The Many Ways Excess Weight Can Negatively Affect Erectile Function

Obesity is blamed for health ailments aplenty, almost affecting every bodily system and function, including sexual function. While we tend to accept that obesity is a major contributor to erectile dysfunction (ED), why is it?

Excessive weight is a direct and indirect contributor to ED, explained Justin Houman, M.D., a urologist and men's sexual and reproductive health specialist at Tower Urology in Los Angeles. He delved into some statistics related to body mass index (BMI), a measure of body fat based on weight and height:

• Of men who have erectile dysfunction, 79 percent have a BMI of 25 or greater—25 marks the start of the overweight range.
• If your BMI is between 25 and 30, you have a 1.5-times increased risk of ED.
• If your BMI is 30 or greater, which is considered obese, you have three times the risk of experiencing ED.

To understand the link between obesity and ED, you need to know what causes an erection.

For people without ED issues, getting an erection seems simple, but Justin Dubin, M.D., a urology fellow specializing in male infertility and sexual medicine at Northwestern University, explained the five elements needed for a good erection:

1. Arousal
2. Hormones (specifically testosterone)
3. Good nerves in your penis
4. Good blood flow to your penis
5. Good state of mind (no significant anxiety, depression, etc.)

Not to scare, but if any of these elements fail, you may have an episode of ED.

"When a man is obese or overweight, he puts himself at increased risk for ED because obesity can compromise several of these things you need to have a good erection," Dubin said.

Extra weight is a factor in erectile function for several reasons.

1. Hormonal imbalance

"Obesity throws off the hormonal balance by leading to decreased testosterone levels and increased estrogen [estradiol] levels," Houman said. "And low testosterone is definitely a risk factor for erectile and sexual dysfunction."

A 2007 study published in the Journal of Clinical Endocrinology & Metabolism analyzed testosterone levels in 1,667 men ages 40 to 70. The study found that for each one-point increase in BMI, there was an associated 2 percent decrease in testosterone.

Dubin explained that obesity lowers testosterone levels in several ways, but one of the main ways is that the increased body fat (adipose tissue) converts testosterone to estrogen in men. Increased estrogen levels can lower testosterone production, resulting in obese men with below-normal testosterone levels and poor erectile function.

Testosterone is also closely linked to libido in men, so the lower levels of testosterone caused by obesity can lead to a reduction in sexual desire.

2. Blood vessel damage

Obesity is an independent risk factor for cardiovascular disease.

"When people think of cardiovascular disease, they only think about their heart, but, really, many times the first thing to be damaged are the smaller vessels, including those in the penis," Dubin said.

Obesity is associated with high blood pressure and high cholesterol, which can damage the inner lining of the blood vessels, Houman said. When the blood vessel lining is damaged, the penis does not get enough blood flow to produce and sustain an erection.

In fact, Dubin explained erectile dysfunction is considered the "canary in the coal mine" for heart disease, because damage to the small arteries that prevents you from getting an erection is also a warning sign for future potential damage to the larger arteries in your heart.

3. Diabetes

As well as being a risk factor for cardiovascular disease, obesity is a known risk factor for diabetes, too. According to Dubin, diabetes slowly and silently affects many aspects of your body until you're eventually dealing with the repercussions of poorly controlled sugars. In many cases, your ability to get a satisfactory erection is one of the casualties.

"Diabetes is called 'the silent killer' for a reason: These issues don't happen overnight," Dubin said. "Most people are familiar with how diabetes can damage your eyes, hands and feet. This is because diabetes causes injury to both the blood vessels and nerves around the body. And just like injuries from cardiovascular disease, usually the smaller arteries and nerves, aka the ones in the penis, are often the first to go."

Diabetes is a major cause of ED because if your nerves don't work properly due to poorly controlled sugars, you won't be able to get a good erection.

4. Physical inactivity

Carrying extra weight may discourage an individual from engaging in physical activity, and, as we know, a sedentary lifestyle is not good for overall health. Some of the benefits of physical activity are:

• Increased testosterone levels
• Decreased stress and anxiety
• Improved body image
• Increased nitric oxide synthase, which helps protect your vascular system, dilate blood vessels and increase blood flow
• Strengthened endothelial function

If you're wondering about the last one, the endothelium is a thin membrane that lines the inside of blood vessels. It needs to function correctly so the body's tissues and organs can function normally.

When you're physically inactive, you miss out on all these positives that can help protect you from developing ED.

"Anything that negatively impacts your overall health, like obesity, will negatively impact your erectile and sexual function," Houman said.