Why does my eye twitch? Dr Amir Khan reveals the reasons behind 5 relatable but 'totally random' symptoms

Why does my eye twitch? Why can I only have one cup of coffee before needing the loo? Why do I only feel anxious at night? All valid questions, says Dr Amir Khan. Unless you're having other symptoms, though, it's unlikely you'd visit the doctor to talk about them.

And nor should you need to, as these are all common symptoms that, on their own, mean very little. However, it's good to know where some of our more bizarre bodily functions come from, and to check that they are not some of the vague symptoms we shouldn't ignore.

"Most of these symptoms are completely harmless, but if they're persistent or affecting your quality of life, that's when it's time to speak to your doctor," he says.

The doctor, who is a frequent guest on Lorraine and This Morning, and woman&home's resident GP, shared the answers to these questions and more in an Instagram video this week.

Why does my eye twitch?

If your eyelid is twitching, seemingly for no reason, like it's doing its "own little dance", there's no need to worry.

"That's called myochimia," he says. "It's a spontaneous, involuntary muscle contraction. Usually, of a particular muscle in the eyelid and triggered by things like caffeine, fatigue, or stress."

It might feel odd, but it's a benign condition. The only reason to see a GP about it would be if it "spreads beyond the eye" or lasted for more than a few weeks.

Why do I always need the loo after a coffee?

If you need the loo immediately after your morning coffee, you're not alone, the doctor says. It's a very common symptom - and one that's linked to our gut health.

"Have you ever noticed how coffee goes straight through you, particularly first thing in the morning? That's thanks to your gastrocolic reflex, a natural response where stretching the stomach sends signals to the colon to get moving."

Caffeine makes this response stronger by stimulating the release of gastrin, a hormone that promotes digestion and contraction of the bowels, and increases movement in the gut overall.

"It's especially strong after fasting overnight," he adds. "It's not diarrhoea, it's just your gut waking up to its clock and doing its job."

Why do I get short of breath while talking?

If you regularly exercise and climb the stairs without an issue, you might be wondering why sometimes you can't hold a conversation without needing to take a deep breath.

"It could be a breathing pattern disorder, sometimes called dysfunctional breathing," explains Dr Khan. "This means your breathing is shallow, rapid, and mainly upper chest-based instead of coming from the diaphragm.

"It can be caused by chronic stress or anxiety, habitual overbreathing, or poor posture or poor vocal use."

Why do I only feel stressed or anxious at night?

Speaking of anxiety, the doctor says it's very common to have feeling of heighted stress, anxiety, or even pain at night, but be totally fine during the day.

As well as having more space to think when you're winding down for bed, Dr Khan says that hormone levels could be to blame for our intense emotions.

"Our cortisol levels drop in the evening. Cortisol is an anti-inflammatory hormone, so without it, pain and swelling can feel worse. Also, your circadian rhythm shifts, making your body more sensitive to stimuli at night," he says.

Why do I sweat when I'm nervous?

"Ever notice your hands, feet, or back start sweating just from nerves or stress? This is emotional sweating. It's involves sweat glands in your palms, soles, and armpits, and is triggered by your parasympathetic nervous system. That's the fight or flight response," the doctor explains.

While regular sweating from exercise helps cool the body down, emotional sweating happens due to psychological stress.

None of these symptoms is a sign that your body is "malfunctioning", says Dr Khan. "It's just doing its thing." The only reason to be concerned is if the symptoms last for longer than you'd expect or if you start experiencing them elsewhere in the body, too.