THIS ARTICLE IS A DRAFT– PROCEED WITH CAUTION
Headaches always bring the underlying fear that something seriously wrong could be occurring with the brain, but fortunately most are not the immediate life-threatening type of headaches. A thunderclap headache is a sudden and severe headache that can be a sign of a medical emergency. The name “thunderclap” signifies the intensity and acuity of such headaches. In 25% of cases, a thunderclap headache is an indication of aneurysmal subarachnoid hemorrhage (SAH), which often leads to death or severe disability. Headaches which accompany SAH are frequently described as being the worst headache of one’s life, although other clinical presentations are possible. 
Major bones and regions of the skull.
While most headaches are not life-threatening, some headaches have serious, threatening causes so there is an important need for an accurate medical diagnosis. When serious conditions (brain tumors, cerebral aneurysms, encephalitis, meningitis and head injury) are ruled out, the next step is to search for causes that may be related to nutrition, food additives and supplements, metabolism, exertion, environmental exposure, substance abuse, stress and tension, lack of sleep, hunger, high blood pressure, sinus infections, and posture and body mechanics.
Headaches have five general classifications, but many other categories exist and there is complexity involved because the classifications can crossover or contribute to each other and because decisions to change and refine the classifications occur as a result of increases in medical knowledge.
Traction headaches involve displacement or distention of pain-sensitive structures in the head caused by tumor, bleeding from stroke or head injury. These are rapidly expanding lesions, which produce traction on the pain-sensitive areas of the head. Headache is a frequent manifestation of increased intracranial pressure. If the tumor is slow growing, the headache is usually mild and transient. This headache is easily relieved by over-the-counter analgesics, and the patient will rarely visit an Emergency Room. Eventually, the headache may become progressive due to enlargement of the mass (tumor or abscess) and resultant surrounding cerebral edema. Increases in intracranial pressure, due to Valsalva maneuver (blowing out while holding your breath), exertion, or other physical maneuvers, may exacerbate the pain. Neurological signs and symptoms may occur in patients with a mass lesion, depending on which area of the brain is involved. Signs of increased blood pressure may also occur. CT Scanning, and possibly M.R.I., is indicated in those patients presenting with exertional aspects to their headaches. Other neurological signs, such as headache accompanied by fainting, should alert the emergency physician to the need for further testing and referral to a specialist. These serious medical conditions are controlled by surgery and/or drugs.
Inflammatory headaches involve meningitis, encephalitis, sinusitis, temporal arteritis and trigeminal neuralgia and are controlled with drugs or antibiotics.
Vascular headaches, such as a migraine, involves constriction followed by dilation of blood vessels in the head. Pain is on one or both sides of the head and is often associated with visual disturbances, sensitivity to light, nausea and other sensory disturbances, such as numbness or altered kinesthetic awareness. Vascular headaches can also result from high blood pressure. Cluster headaches are also classified as vascular headaches. These are controlled by drugs, nutritional changes and lifestyle changes.
Muscular/myogenic headaches appear to involve the tightening or tensing of facial and neck muscles; they may radiate to the forehead. Tension headache is the most common form of myogenic headache.
