Erectile dysfunction and heart disease are very serious medical conditions that requires prompt treatment. In addition to being a symptom of heart disease; ED is linked to many other physical and psychological problems. Men with ED can be withdrawn from their partner and even avoid romantic relationships. It may be difficult for men with erectile dysfunction to reproduce and can lead to low self-esteem, depression and poor work performance.  Frequent medical check ups for patients with erectile dysfunction and high blood pressure is recommended.
Towards this direction, several sufficiently powered studies have demonstrated a higher incidence of erectile dysfunction in patients with coronary artery disease, either asymptomatic or overt. At the same time, patients with erectile dysfunction are more prone to have established coronary artery stenosis of more than 50% and consequently evident CV disease[75]. This is in conformity with the “artery size hypothesis” according to which smaller arteries (e.g., penile arteries) are the first to undergo a vascular lesion prior to the larger ones (e.g., coronary arteries). Moreover, in such patients erectile dysfunction is connected to the number of occluded vessels and more interestingly occurs over three years before coronary artery disease becomes apparent[76-80].
Not enough info for you? No problem. Nerd out on erectile dysfunction with these studies and research from the most trusted sources on the interwebs. If you have any questions or you think we missed something important, leave a comment or book a consultation with me or one of these trained professionals and we’ll get you on the way to a healthier manhood.
Since their introduction in the therapeutic field, more than a decade ago, PDE-5 inhibitors have revolutionized the treatment of sexual dysfunction. By blocking the activity of PDE-5 isoenzyme, localized throughout the smooth muscle cells of the vasculature (genital vessels included), PDE-5 inhibitors increase the levels of cyclic guanosine monophosphate thus exerting vasodilating properties and facilitating penile erection[40-42]. Due to these properties, sildenafil was the first drug of its class to receive wide acceptance. Its short half-life, food interactions and the associated visual disturbances however, paved the way for the development of newer PDE-5 inhibitors. As such vardenafil with its more rapid onset of action, and tadalafil with its longer half-life and the lack of food interactions or side effects, have offered significant alternatives to sildenafil[43-50].
There’s some evidence that bark from the yohimbe tree can help with ED. The bark contains a substance called yohimbine. It’s been traditionally used in Africa as an aphrodisiac. Today, a pharmaceutical form of yohimbine (called yohimbine hydrochloride) is being studied to treat erectile dysfunction in men. However, it can cause severe side effects, including high blood pressure, tremors, and anxiety.
Furthermore, if feelings of sadness, bloating, or weight gain are prominent, it may be beneficial to measure a form of estrogen called estradiol. This form of estrogen can be elevated in men, particularly in those who are overweight, and may trigger these abnormal responses, increasing the risk of heart disease. Estradiol levels above 30 pg/mL are generally considered abnormal. Weight loss can help correct elevated estradiol, as can prescription “aromatase inhibitors,” such as Arimidex®. In addition, a nutritional supplement called chrysin has been shown in the laboratory to inhibit the aromatase enzyme that is responsible for converting testosterone to estradiol.24 You should consult your doctor to determine if this supplement may be helpful for you.

