When the stomach bug enters a household, it can seem like vomiting often starts in the middle of the night – whether it’s you or your kids.
That can mark the beginning of a few exhausting days. Bed linen and pyjamas need to be changed, and vomit must be cleaned off the floor at all hours of the day and night.
But is this actually how it works biologically? Are there any studies or evidence showing that people get sick more often at night?
No, not according to the research, Ketil Størdal tells Science Norway. He is a paediatrician and researcher specialising in gastrointestinal diseases in children at the University of Oslo's Institute of Clinical Medicine.
"Based on what we find in the research, there's no evidence showing a daily pattern for when symptoms begin," he says.
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There could still be a real difference between night and day, but there is little data on this. It's therefore uncertain.
"It's hardly been studied," says Størdal.
But he believes it could be interesting to investigate.
"I'm not aware of that"
We also asked the Norwegian Institute of Public Health (NIPH) about this, but they were unable to provide a clear answer.
"I am not aware that there's a greater likelihood of symptom onset at night than during the day with viral gastroenteritis," Hilde Marie Lund, a doctor at NIPH, writes in an email to Science Norway.
There are several viruses that cause what we call the stomach bug, medically known as gastroenteritis. We will return to some of them.
An illustration showing norovirus.(Image: Shutterstock / NTB)
What happens inside the body?
Ketil Størdal explains that the stomach, intestines, and our immune system all go through different rhythms over the course of a day.
"The function of the gastrointestinal system depends on what we're otherwise doing, so it's clearly interesting to gain a better understanding of what is happening when we get an acute infection," he tells Science Norway.
An unrealistic depiction of the stomach bug.(Stock photo: Shutterstock / NTB)
"In that case, it can be useful to examine when the symptoms actually start," he adds.
Can we really sense when symptoms start?
Many factors influence how we experience illness, and we are not always fully aware of what is happening in our bodies.
For instance, it may be difficult to pinpoint the exact moment when symptoms like nausea begin, Størdal explains.
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"It can feel like it often starts at night," he tells Science Norway. "It's easier to ignore if you're busy doing something else."
Other viruses
Størdal highlights that rotavirus is the stomach flu virus responsible for the most severe illness and the most hospitalisations globally. The rotavirus vaccine, which was introduced into the Norwegian childhood vaccination programme in 2014, has been a major success.
"The vaccine protects very well, which means we see a change in patterns such as severe infections," he says.
Hospitalisations due to gastrointestinal infections in children have dropped by 75 per cent since 2014/2015, Størdal tells Science Norway.
He points out that norovirus has largely taken over from rotavirus.
"Norovirus has a slightly shorter but more intense course. It passes more quickly," he says.
