. 28 . Lifestyle changes for improving ED http://www.asiaandro.com; aja@sibs.ac.cn Do lifestyle changes work for improving erectile dysfunction? Kaya Horasanli, Ugur Boylu, Muammer Kendirci, Cengiz Miroglu The Second Urology Department, Sisli Etfal Training and Research Hospital, Sisli-34377, Istanbul, Turkey Abstract The main cause of erectile dysfunction (ED) is organic in nature, with vascular etiologies being the most common risk factors. Although there have been sufficient data on the relationship between ED and several well-recognized risk factors, including aging, coronary artery disease, atherosclerosis, diabetes mellitus, dyslipidemia, high blood pressure, and pelvic surgeries, little attention has been paid by the urologists to the role of lifestyle factors in ED. However, accumulating data from basic science and clinical studies have determined a link between the occurrence of ED and a number of lifestyle factors, such as smoking, obesity, alcohol consumption, and lack of physical activity. The application of findings from animal and human studies to the clinical practice regarding the modification of lifestyle factors could help improving ED as well as reducing the risks of developing cardiovascular diseases. This commu- nication addresses the impact of lifestyle factors on erectile function and the potential benefits of modifying these factors to improve ED in respect to the current evidence. (Asian J Androl 2008 Jan; 10: 28–35) Keywords: erectile dysfunction; lifestyle; smoking; obesity; alcohol; sedentary life . Review . DOI: 10.1111/j.1745-7262.2008.00363.x www.asiaandro.com ､ 2008, Asian Journal of Andrology, Shanghai Institute of Materia Medica, Chinese Academy of Sciences. All rights reserved. Correspondence to: Dr Muammer Kendirci, Sisli Etfal Egitim ve Arastirma Hastanesi, 2. Uroloji Klinigi, Sisli-34377, Istanbul, Turkey. Tel: +90-212-231-2209 ext. 1290 Fax: +90-212-233-9687 E-mail: mkendirci@superonline.com 1 Introduction Erectile function is a complex phenomenon regulated by neural, hormonal, vascular and structural factors. Penile erection is the end result of a chain of events that cause smooth muscle relaxation in the corpora cavernosa of the penis. Upon sexual stimulation, nitric oxide (NO), the key mediator for the initiation and maintenance of penile erection, is synthesized and released by the auto- nomic nerves and endothelium, serving the penile arteries and nerve terminals of the corpus cavernosum [1]. NO enters the cavernosal smooth muscle cell and activates soluble guanylate cyclase (sGC), which promotes the formation of cyclic guanosine monophosphate (cGMP). Through a cascade of events, cGMP reduces intracellular calcium levels, allowing for relaxation of smooth muscle cells of the vasculature. Good erectile function depends on a delicate homeostasis between vascular constricting and relaxing factors through a healthy endothelium. The vascular endothelium of the penis plays a pivotal role in modulating vascular tone and blood flow into the penis in response to humoral, neural, and mechanical stimuli. In endothelial dysfunction, the regulatory role of the endothelium is hindered, resulting in decreased respon- siveness to vasodilatory mediators and/or increased sensi- tivity to various vasoconstricting agents. Well-recognized disease states and vascular risk factors, such as diabetes mellitus, coronary artery disease, atherosclerosis, hypertension, and smoking, have long been known to impair penile endothelial function, resulting in a decrease in endothelial-dependent corpora cavernosal smooth muscle relaxation through decreased expression and ac- tivity of neuronal and endothelial NO synthase (nNOS and eNOS), impaired NO release, and/or increased de- struction or total loss of NO bioactivity in the penis [2]. Although the impact of abovementioned well-known risk factors and disease states on erectile function have been extensively elucidated, little attention has been paid by the sexual medicine specialists to the role of lifestyle factors in penile endothelial function and ED. As ED has a significant impact on quality-of-life by reducing self- esteem and confidence, and by affecting interpersonal relationships to the point of termination, all aspects of the contributing factors need to be evaluated. Recently