In life-threatening emergencies, the human brain can trigger 'hysterical strength'—a surge of adrenaline that allows people to lift objects as heavy as cars.

Hysterical strength is a documented phenomenon in which individuals perform feats of physical power far beyond their normal capabilities during high-stress situations. One famous example occurred in 1982 when Angela Cavallo lifted a 1964 Chevrolet Impala off her son after the car fell from its jacks. Another instance in 2006 involved Lydia Angyiou, who fought off a polar bear in Northern Quebec to protect her children. These events are driven by the 'fight-or-flight' response, regulated by the hypothalamus.When the brain perceives a mortal threat, it signals the adrenal glands to release a massive flood of epinephrine and norepinephrine into the bloodstream. This surge increases heart rate, blood pressure, and oxygen intake while redirecting blood flow to the skeletal muscles. Under normal conditions, the Golgi tendon organs act as a fail-safe, inhibiting muscle contraction to prevent the body from tearing its own tissues or breaking bones. Adrenaline effectively suppresses these inhibitory signals, allowing the body to access its absolute physical potential.While humans typically use only about 60% of their muscle capacity during maximal exercise, hysterical strength can push this near 100%. However, this comes at a significant cost because the skeletal system is not designed to handle such extreme loads. Survivors of these incidents frequently report severe muscle tears, hairline fractures, and total physical exhaustion once the adrenaline dissipates. Research into this area remains challenging because scientists cannot ethically replicate life-threatening stress in a laboratory setting.