TV doctor Amir Khan has explained the science behind five common symptoms, what they mean, and when people should seek medical help. He shared a video on TikTok detailing the symptoms, which he said "feel totally random, but actually have a proper medical explanation."
Eyelid twitching and the gastrocolic reflex
Speaking about eyelid twitching, Dr Khan said: "You know when your eyelid starts twitching for no reason, like it's doing its own little dance? That's called myokymia. It's a spontaneous, involuntary muscle contraction, usually of a particular muscle in the eyelid, often triggered by things like caffeine, fatigue, or stress."
He added: "You don't need to worry. It's benign and self-limiting in most cases. But if it does spread beyond the eye or doesn't stop after a few weeks, speak to your GP."
Dr Khan also addressed why coffee can have a rapid effect on the bowels. He explained: "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."
Breathlessness and night-time symptoms
He noted that caffeine strengthens this reflex by stimulating gastrin release, a hormone that promotes digestion and increases movement in the gut. "It's especially strong after fasting overnight. It's not diarrhoea, it's just your gut waking up to its clock and doing its job," he said.
On feeling breathless while talking, Dr Khan said: "If you do feel short of breath just whilst talking, but are otherwise healthy, it could be a breathing pattern disorder, sometimes called dysfunctional breathing." He explained that this means breathing is shallow, rapid, and mainly upper chest-based instead of coming from the diaphragm, and it can be caused by chronic stress or anxiety, habitual over-breathing, or poor posture or vocal use.
Dr Khan also explained why some people with health conditions may feel worse in the evening. He said: "Your cortisol levels drop in the evening. Cortisol is an anti-inflammatory hormone, so without it, pain and swelling can feel worse." He added that the circadian rhythm shift makes the body more sensitive to stimuli at night, and the brain has fewer distractions, so it notices every heartbeat, ache, or worry more clearly.
Emotional sweating and when to see a doctor
Finally, Dr Khan discussed emotional sweating, which affects the hands, feet, or back due to nerves or stress. He explained: "It involves eccrine sweat glands mostly in your palms, soles, and armpits, and is triggered by your parasympathetic nervous system. That's the fight or flight response."
Concluding, he said: "So all of this isn't your body malfunctioning, it's just doing its thing. 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."
