"The physiological effects of this powerful drug have been well documented. These effects can be grouped into five general areas of action: LSD works on the sympathetic nervous system (which is involved in regulation of heart muscle, smooth muscle and glandular organs in a response to stressful situations); the motor system (which is involved in carrying out limb movements); the affective states; thought processes; and it has profound effects upon the sensory and perceptual experience.

"LSD is a semisynthetic preparation originally derived from ergot, an extract of the fungus Claviceps purpurea, which grows as a parasite on rye wheat. The dosage that is required to produce a moderate effect in most subjects is 1 to 3mcg per kilogram of body mass, and the effects can last from seven to 10 hours (Bowman & Rand 1980).

"Stimulation of the sympathetic nervous system following LSD ingestion can lead to effects such as hypothermia with piloerection (hairs standing on end, such as can be found in reports of religious ecstasy), sweating, increased heart rate with palpitations, and elevation of blood pressure and blood glucose levels. These reactions of the autonomic nervous system are not as significant as other effects upon the body: action on the motor system can lead to increased activity of monosynaptic reflexes (such as the knee-jerk response), an increase in muscle tension, tremors, and muscular incoordination. This latter effect of muscular incoordination is also a symptom of religious ecstasy in many cultures, where the worshipper has such a profound feeling of love of God that he is said to be 'intoxicated by God.'"

Source

Goodman, Neil, "The Serotonergic System and Mysticism: Could LSD and the Nondrug-Induced Mystical Experience Share Common Neural Mechanisms?" Journal of Psychoactive Drugs (San Francisco, CA: Haight Ashbury Publications, July-September 2002), Vol. 34, No. 3, p. 266.