Q: My child has the flu and their temperature dropped to 35.7°C (96.3°F) while sleeping on Day 4. Is this normal?
Medically reviewed by Sang Hyun Ahn, MD
Content edited by Myeongchan Kim, MD
This post is a dramatization of a question and answer session experienced by our actual medical reviewers. Please note that this content is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.
Question:
My child was diagnosed with the flu, and their fever started four days ago. It is now past midnight, and while they were sleeping, their temperature was in the 36°C (around 97°F) range earlier. When I just checked again, it had dropped to 35.7°C (96.3°F). Is this safe, or is it too low? Does this mean the fever is finally breaking? Should I wake them up to measure it again, or is it fine to just let them sleep? I was so worried about the high fever before, and now I am anxious because the temperature seems so low.
Answer:
It is completely understandable to feel caught off guard when your child’s temperature suddenly dips after days of managing a high flu fever.
Here is what you need to know about why this happens and what to do tonight:
1. A lower temperature during sleep is normal
Natural body rhythm: During deep sleep, especially between midnight and early morning, the body's internal thermostat naturally lowers your child's temperature by about 0.5°C to 1.0°C (1°F to 2°F).
Normal sleeping range: A temperature between 35.5°C and 36.5°C (95.9°F to 97.7°F) while a child is sleeping soundly is generally considered within the normal physiological range.
The fever is resolving: As the immune system gains control and the fever breaks (defervescence), body temperatures can temporarily dip slightly lower than usual.
2. What you should do right now
Let them sleep: If your child is resting comfortably, do not wake them just to retake their temperature. Sleep is essential for their immune system to recover from the influenza virus.
Keep them comfortable: Make sure they are not covered in excessively heavy blankets, but keep the room at a comfortable temperature so they do not feel chilled.
Check again in the morning: Re-measure their temperature after they wake up naturally.
3. Warning signs to look out for
You only need to wake your child or seek immediate medical care if you notice concerning symptoms, such as:
Severe, uncontrollable shivering or drenching cold sweats.
Bluish or pale lips, nail beds, or skin.
Fast, labored, or difficult breathing.
Difficulty waking up, extreme lethargy, or confusion when aroused.
Next Steps for Tomorrow
Flu fevers typically begin to resolve by Day 4 or 5. Once your child wakes up, check their temperature, encourage fluids to support hydration, and observe their energy levels.
If their fever returns and spikes again, lasts longer than 5 days, or if they show signs of dehydration or persistent lethargy, contact your pediatrician or the healthcare provider who initially evaluated them for further guidance. For tonight, as long as they are sleeping peacefully, allow them to get the rest they need.
For extra peace of mind and clear guidance when tracking your child's symptoms, the FeverCoach app is always there to help.