In the vessels that supply the heart, healthy arteries enlarge in diameter up to 50% during exercise when sufficient nitric oxide is present. Because of its brief half-life, a continual supply of nitric oxide is required for optimal effect. If the supply of nitric oxide is inadequate, endothelial dysfunction—a core factor in heart disease—is made worse. Endothelial dysfunction can trigger the growth of coronary plaque.8
• Blood Vessels: Diabetes damages blood vessels, especially the smallest blood vessels such as those in the penis. Diabetes can also cause heart disease and other circulatory problems. Proper blood flow is absolutely crucial to achieving erection. “Erection is a hydraulic phenomenon that occurs involuntarily,” says Arturo Rolla, MD, of Harvard University School of Medicine. “Nobody can will an erection!” Anything that limits or impairs blood flow can interfere with the ability to achieve an erection, no matter how strong one’s sexual desire.
Logically, ED secondary to testosterone deficiency should be treated by testosterone replacement. Testosterone levels in men decrease with age.4 Both epidemiological and observational studies have demonstrated that reduced testosterone is associated with increased cardiovascular risk. One meta-analysis showed lower testosterone and higher 17β oestradiol as significant risk predictors despite adjustment for age and body mass index.4 Patients with coronary artery disease (CAD) have been found to have lower testosterone levels than controls, and there is inverse correlation between testosterone and the incidence of major cardiovascular disease (CVD).4 A significant negative correlation has been reported between total testosterone levels and Framingham risk score.4 However, it has been pointed out that ‘It is unclear if this is a causal association or due to low testosterone being a biomarker of poor health’.4 Testosterone replacement as a treatment for …
Abstract | Full Text | Full Text PDF | PubMed | Scopus (25) | Google ScholarSee all References Hemodynamic stress also may cause rupture of a vulnerable atherosclerotic plaque resulting in angina, myocardial infarction, or sudden cardiac death.80x80Muller, JE. Triggering of cardiac events by sexual activity: findings from a case-crossover analysis. Am J Cardiol. 2000; 86: 14F–18F
Mancia G,  Laurent S,  Agabiti-Rosei E,  Ambrosioni E,  Burnier M,  Caulfield MJ,  Cifkova R,  Clément D,  Coca A,  Dominiczak A,  Erdine S,  Fagard R,  Farsang C,  Grassi G,  Haller H,  Heagerty A,  Kjeldsen SE,  Kiowski W,  Mallion JM,  Manolis A,  Narkiewicz K,  Nilsson P,  Olsen MH,  Rahn KH,  Redon J,  Rodicio J,  Ruilope L,  Schmieder RE,  Struijker-Boudier HA,  van Zwieten PA,  Viigimaa M,  Zanchetti A. European Society of HypertensionReappraisal of European guidelines on hypertension management: a European Society of Hypertension Task Force document, J Hypertens , 2009, vol. 27 (pg. 2121-2158)https://doi.org/10.1097/HJH.0b013e328333146d

Erectile dysfunction (ED) is highly prevalent affecting at least 50 % of men with diabetes mellitus (DM). DM may cause ED through a number of pathophysiological pathways. These include neuropathy, endothelial dysfunction, cavernosal smooth muscle structural/functional changes, and hormonal changes. Lifestyle changes, diabetes control, and treatment of hypogonadism are important as the first step in ED management since there is no curative treatment for ED. Phosphodiesterase type 5 inhibitors (PDE5i) are the first-line treatment option. Intracavernous administration of vasoactive drugs is commonly used as a second-line medical treatment when PDE5i have failed. Alprostadil is the most widely used drug in this second-line setting. The combination of papaverine, phentolamine, and alprostadil represents the most efficacious intracavernous pharmacologic treatment option that may save non-responders to alprostadil. Penile prosthesis implantation can be considered in treatment refractory cases, with excellent functional and safety results in the properly informed patients.
Crossref | PubMed | Scopus (171) | Google ScholarSee all References Incidence increased notably with age in this patient cohort: only 1.1% of diabetic men aged 21 to 30 years had ED compared with 47.1% of all diabetic patients older than 43 years. Diabetic patients often have other cardiovascular risk factors that may play a role in the development of ED. However, in an analysis of the PBI in 441 patients with ED and various cardiovascular risk factors (diabetes mellitus, hypertension, hyperlipidemia, tobacco use), diabetes was the only risk factor that was significantly and independently associated with a decrease in the PBI.7x7Virag, R, Bouilly, P, and Frydman, D. Is impotence an arterial disorder? a study of arterial risk factors in 440 impotent men. Lancet. 1985; 1: 181–184

Abstract | Full Text PDF | PubMed | Scopus (3562) | Google ScholarSee all References The 9-year follow-up MMAS study also found that self-reported increased cholesterol and unsaturated fat intake correlated positively with the development of ED.5x5Feldman, HA, Johannes, CB, Derby, CA et al. Erectile dysfunction and coronary risk factors: prospective results from the Massachusetts Male Aging Study. Prev Med. 2000; 30: 328–338


De Berardis et al.6 assessed general HRQOL in 1,460 men with type 2 diabetes in Italy. Within the cohort, 615 men reported that they never experienced ED, 346 stated that they occasionally had ED, and 449 stated that they frequently had ED. They then compared general HRQOL among these three groups. In the univariate analysis, they found that degree of ED negatively correlated with general HRQOL scores in all eight domains of the Short Form 36 (SF-36) health survey questionnaire. In the multivariate analysis, ED was not independently associated with physical function, bodily pain, or role limitations due to physical problem scores but was independently associated with general HRQOL outcomes in the domains of general health (P = 0.004), role limitations due to emotional problems (P = 0.001), vitality (P = 0.001), social functioning (P = 0.01), and overall mental health (P = 0.002). Another study examining the effect of ED on quality of life in hemodialysis patients, more than half of whom had diabetes, also noted an independent, negative effect of ED on the emotional domains of general HRQOL.39


