Which symptom can be a result of excessive anticholinergic activity?

Excessive anticholinergic activity can lead to tachycardia, which is an increased heart rate. Anticholinergics work by blocking the action of acetylcholine, a neurotransmitter involved in the parasympathetic nervous system. Normally, acetylcholine promotes a "rest and digest" response, including actions that slow the heart rate. When anticholinergic agents excessively inhibit this activity, the sympathetic nervous system's influence becomes more pronounced, resulting in an increase in heart rate.

In contrast, bradycardia, which is a slower heart rate, occurs with underactivity or blockage of the sympathetic nervous system or with certain drugs that enhance parasympathetic activity. Hypersalivation is the increased production of saliva typically due to stimulation of the salivary glands by the parasympathetic nervous system, which would actually be inhibited by anticholinergic drugs. Urinary incontinence is associated with the inability to control urination, generally seen with an underactive bladder rather than with the effects of anticholinergic activity, which can actually lead to urinary retention since it inhibits bladder contractions. Therefore, tachycardia is the symptom specifically linked to excessive anticholinergic activity.