It’s common for stomach bugs or gastrointestinal illnesses to worsen at night. There are a few reasons why this tends to happen:
Dehydration
Vomiting and diarrhea from a stomach bug can lead to dehydration as your body loses fluids. Dehydration often gets worse throughout the day and peaks at night. Lying flat to sleep can make nausea and vomiting worse.
Disruption of circadian rhythms
Your digestive system follows a natural daily rhythm like the rest of your body. Digestion tends to be more active during the day and slows down at night. A stomach bug can disrupt this cycle, leading to more symptoms at night.
Inability to distract yourself
During the day, you may be able to distract yourself from gastrointestinal symptoms by working, watching TV, etc. At night, there are fewer distractions so you notice the symptoms more.
Fatigue
Fatigue from illness, along with loss of sleep at night, can make you feel worse overall. This compounds the impact of the stomach bug.
Medication wearing off
If you take medication for a stomach bug, it may start wearing off during the night. This allows symptoms to flare up again before your next dose.
Changes in gut bacteria
Some research suggests shifts in gut bacteria over a 24-hour cycle may contribute to worsening of certain gastrointestinal conditions at night.
Tips to manage a stomach bug at night
Here are some tips to help cope if your stomach bug worsens at night:
- Stay hydrated – Sip small amounts of water, electrolyte drinks, or broth throughout the day and night.
- Try medications – Over-the-counter antidiarrheals, antacids, or antiemetics may provide some relief of symptoms.
- Eat bland foods – Stick to the BRAT diet (bananas, rice, applesauce, toast).
- Sleep propped up – Use pillows to stay propped up at a 30-degree angle, which can help minimize nausea.
- Use ginger – Ginger tea, candies, or supplements may ease nausea and vomiting.
- Distract yourself – Listen to calming music or podcasts.
- Practice good sleep hygiene – Keep lights dim at night, avoid screen time before bed, etc.
- Call your doctor if dehydrated or symptoms persist > 48 hours, especially with bloody diarrhea, high fever, etc.
How long do stomach bugs last at night?
Most acute gastrointestinal illnesses last 24-48 hours at most. Severe symptoms generally improve each day. But it’s common to still have some abdominal pain, nausea, diarrhea or other lingering symptoms for 3-7 days.
When to seek medical attention
See a doctor right away if you experience:
- Bloody diarrhea or black/tarry stools
- No urine for 8 hours or very dark urine
- Fever over 102 F
- Persistent vomiting making it difficult to keep liquids down
- Severe abdominal pain or tenderness
- Signs of dehydration – dry mouth, lightheadedness, lack of tears, etc.
- Symptoms lasting more than 48 hours in adults or 24 hours in kids
- Weakness or fatigue lasting more than a day
Signs of dehydration are especially concerning in infants, small children, the elderly, pregnant women, and those with weakened immune systems. Seek medical advice if you are at all concerned about the severity of your or your child’s symptoms.
What causes stomach bugs to get worse at night?
Stomach bugs or viral gastroenteritis can be caused by several different viruses:
- Norovirus – This is the most common cause of viral gastroenteritis. It spreads very easily on cruise ships, in schools, etc.
- Rotavirus – Common cause of severe gastroenteritis in infants and young children. Less common in adults due to prior exposure.
- Adenovirus – Causes 10% of gastroenteritis cases, mostly in children.
- Astrovirus – Accounts for up to 10% of cases, more common in children than adults.
Other causes include food poisoning from bacteria or toxins, parasites like Giardia, medications, and chronic conditions like IBS. The contagious stomach bugs caused by viruses are notorious for worsening symptoms at night.
Conclusion
It’s very common for gastrointestinal bugs to worsen during the nighttime. Reasons for this include dehydration, changes in digestive rhythms, fatigue, and inability to distract yourself from the symptoms while trying to sleep. Tips to manage nighttime worsening include staying hydrated, taking medications, eating bland foods, and propping yourself up in bed. Most acute stomach bugs last 24-48 hours but can take longer to fully resolve. Seek medical attention if you experience any concerning or prolonged symptoms, especially signs of dehydration.