Testosterone and the heart - the missing link?

Описание: Testosterone is the principal male sex hormone and we know that in general, as men get above the age of 40 testosterone levels start dropping. We also know that as men get above the age of 40, their overall cardiac risk and overall risk of mortality starts increasing. So it appears that overall cardiac risk starts going up around about the same time as testosterone levels start falling. What we still don't know is whether they are both simply a consequence of aging or whether in some way testosterone is protective for cardiac risk.

In this blog, i will review exactly what we know about testosterone and the heart so far.

Testosterone is produced in the male testes and about 98% binds to a carrier called SHBG (sex hormone binding globulin) and about 1-2% circulates unbound or 'free' The free testosterone is perhaps the most potent biological form.

Testosterone is responsible for development of primary and secondary sex characteristics and also increases both muscle mass and bone density.
When men become testosterone deficient, they often develop reduced libido, erectile dysfunction, reduced energy levels, bad mood and increased irritability. Overall sexuality, health status and quality of life all deteriorate.

The prevalence of testosterone in middle aged/older men is quoted in the literature as being anywhere between 2.1-12.8%.

Patients who are particularly vulnerable to being testosterone deficient include:

CHF
Type 2 diabetes
Obesity
COPD
HIV
Opioid users

Currently the way it is diagnosed is through an early morning blood test which measures total testosterone levels and if the level is less than 200 ng/mL then that is classed as testosterone deficiency. There is some controversy however over how good the assays are and especially if the value is at the lower levels of normal, what that means. Some scientists have suggested that maybe measuring the levels of free testosterone may be better but it is still unclear.