Researchers from University of British Columbia, University of Alberta and Mazankowski Alberta Heart Institute, Massachusetts General Hospital in Boston, and Brigham and Women's Hospital in Boston analyzed data from 4 previous studies in which patients were randomly assigned to receive either testosterone therapy or a placebo for a period of 12 to 52 weeks. Testosterone patches and injections were used to improve the breathing and exercise abilities of participants.
Among a total of 198 participants whose average age was 67, 84 percent were men. These participants were taking standard medical treatments for heart failure. Some of these participants had symptoms even after receiving standard therapies, and physically they could not walk, as far as or as much as, they could when they were healthy.
During a 6-minute walking test, participants who took testosterone therapy walked an average of 177 feet (54 meters) more than those who took placebo. For participants taking testosterone therapy, there was also an increase in VO2 max, which is the amount of oxygen used per minute of exercise. VO2 max is a general indicator of a person’s fitness level. Meanwhile, there were no adverse effects found on the heart.
According to researchers, testosterone did not affect the heart itself. Instead, it might target the peripheral tissues such as the skeletal muscles. The hormone has been shown to widen blood vessels, allowing more blood to reach peripheral tissues. It might also raise the levels of hemoglobin, which is a protein in red blood cells that transport oxygen.
While the majority of the participants were males, the results could also apply to women through much smaller doses of testosterone.
It seems that testosterone is a promising therapy, but it is not advisable to use testosterone therapies right away just based on their results. Researchers revealed that there was a small increase in levels of prostate-specific antigen (PSA) among men who took testosterone therapy in the study. High PSA levels indicate that there is a risk of prostate cancer. Previous studies did find a link between high doses of testosterone and increase cases of prostate cancer.
Hence, larger studies are required to confirm the findings and find out the best method of delivery and the appropriate doses, but more importantly, the long-term effects of testosterone therapy, especially their effect on prostate cancer.