Testosterone and its Role in Cardiovascular Protection

Testosterone protects against heart attacks and may even help reverse atherosclerosis in men (Zmuda, et al., 1997).  Low testosterone is associated with and contributes to metabolic syndrome, atherosclerosis, heart attack and stroke (Haffner, Karhapaa, Mykkanen, & Laakso, 1994; Khaw, et al., 2007; Oh, Barrett-Connor, Wedick, & Wingard, 2002; van den Beld, et al., 2003). Metabolic syndrome and diabetes are bad things to have if you’re trying to avoid a heart attack. If “your gut is larger than your butt” you probably have metabolic syndrome.

The benefits of healthy levels of testosterone in men include improved ejection fraction (a measure of the heart’s ability to pump blood to the rest of the body), increased muscle mass, decreased fat mass, improved sex drive, improved mood and improved bone density. High naturally occurring levels of testosterone in men are associated with low mortality from all causes, cardiovascular disease, and cancer (Khaw, et al., 2007).

Low testosterone is strongly associated with atherosclerosis but exactly how testosterone replacement therapy can slow down or reverse atherosclerosis is not completely understood yet. Lower levels of testosterone are associated with increased CIMT particularly in men with type II diabetes (De Pergola, et al., 2003). Remember that CIMT is a measure of carotid artery wall thickness and is a imaging toll that can detect the earliest stages of atherosclerosis.

Just how may correcting low testosterone play a role in reversing heart disease? 
1) Testosterone may be beneficial as a treatment for CAD because testosterone can improve conditions at contribute to heart disease such as diabetes, obesity, hypercholesterolemia and hypertriglyceridemia. 
2) Testosterone has been shown to dilate the arteries, improve circulation, and lower blood pressure in most studies (Dubey, Oparil, Imthurn, & Jackson, 2002).  Because some people get an increase in blood pressure on testosterone therapy it is very important to monitor blood pressure.
3) Testosterone receptors have been found within human arteries, including aortic, coronary, pulmonary, and carotid arteries, providing evidence that it can affect the arterial wall (Muller, et al., 2004).
4) Testosterone can lower LDL, triglycerides and lip (a)
5) Testosterone activates nitric oxide synthase and thus increases nitric oxide dependent vasodilatation (Jones, Hugh Jones, & Channer, 2004).
6) Testosterone gets converted into estrogen via the aromatase enzyme and normal levels of estrogen may have a beneficial impact on the arterial wall in men.

Prostate cancer and testosterone: Concern about the risk of prostate cancer is still the primary reason many practitioners get nervous about prescribing testosterone. Though existing prostate cancer is clearly a contraindication for testosterone therapy recent studies indicate no increased risk of prostate cancer with higher levels of testosterone. The problem with taking testosterone when you have prostate cancer may be due to the fact that testosterone converts to estrogen and estrogen is known to stimulate cancer growth. Testosterone replacement therapy may also stimulate your body’s production of growth hormone.  According to Dr. Mark A. Rubin, professor of pathology and laboratory medicine and vice chair for experimental pathology at Weill Cornell Medical College estrogen is a key player in about half of all prostate cancers, especially aggressive types.

A leading Urologist at Harvard Medical School, Dr. Abraham Morgentaler, also published a paper debunking the myth that testosterone causes prostate cancer (Morgentaler, 2006). He has even found that low levels of testosterone can be a risk factor for getting prostate cancer.
If either free or total testosterone is low I believe there is much more benefit to than risk when it comes to taking testosterone.  Testosterone is helpful in women for improving sex drive, for treating severe osteoporosis and for increasing muscle mass.  Testosterone should be kept in physiologic range. I recommend dosing testosterone to achieve levels in the upper third of the reference range for age.  If a weekly shot is used such as testosterone cypionate I like to check levels at 7 days which is the half -life. Typically 400-600 indicates adequate dosage. Other labs that should be monitored include DHT, estradiol, CBC, PSA and lipids.Negative cardiovascular side effects may occur however and include decreased HDL, increased blood pressure (increased fluid volume), and polycythemia.