###Human: Can low testosterone levels cause fatigue and increased heart rate? ###Assistant: Hello. As your BMI (body mass index) is 34, in obesity, the decreased levels of testosterone-binding protein cause a decrease in the total testosterone levels, but not the normal free level. Before we evaluate you for low testosterone, we need to confirm it by doing free testosterone levels. If free is also low, then we need to find the cause, for that, we need FSH (follicle-stimulating hormone) and LH (luteinizing hormone) level. So, you first get free testosterone levels done. Also, any anxiety, depression, or any psychological issues can cause loss of libido. You can visit an endocrinologist for the same. Secondly, regarding your heart rate, it is certainly not related to testosterone. But it can be related to anxiety, alcohol, and heart. There are two possibilities, one is anxiety related and secondly due to heart arrhythmia. Many individuals who drink, tend to have a weakening of the heart and atrial fibrillation, in which heart beats irregularly and fast, especially after drinks. Hope this helps you. Get back if you have any further doubts. For more information consult an internal medicine physician online -->