Since erectile dysfunction presents such an intimate relationship with CV parameters, it is easily deducted that it could constitute a powerful tool for detecting asymptomatic CV disease. Consequently, recognition of sexual dysfunction in a hypertensive individual should prompt further diagnostic procedures and therapeutic interventions in order to disclose its silent cardiovascular risk and improve patient’s quality of life and life expectancy.
Sexual intercourse is an infrequent cause of myocardial infarction. In a study of 1774 patients after myocardial infarction, only 1.5% of these events occurred within 2 hours of sexual intercourse, and sexual activity was considered a direct contributing factor in 0.9%.8x8Muller, JE, Mittleman, A, Maclure, M, Sherwood, JB, Tofler, GH, and Determinants of Myocardial Infarction Onset Study Investigators. Triggering myocardial infarction by sexual activity: low absolute risk and prevention by regular physical exertion. JAMA. 1996; 275: 1405–1409
Having your current medication checked – if you are taking medication already, it could be that your erection problems are a side effect. Have a doctor check whether this is the cause of your problems and if it is, you might be able to switch medications and then find that your erectile dysfunction goes away completely – or at least improves. Medications that can cause erection problems include:
ED almost always has an organic or mixed etiology in diabetic men. This often results in diabetic men reporting more severe ED when they present for treatment of this condition. It is not surprising, therefore, to learn that diabetic men's responses to standard therapy for ED differ from those of the general population of men with ED.38 We, therefore, will now briefly review the literature regarding effectiveness of various ED therapies specifically in diabetic men.
Poor sleep patterns can be a contributing factor for erectile dysfunction, Mucher says. One review published in the journal Brain Research emphasized the intricate relationship between the level of sex hormones like testosterone, sexual function, and sleep, noting that testosterone levels increase with improved sleep, and lower levels are associated with sexual dysfunction. Hormone secretion is controlled by the body’s internal clock, and sleep patterns likely help the body determine when to release certain hormones. 
Abstract | Full Text | Full Text PDF | PubMed | Scopus (95) | Google ScholarSee all References Phase 2 and 3 trials reported minimal associated cardiac adverse effects, which occurred in 3% of patients taking sildenafil and in 3.5% of patients receiving placebos.10x10Kloner, RA and Zusman, RM. Cardiovascular effects of sildenafil citrate and recommendations for its use. Am J Cardiol. 1999; 84: 11N–17N

The medicine causes blood vessels to expand, increasing blood flow in the body and to the penis, thus helping patients to get an erection. Invasive surgeries that involve rods and balloons are also available to patients suffering from ED. While these treatments often come with potential side effects, discomfort and a financial burden, some ED patients may see success with them.


Core tip: The prevalence of erectile dysfunction is approximately 2-fold higher in hypertensive patients compared to normotensive individuals. However, erectile dysfunction remains under-reported, under-recognized, and under-treated in hypertensive patients. Lifestyle modification should be the mainstay of treating erectile dysfunction in patients with untreated hypertension. Switching antihypertensive therapy should be considered in treated hypertensive patients, unless administered drugs are absolutely indicated for the individual patient. Otherwise, phosphodiesterase-5 inhibitors should be used, since they are both effective and safe in hypertensive patients. Finally, erectile dysfunction offers the opportunity to recognize asymptomatic cardiovascular disease with obvious benefits for cardiovascular event prevention.
** Indeterminate risk patients include diabetics, those with mild or moderate stable angina pectoris, past myocardial infarction (2-8 wks) without intervention awaiting exercise electrocardiography, congestive heart failure (NYHA class III), and noncardiac sequelae of atherosclerotic disease (eg, peripheral artery disease and a history of stroke or transient ischemic attack); this patient with ED may require assessment for additional vascular disease using carotid intima-media thickness or ankle-brachial index and subsequent reclassification to low or high risk.

Get your diabetes under control. According to Dr. Nehra, the most important number you need to stay on top of is your A1C, which is a blood test that lets you know how well your blood sugar has been controlled for the past few months. Lifestyle changes can help and so can medications. Diabetes medications do not add to your risk for erectile dysfunction, says Nehra.


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This form of therapy has a response rate of well over 70%. The sympathetic nervous system normally maintains the penis in a flaccid or non-erect state. All of the vasoactive drugs, when injected into the corpora cavernosae, inhibit or override sympathetic inhibition to encourage relaxation of the smooth muscle trabeculae. The rush of blood engorges the penile corpora cavernosae sinusoidal spaces and creates an erection.

