Adrenaline can increase muscle strength by up to 50% during emergencies by temporarily overriding the body's natural safety limits.

When the amygdala detects a threat, it signals the hypothalamus to activate the sympathetic nervous system. This triggers the adrenal glands to release epinephrine, commonly known as adrenaline, into the bloodstream. This process is part of the fight-or-flight response, a physiological reaction first described by Walter Cannon in 1915.Adrenaline increases heart rate and dilates the bronchioles in the lungs to maximize oxygen intake. It also signals the liver to release glucose for immediate energy. Crucially, it suppresses the Golgi tendon organs—sensory receptors that normally prevent muscles from contracting with enough force to injure themselves or break bones.By blocking these inhibitory signals, your body can access nearly 100% of its muscle fiber potential, compared to the 60% typically used during intense exercise. This is the mechanism behind "hysterical strength," famously illustrated in the 2012 case of 22-year-old Lauren Kornacki in Virginia, who lifted a BMW off her father. However, because this state causes rapid ATP depletion and micro-tears in muscle tissue, the body cannot sustain it for long.The physical toll is substantial, often requiring days of recovery. Researchers at institutions like the University of Washington have studied how these chemical surges temporarily alter neuromuscular junctions. While the 50% increase is a commonly cited benchmark, the exact limit varies based on an individual's muscle mass and the intensity of their hormonal response.