Common winter sleep habit found to be harmful for your respiratory health: Research

As temperatures drop and nights turn colder, many people instinctively pull their blankets higher for warmth. For some, covering the face becomes a familiar way to fall asleep faster, shut out the cold and create a sense of security. While the habit feels natural and comforting, research and expert observations show that sleeping with the face covered may interfere with breathing, affect sleep quality, and strain respiratory health—especially during winter, when airways are already vulnerable.

Pulling a blanket over the face often creates a cocoon-like environment that feels warm and quiet. Reduced light, muted noise and a sense of protection help many people settle into sleep more easily. However, researchers point out that the calming psychological effects do not reduce the physical risks associated with reduced airflow and trapped heat.

A peer-reviewed study titled “Consequences of getting the head covered during sleep” noted that covering the head or face limits the movement of fresh air and increases exposure to recycled warm air. The study found that the air near the face becomes richer in carbon dioxide and significantly warmer when the head is covered, altering both oxygen intake and thermal comfort.

How This Habit Affects Breathing

When blankets encircle the nose and mouth, exhaled air gets trapped in a small enclosed space. Over time, this raises carbon dioxide levels and lowers the flow of fresh oxygen.

Findings from studies using breathing mannequins showed a high “re-breathing rate” of carbon dioxide when the head stays under covers. This means a person may repeatedly inhale their own exhaled air.

Reduced ventilation may lead to:

• light or disturbed sleep
• morning fatigue
• headaches or dizziness
• difficulty concentrating

People with asthma, COPD, allergies or sinus congestion may experience worsened symptoms due to restricted airflow and warmer, humid air close to the face.

Impact on Skin and Temperature Regulation

Covering the face creates a warm, moist environment that can irritate the skin. Moisture, sweat and friction against fabric may clog pores, and blankets can accumulate oils, dust, allergens and bacteria. Pressing such fabric against the face for hours may lead to breakouts or inflammation, particularly in sensitive skin.

Body temperature naturally drops at night to support restorative sleep. When heat cannot escape because the face is covered, overheating may occur. People may experience night sweats, restlessness, dehydration or irregular sleep patterns. Sleep specialists note that disrupted temperature regulation can affect sleep depth and morning alertness.

Why Winter Increases Respiratory Vulnerability

Winter itself adds several stressors:

• cold, dry air irritates airways
• indoor heating reduces ventilation
• higher pollution levels in cities can strain breathing
• respiratory infections are more common

With these factors already affecting the lungs, the additional challenge of reduced oxygen flow under a blanket may worsen discomfort or respiratory strain.

Who Is at Higher Risk?

While healthy adults may experience mild or occasional discomfort, certain groups face greater risk:

• individuals with chronic respiratory diseases
• those with sleep apnoea
• people prone to breathing difficulties
• infants and young children

Paediatric guidelines strongly warn against face-covering for babies and toddlers, as they cannot adjust bedding if airflow becomes restricted. Research on infants sleeping with the head covered has shown increased carbon dioxide around the face and reduced arousal—factors linked to Sudden Infant Death Syndrome (SIDS).

Safer Ways to Stay Warm in Winter

Health authorities recommend alternatives that maintain warmth without restricting breathing:

• use layered blankets rather than placing them over the face
• wear warm sleepwear, thermal clothing or socks
• keep blankets tucked below shoulder level
• use breathable cotton bedding
• place a hot water bottle near the feet
• ensure some airflow in the room, if pollution levels allow
• use an eye mask for darkness instead of pulling blankets upward

These adjustments help retain comfort without impacting oxygen flow or temperature balance.

A face-covered sleep position may feel comforting in the cold, but research and expert observations highlight how it can reduce oxygen intake, increase carbon dioxide exposure, trap heat and irritate the skin. While healthy adults may not face severe immediate risk, the habit can still reduce sleep quality and morning energy. The dangers are much greater for those with respiratory conditions and for children.