Events caused by sleep apnea and atrial fibrillation, two disorders that share many of the same risk factors and symptoms, can wake you up to a pounding heart. Unless you have an emotional condition, such as anxiety, your increased pulse rate may have these physical causes.

Sudden, extreme fatigue occurs for a variety of reasons. Common causes include infections, severe stress and new onset depression, among others.

Many medical conditions can cause both pain in the legs and fatigue, and determining the cause of these symptoms often requires a trip to the doctor. To make a diagnosis, your doctor needs a thorough understanding of your symptoms, including what brings them on, what improves them, and other symptoms you may have.

Sometimes, you just feel drained, tired and hungry. However, you must be able to tell when those feelings are just that, or something more serious that may affect your health. Understanding the basic symptoms and signs of fatigue and those of excessive hunger help you to listen to what your body is telling you.

Mono, which is more formally referred to as mononucleosis, is an infectious disease caused by exposure to the Epstein-Barr virus, or EBV.

Events caused by sleep apnea and atrial fibrillation, two disorders that share many of the same risk factors and symptoms, can wake you up to a pounding heart. Unless you have an emotional condition, such as anxiety, your increased pulse rate may have these physical causes.

Overtraining can affect anyone who exercises regularly, not just endurance athletes. Increasing the frequency, duration and intensity of your workout program too quickly can lead to this syndrome, which manifests in a myriad of ways.

A combination of sweating, chills, fatigue and nausea symptoms can signal a wide range of medical conditions, from a passing virus to more serious, potentially life-threatening diseases. Contact your physician if you are experiencing these symptoms.

Being tired and having lack of stamina and energy can be a healthy response to emotional or physical exhaustion. If you know what is causing you to feel worn out you may be able to fix the problem with a few simple tweaks to your daily habits.

Body aches and fatigue are common symptoms of a variety of illnesses and conditions. While both terms are somewhat vague, body ache usually refers to soreness in the muscles, while fatigue is another word for lack of energy or exhaustion.

Bloating is often described as a feeling of fullness or pressure in the abdomen that results in a physical swelling or distention of the abdomen. Occasional bloating in women is normal and usually occurs as a result of improper digestion of gas-forming foods or as a regular symptom of the reproductive cycle.

Whether it is spring or fall, if you suffer from allergies, you run the risk of becoming sick. For some sufferers, allergies cause nasal congestion, headache and cough. For others, if their bodies react strongly enough, their symptoms may include a low-grade fever and fatigue.