6 surprising reasons you might feel sick in the morning, even if you're not pregnant

• Nausea is sometimes a symptom of pregnancy, but people feel sick in the morning for many reasons.
• For instance, it could be down to diet, lack of sleep, or anxiety.

If you're a woman, feeling sick in the morning is known as one of the first signs you're pregnant. But it's not the only reason you might feel queasy when you wake up.

"When we hear about morning sickness, most people's first thought is pregnancy," said Dr. Janice Johnston, the chief medical officer and cofounder of healthcare provider Redirect Health. "This is because morning sickness is a very common side effect in pregnancy, specifically in the first trimester, affecting about 7 in 10 pregnant women."

The reason morning sickness is so common is due to a particular hormone called human chorionic gonadotropin, or HCG. The body starts producing HCG as soon as the fertilized egg attaches to the uterine lining, which results in a feeling of queasiness, nausea, and can cause vomiting.

According to medical professionals, morning sickness, or a general feeling of nausea can be caused by a wide variety of things, including diet, lifestyle, and mental wellbeing.

1. Irregular sleeping

Having a disrupted sleep cycle, whether it's from insomnia, sleep apnea, or simply staying up too late, can affect our digestive systems, Johnston said.

"This can cause you to have a feeling of uneasiness in your stomach when you wake up in the mornings," she said.

According to Dr. Daniela Jodorkovsky, a doctor interviewed by Refinery29, a feeling of sickness is closely linked to our sleeping patterns. Not getting enough sleep disrupts the body's circadian rhythms — or body clock — which has been linked to numerous disorders and problems, including Alzheimer's, weight gain, and mental-health conditions including depression.

All our hormones are in a delicate balance. Some make us sleepy, like melatonin, and some, like ghrelin, control our appetite. So eating or sleeping at irregular times can have more of a prolonged impact than we realize.

General practitioner Dr. Nick Knight told GQ that the shock of waking up when you're exhausted can trigger a rapid spike in your "fight or flight" nervous system, which can trigger this feeling of nausea.

2. Low blood sugar

If your blood sugar is low, it can cause a feeling of low energy and weakness, Johnston said.

"Low blood sugar can come from a lack of eating well-balanced meals with fiber and complex carbs, or from skipping meals altogether," she said. "If you wake up with an upset stomach it may have been because you skipped dinner or simply did not eat enough the day before."

Jodorkovsky recommends eating something, even if you don't feel like it.

"While it sounds counterintuitive, eating a light snack or breakfast when feeling nauseated in the morning can alleviate the symptoms altogether," she said.

3. Acid reflux

Morning nausea can also be caused by your diet. For example, eating a big meal right before bed full of fatty foods might cause acid reflux, according to Johnston.

"Stomach acid can go up through the esophagus and cause a feeling of heartburn and sometimes an upset stomach," she said.

4. Dehydration

Knight, the doctor who spoke to GQ, said not drinking enough water can also be a reason you wake up feeling sick.

"Overnight it's easy to dehydrate (and exacerbated if you've had some alcohol)," he told the outlet. "When you take on fluid, the symptoms settle."

5. Anxiety

Anxiety can cause nausea, especially if there is an event coming up, like an important meeting.

"Our gut, or gastrointestinal system, is closely linked to our central nervous system and our brains," said Johnston, the Redirect Health cofounder. "These two systems communicate back and forth with each other, so when one is affected, the other will notice."

When feeling high stress or anxiety, certain hormones get released, she said. When they enter your digestive tract, it can affect digestion and cause an upset stomach.

"If you are laying in bed stressing about a test, or feeling anxious about an upcoming event, you may feel a sense of queasiness or nausea as a result," she said.

If anxiety is affecting your every day life and you're suffering frm panic attacks, it could be a sign of an anxiety disorder that needs to be checked by a professional.

6. Nasal congestion

Strangely, nasal congestion could also be a culprit. According to Healthline, a blocked nose or sinuses can put pressure on your inner ear, leading to an upset stomach and nausea.

Otherwise, Britian's National Health Service lists suggestions for nausea, including plenty of fresh air, peppermint or ginger tea, distractions like watching films, and smaller, frequent meals.

"Of course, if you have concerning symptoms like vomiting, weight loss, severe headaches, or abdominal pain, see your doctor," said Jodorkovsky.

This article was first published in December 2018 and has been updated to include more experts and examples.