The exact cause of tension-type headaches (TTH) is still unknown. It is suggested that abnormalities in the peripheral and central nervous systems may be involved in the pathophysiology of TTH. It has long been believed that they are caused by muscle tension around the head and neck and the restriction of blood flow to those areas as a result, the cause of which is in often the presence of an unresolved subconscious emotional conflict and anxiety. One of the theories says that the main cause for tension type headaches and migraine is teeth clenching which causes a chronic contraction of the temporalis muscle. Although muscle tension may be involved, scientists now believe there is not one single cause for this type of headache. Another theory is that the pain may be caused by a malfunctioning pain filter which is located in the brain stem. The view is that the brain misinterprets information, for example from the temporal muscle or other muscles, and interprets this signal as pain. One of the main molecules which is probably involved is serotonin. Evidence for this theory comes from the fact that chronic tension-type headaches may be successfully treated with certain antidepressants such as amitriptyline. However, the analgesic effect of amitriptyline in chronic tension-type headache is not solely due to serotonin reuptake inhibition, and likely other mechanisms are involved. Recent studies of nitric oxide (NO) mechanisms suggest that NO may play a key role in the pathophysiology of Chronic TTH.[3]. The sensitization of pain pathways may be caused by or associated with activation of nitric oxide synthase (NOS) and the generation of NO. Patients with chronic tension-type headache have increased muscle and skin pain sensitivity, demonstrated by low mechanical, thermal and electrical pain thresholds. Hyperexcitability of central nociceptive neurons (in trigeminal spinal nucleus, thalamus, and cerebral cortex) is believed to be involved in the pathophysiology of chronic tension-type headache.[4] Recent evidence for generalized increased pain sensitivity or hyperalgesia in Chronic TTH strongly suggests that pain processing in the central nervous system is abnormal in this primary headache disorder. Moreover, a dysfunction in pain inhibitory systems may also play a role in the pathophysiology of chronic tension-type headache.[5] These are controlled by drugs, nutritional changes and lifestyle changes.
Cervicogenic headaches originate from disorders of the neck, including the anatomical structures innervated by the cervical roots C1–C3. Cervical headache is often precipitated by neck movement and/or sustained awkward head positioning. Headache is often accompanied by restricted cervical range of motion, ipsilateral neck, shoulder, or arm pain of a rather vague non-radicular nature or, occasionally, arm pain of a radicular nature. These are controlled by drugs, nutritional changes, physical therapy and lifestyle changes. A neck condition or related conditions could require surgery.
Non-Threatening Conditions
How your head feels is a good indicator of how well you are taking care of yourself. Are you getting enough sleep? Managing stress all right? Eating enough of the right foods? Staying away from toxins in food and the environment? When serious, life-threatening conditions are ruled out, the question becomes what factor or combination of factors is causing this pain and annoyance – and what lifestyle change can get rid of the problem?
Nutrition, Hunger, Food Additives and Supplements, Metabolism
The brain is pretty sensitive to nutrition, and some people are more sensitive than others. The brain likes to have a nice constant level of glucose and other nutrients that are
managed by a blood-brain barrier. It’s possible that changes in diet and diet supplementation could cause conditions that cause headache during exertion, either because the blood pressure gets elevated from the altered nutrition and then further elevated by the actual exertion so then you go from subclinical to actual pain. The nutritional factors could be something as simple as getting to much sodium in table salt and soy sauce, etc or from getting too much caffeine from energy drinks. Many energy drinks have a lot of ingredients, like Synephrine, that are meant to increase heart rate and alertness. Some other drinks are designed to give a ‘pump’ by causing vasodilation of blood vessels with arginine alpha keto-glutarate. The arginine is a precursor of Ntiric Oxide, which actually causes the vasodilation. Arginine is actually under consideration as a nutraceutical because it also prevents plaque in the coronary arteries because open blood vessels mean less turbulence and shearing stress on the inside of the coronary arteries. But some people complain of headaches when they drink too much arginine, which is usually consumed during a workout.
Hunger and starvation also causes headaches. Most individual metabolisms are set to get a meal every four hours. If you don’t get fuel at these intervals, your body breaks down muscle to get fuel from proteins stored in the muscle tissue, it releases glycogen stored in the muscles, it releases glycogen stored in the liver and it releases fat (lipolysis) from fat storage areas of the body. Some people are more sensitive to hunger stages, probably because the brain doesn’t get an ideal level of glucose and amino acids. This puts an individual in an inflamed state that can cause weakness, confusion and headache. Sometimes the headache doesn’t show until exertion is added because the added stress of exertion increases fuel demand and physiological and metabolic demands.
