Testosterones are hormones that are found in humans, as well as other animals. It is the most common hormone in men, which helps with their growth, physical features and muscle mass. In men, the testicles are the primary producer of this hormone. Women also produce testosterone in their ovaries, however, the amount is much smaller. This is why testosterone is known as "male hormones" and increased levels of "male hormones" in women may lead to hormonal imbalance. The production of testosterone usually increases during puberty and dips after the age of 30. It is associated with sex drive and plays an important role in sperm production and affects bone and muscle mass, the way men store fat in their body and red blood cell production. It can also affect a man's mood. For the longest time, especially in the ancient texts, it was believed that testosterone is the reason why men have a shorter life span. In fact, a paper published by Kyung-Jin Min, Cheol-Koo Lee and Han-Nam Park in 2012, titled The Lifespan of Korean Eunuchs states that neutered animals and Korean eunuchs had longer life spans due to less production of testosterone. However, a recent study by a team at the University of Western Australia titled Associations of Testosterone and Related Hormones With All-Cause and Cardiovascular Mortality and Incident Cardiovascular Disease In Men, published in Annals of Internal Medicine, questions the old findings.New FindingsThe study followed men for five years and found that participants with the lowest testosterone levels were more likely to die. While the cause of death was not directly related to the hormone, upon deeper analysis, it was found that men who died were mostly experiencing some sort of heart disease. This is also the leading cause of death in men, globally. The interesting observation is that it could be linked to erectile dysfunction and the inability to get enough blood pumped to keep an erection firm enough for sex. This usually occurs earlier than the symptoms of heart diseases show up, and thus, it could act as an early warning sign of existing heart problems. How Was The Study Conducted?The researchers gathered 11 studies with 24,000 people to see how testosterone level had an influence men and their life span. The men from the selected studies previously had their total testosterone measured using mass spectrometry; followed for a minimum of 5 years. The researchers were able to gather data about baseline levels of various hormones, including total testosterone, sex hormone-binding globulin, luteinizing hormone, dihydrotestosterone, and estradiol. When the researchers looked for a relationship between these levels and the participant's risk for cardiovascular diseases or deaths from any cause, it was seen that men who had a low total testosterone, which is below 7.4 nmol/L had a greater risk of dying from any cause. It was also noticed that men with further lower levels of testosterone below 5.3 nmol/L had a higher risk of dying from cardiovascular diseases. How To Find If You Have Low Testosterone Levels?A simple blood test can tell you about your testosterone count. The testosterone level should be drawn mid-morning, that is when they are at their peak for the day. There are two types of numbers which will be shown in your report. Where 'Free testosterone' means that it is bio-available, that it can be easily put to use in your body, whereas 'Total testosterone' means that it is both free testosterone and that one that is bound to certain proteins in your blood and cannot be used immediately.