 Common responses include: pupil dilation (93 %); changes in heart rate (100 %), including increases (56 %), decreases (13 %), and variable responses (31 %); changes in blood pressure (84 %), including hypotension (34 %), hypertension (28 %), and general instability (22 %); changes in stretch reflex (86 %), including increases (80 %) and decreases (6 %); nausea (44 %); tremor (25 %); and dysmetria (16 %) (inability to properly direct or limit motions). The temporary increases in blood pressure caused by the drug can be a risk factor for users with pre-existing hypertension. These qualitative somatic effects caused by psilocybin have been corroborated by several early clinical studies. A 2005 magazine survey of club goers in the UK found that nausea or vomiting was experienced by over a quarter of those who had used hallucinogenic mushrooms in the last year, although this effect is caused by the mushroom rather than psilocybin itself. In one study, administration of gradually increasing dosages of psilocybin daily for 21 days had no measurable effect on electrolyte levels, blood sugar levels, or liver toxicity tests.
