<qa>  What is the effect of beta-blockers on the body?Studies have shown that beta-blockers such as atenolol when given in the perioperative period reduce morbidity and mortality. One study showed that atenolol given just during the surgery period, seemed to improve outcomes up to 2 years later. This is hard to explain since beta-blockers act on the body by blocking the effects of adrenalin and thereby lowering heart rate and blood pressure. 