in the car.
• Avoid a temperature difference (ΔT) of more than 4–4.5°C compared to the outside.
• Maintain a cabin temperature of at least 25°C (77°F).
• Avoid directing airflow straight at the infant; aim vents upward instead.

The air recirculation function should only be activated after reaching the desired temperature to help stabilize the internal microclimate. Air quality inside the vehicle is also crucial for infant respiratory health, as air filters can harbor microorganisms, allergens, and fine dust.

Summer Protective Accessories

The use of sunshades on rear side windows is strongly recommended to:

• Reduce direct solar radiation on the infant.
• Minimize local heating of the car seat.
• Protect the infant’s skin from harmful UV rays, which can still pass through glass.

The use of the summer cover is particularly recommended for newborns with sensitive skin or atopic dermatitis.

Managing an infant during summer car travel requires careful planning and specific protective measures, taking into account the infant’s physiological characteristics and seasonal environmental risks. Proper air conditioning, use of protective accessories, thermal monitoring, and constant supervision are essential tools to ensure safety, comfort, and health for infants on the move.