Ultimately low testosterone levels are linked to many cardiovascular issues and risks. According to the Harvard Medical School, hormone testosterone replacement therapy can help to widen coronary arteries. This can be helpful to men with angina or other heart-related issues. This also reduces their risk of heart attack or stroke. Testosterone naturally can cause red blood cell counts to rise, which is great for those with anemia. Also optimal levels of testosterone through hormone replacement therapy can decrease fat and increase strength and muscle size. In one study of men over 65, not only did these patients decrease their fat content, but had an increase in lean mass overall. These men were treated in a 3-year period. Optimal testosterone levels also lead to stronger bones. Ultimately as men age and/or levels drop, bone density does too. This can limit athletic performance and leaves these men at a risk for osteoporosis and weak bones. According to The Journal of Clinical Endocrinology & Metabolism, older men can increase their bone density with hormone replacement therapy sessions.