When confronted with danger, the human body reacts instinctively, as demonstrated by these seven unusual reactions that occur during life-or-death situations.
Before you have a chance to make a conscious decision, a series of automatic responses start to take over—some imperceptible, others unsettling, and a few quite peculiar.
While many people are familiar with the ‘fight or flight’ response, researchers have identified additional survival mechanisms that activate quietly in potentially life-threatening situations.
Some of these responses enhance your senses, others diminish pain, and a few even alter your perception of time. These reactions collectively showcase the extraordinary lengths to which the human body will go to ensure survival.
So, let’s delve into the seven strange reactions your body may undergo when faced with danger—though with any luck, you’ll never encounter these symptoms. Nonetheless, death remains life’s only certainty.
Among these responses, one of the most fascinating involves the perception of time slowing down during serious accidents. A study by the University of Iowa College of Medicine discovered that 70 percent of individuals in life-threatening situations experienced this sensation. Research published in PLOS One suggests that fear prompts the brain to capture more detailed memories, possibly causing this effect.
Immersing your face in cold water activates the ‘mammalian diving reflex’, which slows the heart rate and redirects oxygen to essential organs. British physician Edmund Goodwin first identified this reflex in 1786. Additionally, a 2021 Frontiers in Psychiatry study indicated that it might also alleviate anxiety.
In critical situations, the sensation of pain can be temporarily muted, enabling escape. Dan Baumgardt from the School of Psychology and Neuroscience at the University of Bristol, noted in The Conversation the significance of the brain’s periaqueductal gray in this process. “Ever picked up something in the kitchen that you suddenly realise is extremely hot?” he wrote.
Fear triggers pupil dilation, permitting more light to enter and temporarily enhancing vision. A 2016 study in the Journal of Traumatic Stress observed greater pupil dilation in individuals with post-traumatic stress disorder (PTSD) when exposed to threatening images. Earlier research has linked pupil size to cognitive effort.
According to a 2019 study by researchers in Switzerland and the United States, nightmares might help prepare you for real-world danger by improving your fear responses while awake. “Dreams may be considered as a real training for our future reactions and may potentially prepare us to face real life dangers,” researcher Lampros Perogamvros stated.
A 2008 study in Nature Proceedings found that people exhibited increased amygdala activity—which triggers the fight-or-flight response—when exposed to sweat from first-time skydivers compared to sweat from exercise. These findings suggest that humans can subconsciously detect fear through scent without being consciously aware of it.
Shaking in fear is due to adrenaline, not weakness. The Fixel Institute for Neurological Diseases explains that adrenaline causes muscles to tighten, increases heart rate, and redirects blood flow. The resulting tremors represent excess energy, preparing the body for swift action.