Ischaemic heart disease (IHD), also known as coronary artery disease (CAD), is a predominant manifestation of cardiovascular disease (CVD). CVD is the leading cause of morbidity and mortality, accounting for 17.3 million deaths globally every year; this figure is expected to grow to 23.6 million by the year 2030. Eighty per cent of these deaths occur in lower- and middle-income countries.5 ED and IHD are highly prevalent and occur concomitantly because they share the same risk factors, including diabetes, hypertension, hyperlipidaemia, obesity and smoking.
Smoking is an independent risk factor for ED. Tobacco smoking causes direct toxicity to endothelial cells, including decreased eNOS activity, increased adhesion expression and impaired regulation of thrombotic factors.6 A meta-analysis of 19 studies by Tengs and Osgood suggested that 40 % of the impotent men studied were current smokers compared with 28 % who had never smoked.49
*** High-risk patients include those with unstable or refractory angina pectoris, uncontrolled hypertension, congestive heart failure (NYHA class IV), recent myocardial infarction without intervention (<2 weeks), high-risk arrhythmia (exercise-induced ventricular tachycardia, implanted internal cardioverter defibrillator with frequent shocks, and poorly controlled atrial fibrillation), obstructive hypertrophic cardiomyopathy with severe symptoms, and moderate to severe valve disease, particularly aortic stenosis.
Now that we better appreciate the complex sequence of events necessary for erections to occur, it’s no surprise that testosterone alone yields less than perfect results. Erectile dysfunction represents more than just low testosterone, which is just one facet of the spectrum of dysfunctional phenomena that cause sexual dysfunction. Nonetheless, when testosterone is combined with popular drugs like Viagra®, success is enhanced to an even greater degree—orgasmic function improves, along with erectile capacity and libido.20 Testosterone also activates penile nitric oxide; ultrasound studies have demonstrated a 27% increase in arterial blood flow into the penis with testosterone supplementation.23
Crossref | PubMed | Google ScholarSee all References In the general population, the estimated relative risk of experiencing a myocardial infarction within 2 hours after sexual intercourse is approximately 2.5 times higher than the baseline infarction risk of that individual, which itself is extremely low8x8Muller, JE, Mittleman, A, Maclure, M, Sherwood, JB, Tofler, GH, and Determinants of Myocardial Infarction Onset Study Investigators. Triggering myocardial infarction by sexual activity: low absolute risk and prevention by regular physical exertion. JAMA. 1996; 275: 1405–1409
The medications used to treat high blood pressure do not take into account the symptoms of erectile dysfunction, as their intention is to lower the blood pressure to a more manageable state, reducing the stress put on blood vessels. High blood pressure and ED are seen as separate entities, with the former taking priority for pharmaceutical treatment. This means that the medications used might do nothing to cure erectile dysfunction and may, in fact, prolong it. Medications that lower blood pressure might actually cause a low blood pressure state in the groin area and the arteries supplying the penis, making it near impossible to achieve an erection. The following are examples of such medications:

