A Lack of stamina is one of the most important issues for a man. It can negatively affect his relationships and self-confidence. It's not uncommon for a man to be depressed or moody, which make it all the more frustrating. There are also treatment options for these conditions, including prescription inhalers and natural remedies. A Lack of Stamina Causes & Solutions Listed Below A Lack of stamina can be a sign of an underlying medical condition. Your doctor should be able to identify the source of your fatigue, as well as help you find the best treatment. Generally, a Lack of stamina is the result of a lack of oxygen to the brain. If you're experiencing chronic fatigue, you might need to seek treatment for this problem. Your doctor can change the dosage of your medication.