Exertion, High Blood Pressure
Exertion on its own can cause headaches or head rushes. Lifting a weight that is near, at, or beyond your one-repetition maximum can cause high levels of both systolic and diastolic blood pressure. If your blood pressure is already elevated, you have a greater chance of having head pain on lifting exertion. Often you may just have a little dizziness or see some floaters (visual disturbances) that look like red comets or ‘seeing stars.’ You are redlining your body when you are in this condition and you must proceed with caution. Make sure you aren’t holding your breath while under this extreme lifting stress, because you add pressure to your head and body. The resulting Valsalva maneuver, which drops your blood pressure because physiological receptors in your body sense the elevated pressure and cause a feedback mechanism that drops your blood pressure. In extreme cases the drop in pressure could give the visual disturbances and even cause you to faint.
If you notice that your resting blood pressure is getting up over 130/90 mm Hg it is going to be even higher during exertion compared to the exertional pressure of someone who has a healthier 124/80 mm Hg blood pressure at rest. Hypertension can be totally ‘silent’ of symptoms, but sometimes headaches will occur from high blood pressure alone even without exertion. Sometimes individuals with high blood pressure will get headaches during the exertion and then it immediately goes away. One individual noticed headaches with high rep biceps curl lifting at about 60% of one-repetition maximum. The pulsing headache was in the occipital region between the head and neck. A blood pressure check revealed a reading of 160/105 mm Hg. The individual was chronically lacking sleep and luckily discovered that a frequent meal at a favorite restaurant was high in sodium. Getting more rest and getting rid of the salt in the diet brought the blood pressure down to 128/82 mm Hg.
Lack of sleep increases stress hormones that can put the body in a state of elevated blood pressure and interfere with good fuel availability.
Chances are that if you are not well rested and you are not well nourished or you have an illness coming on, the symptoms of over-exertion will be exacerbated. Therefore, you should avoid max workouts when any of these three conditions exist. Don’t max out when you are sick or you are not nourished and rested.
Intense cardio, especially mixed with anaerobic bursts (like a hard game of basketball) can also affect the body’s physiology and metabolism and cause headaches, especially immediately following the workout or competition.
Stress and Tension, Posture and Body Mechanics
A good workout can relieve stress, But a workout while preoccupied with mental stress can cause constant tension of muscles and poor body mechanics that can cause head and neck pain. Keep your head and neck relaxed during lifting. Learn to always ground your forces to the earth and understand Center of Gravity. Newton’s Third Law is every action has an equal and opposite reaction. When you generate muscular force, that forces moves your body, but it also react with the earth at whatever contacts you have with the earth. If you are standing, the interaction is with your feet and the ground or floor. If you are seated in an exercise machine it might be where your back and glutes contact the seat of the machine.
Sinus Infections
These are the kind of sinus infections that are minor and are not involved with brain infection. In other words you are not too sick to work out. Minor sinus infections still obstruct breathing, which can limit oxygen intake and obstruct pressure release during exertion. It can also just add to tension and discomfort and plain old sinus pain and headache, which can be aggravated by exertion or body positions in activity that put the head lower than the rest of the body. Sinus cavities are affected by gravity in low head positions and nasal contents press on swollen tissues.
Environmental Exposure
Many toxins in the air can cause headache from chemical irritation or from allergens. Freshly varnished floors (such as wood basketball floors), indoor swimming pools with heavy chlorine, carbon monoxide from a nearby garage or busy intersection must also be considered.
Dust and allergens from plants can also affect sinuses and cause headache. Deep inhalation from exertion can exacerbate these conditions.
Also extreme heat, cold or dry air, or repetitive, noisy environments and cause headache conditions.
Substance Abuse
Alcohol, illegal drugs and tobacco contain toxins that can directly cause headaches and can cause physiological changes in the body that can cause headaches. A full hangover comes with a headache on its own. Milder hangovers can produce headaches on exertion and often depends on the intensity of the exertion.
Summary
Many times it is a combination of two or three or four factors that will bring a person to a threshold of headache pain.