Medications used in the treatment of cardiovascular disease, especially antihypertensive medications, have been implicated frequently in the development of sexual dysfunction. A study of 5485 patients in the Hypertension Detection and Follow-up Program found that, during a 5-year period, 8.3% of male hypertensive patients stopped taking their antihypertensive medications secondary to sexual adverse effects.35x35Curb, JD, Borhani, NO, Blaszkowski, TP, Zimbaldi, N, Fotiu, S, and Williams, W. Long-term surveillance for adverse effects of antihypertensive drugs. JAMA. 1985; 253: 3263–3268
This content is strictly the opinion of Dr. Josh Axe and is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of medical advice or treatment from a personal physician. All readers/viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. Neither Dr. Axe nor the publisher of this content takes responsibility for possible health consequences of any person or persons reading or following the information in this educational content. All viewers of this content, especially those taking prescription or over-the-counter medications, should consult their physicians before beginning any nutrition, supplement or lifestyle program.
In TCM, the meridian system is thought to represent a path through which the life energy qi flows and as discussed in earlier section, the “Jing” (kidney) qi plays an important role in penile erection. Acupuncture helps to correct the imbalances to relieve physical symptoms by stimulating various meridian points. The Shensu (BL23), Zusanli (ST36) and Neiguan (PC6) points represents important acupoints for penis stimulation and thus has a positive homeostatic effect on the autonomic nervous system, and potentially modulate NO release (55,56). While some studies have showed up to a third of patients reported improvement in penile erection and sexual activity, systematic review showed insufficient data to conclude that acupuncture is an effective intervention for treating ED (56,57). Therefore, further scientific research is required to investigate whether there are specific benefits of acupuncture for men with ED before acupuncture can be accepted as evidence-based practice.
Erectile dysfunction is an accurate predictor of heart attacks and strokes in the future. Psychogenic components play a role in erectile dysfunction, but the most common and primary cause in most men is organic vascular insufficiency, meaning not enough blood gets to the penis. Erectile dysfunction usually occurs one to five years before a male manifests overt signs of cardiovascular disease. The first sign may be death.
Abstract | Full Text | Full Text PDF | PubMed | Scopus (66) | Google ScholarSee all References However, α-blockers are a well-known cause of retrograde ejaculation secondary to a reversible relaxation of bladder neck smooth muscle.50x50Meinhardt, W, Kropman, RF, Vermeij, P, Nijeholt, AA, and Zwartendijk, J. The influence of medication on erectile function. Int J Impot Res. 1997; 9: 17–26
Surgical implantation of a penile prosthesis, either the inflatable (2- and 3-piece) or the malleable device, is a feasible technique that offers a third-line treatment and a more permanent solution to the problem of erectile dysfunction. Interestingly, prosthesis implantation receives a significantly high satisfaction rate as evidenced by the proportionate scores in sexual satisfaction scales. Mechanical failure and infection are the two major disadvantages of those prosthetic implants however, their great efficacy, safety and satisfaction rate in general render them an attractive solution when conservative treatment fails[70-74].
PubMed | Google ScholarSee all References Diabetes was found to play a major role in vasculogenic impotence in a study of 265 patients with ED who underwent color duplex ultrasonography of the cavernosal arteries after intracavernosal injection of prostaglandin E1.13x13Chung, WS, Shim, BS, and Park, YY. Hemodynamic insult by vascular risk factors and pharmacologic erection in men with erectile dysfunction: Doppler sonography study. World J Urol. 2000; 18: 427–430

The same device is considered a vacuum erectile device (VED), when it is used to increase inflow of the blood to the penis without a constriction band. Regular use of VED in post-prostatectomy patient increases penile oxygenation and is accepted as a valid option in penile rehabilitation. Recent study reported transient increase in oxygenation to the glans penis and corporal bodies were detected by oximetry after VED was applied, providing proof for possible role for VED to counter the early penile hypoxia, cavernosal fibrosis and long-term ED after radical prostatectomy (9).


A disruption anywhere along the complex chain of events will impair the capacity to have an erection. Any man who has experienced the frustration of male impotence knows that the consequences extend beyond physical dissatisfaction to anxiety, tension, and embarrassment. A common reason for failure of the erectile apparatus is disruption of the path leading to nitric oxide production and blood flow control.
If you bike a lot and have a very narrow saddle on your bicycle, consider switching to a "no-nose seat" which is wider at the back than a conventional saddle, allowing more of your weight to be distributed to the sitting bones. Make sure the seat is level or angled slightly downward and at a height that allows your knee to be just slightly bent at the bottom of the pedal cycle. Raising the handlebars on your bike so that you're sitting upright may also help.
For over 25 years, Dr. Fuhrman has shown that it is possible to achieve sustainable weight loss and reverse heart disease, diabetes and many other illnesses using smart nutrition. In his medical practice, and through his books and PBS television specials, he continues to bring this life-saving message to hundreds of thousands of people around the world.
Recent revised labeling for sildenafil states that there is a lack of controlled data for its use in patients with resting hypotension (<90/50 mm Hg) or hypertension (>170/110 mm Hg); a history of myocardial infarction, cerebrovascular accident, or life-threatening arrhythmia within the past 6 months; coronary artery disease or cardiac failure causing unstable angina; or retinitis pigmentosa and possible genetic disorders of retinal PDEs.10x10Kloner, RA and Zusman, RM. Cardiovascular effects of sildenafil citrate and recommendations for its use. Am J Cardiol. 1999; 84: 11N–17N
Overall, sildenafil appears to be relatively safe and effective for treatment of ED in men with stable cardiovascular disease who are not taking NO-donor medications. In a study of 105 men with ED and known or likely coronary artery disease, patients underwent symptom-limited supine bicycle echocardiography 2 times after receiving either sildenafil or placebo.63x63Arruda-Olson, AM, Mahoney, DW, Nehra, A, Leckel, M, and Pellikka, PA. Cardiovascular effects of sildenafil during exercise in men with known or probable coronary artery disease: a randomized crossover trial. JAMA. 2002; 287: 719–725

Table 1 offers elements for distinction between organic and psychogenic disease.7 Of note is that in cases of organic origin, a psychogenic component may co-exist. The most common organic aetiology of ED is vasculogenic (see below ‘ED and CAD: common pathophysiology’).2,3 Co-existence of vascular disease, advancing age, and the presence of CVD risk factors and metabolic disorders increase the likelihood that ED is of vasculogenic aetiology.
Diabetes, high blood pressure (hypertension), elevations in blood lipids or cholesterol are considered blood vessel problems and have all been associated with Erectile Dysfunction. The blood vessel abnormalities caused by these diseases affect vessels throughout the body and often produce other symptoms of vascular diseases. Diabetics and patients with hypertension frequently have heart disease. These conditions typically interfere with the ability of the penile vessels to work properly and ultimately cause ED.

Smoking is an independent risk factor for ED. Tobacco smoking causes direct toxicity to endothelial cells, including decreased eNOS activity, increased adhesion expression and impaired regulation of thrombotic factors.6 A meta-analysis of 19 studies by Tengs and Osgood suggested that 40 % of the impotent men studied were current smokers compared with 28 % who had never smoked.49
Andersson said the results came as a surprise because erectile dysfunction is associated with an increased risk of heart disease in otherwise healthy men. However, previous studies have associated the use of PDE5 inhibitors with a decreased blood pressure in the left ventricle, which reduces the amount of work required to pump blood and therefore could help explain why the drugs might benefit people with heart failure. PDE5 inhibitors were initially developed to treat angina, a type of chest pain that results from constricted arteries.
An equally valuable observation though, is the fact that sexual dysfunction could indeed indicate asymptomatic CV disease. A solid amount of evidence accumulated over the last years has pointed out towards that trend moving, hesitatingly though, sexual dysfunction in the surface of scientific interest. As such, commonly under-reported, under-recognized and under-treated, sexual dysfunction could indeed play its role in cardiovascular risk assessment and stratification.
Physical and sexual activity can trigger acute cardiac events. In a recent meta-analysis, a significant association between acute cardiac events and episodic physical (relative risk 3.45 for myocardial infarction and 4.98 for sudden cardiac death) and sexual activity (relative risk 2.7 for myocardial infarction) was demonstrated.32 This association was attenuated among individuals with high levels of habitual physical activity (for every additional time per week the relative risk for myocardial infarction decreased by ∼45%, and the relative risk for sudden cardiac death decreased by 30%). The physical demands of sexual activity have been identified as follows. Studies conducted primarily in young married men showed that sexual activity with a person's usual partner is comparable with mild-to-moderate physical activity in the range of 3–4 metabolic equivalents of the task (METS).30,33 The heart rate rarely exceeds 130 b.p.m. and systolic blood pressure rarely exceeds 170 mmHg in normotensive individuals. Accordingly, demands during sexual activity correspond to walking 1.5 km (or 1 mile) on the flat in 20 min or briskly climbing two flights of stairs in 10 s. Generalization, however, may not characterize all individuals (especially those who are older, are less physically fit, or have CVD) or sexual activity circumstances (e.g. extramarital, unfamiliar setting, excessive food and alcohol consumption). Therefore, completing 4 min of the standard Bruce treadmill protocol (5–6 METS) without symptoms, ST segment changes, arrhythmias, or a fall in systolic BP identifies the safety of sexual activity.30,33
Relaxation of erectile tissue requires nitric oxide from nonadrenergic-noncholinergic neurons and the endothelium.21 Penile tissue from diabetic men with ED demonstrates impaired neurogenic and endothelium-mediated relaxation of smooth muscle,22 increased accumulation of advanced glycation end products (AGEs),23 and upregulation arginase, a competitor with nitric oxide synthase for its substrate L-arginine.24 Normal responses to direct smooth muscle relaxants in most of these studies implies that the impairments are due to decreased synthesis, release, or activity of nitric oxide. The fundamental mechanisms mediating these changes are thought to be the same as for other diabetic complications: increased polyol pathway flux, intracellular accumulation of AGEs, activation of protein kinase C, and increased flux through the hexosamine pathway.25
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