The  most  common  type  of headache  is  tension headaches.  Approximately 90% of headaches  fall into  this  category.  People  with this  type  of headache  typically feel  like  they have  a  rubber band wrapped too  tightly around their  head.  The  level  of pain  can vary from  mild  to fairly severe  – in the worst  form,  pain  spreads  from  the  head and covers  the  shoulders, neck  and upper back.  Other unpleasant  symptoms  may also  be  present. For example,  your  scalp,  neck and  shoulder  may  be sore  and painful  to  touch.  You may also feel  extremely  tired  and easily irritated,  and may  have  to struggle  to concentrate.  Trouble  sleeping  and  a  diminished  appetite  are  also  common  symptoms.

Depending  on how  often  you  experience  them,  tension headaches  can  be  broken down into 3 different  classifications.  Episodic  headaches  are  usually sporadic  and  occur less  than  once  a  month. Frequent  tension headaches  happen  1-5 times  in a  given  month.  The  most  frequent  type  of tension headache  is  classified  as  chronic.   These  can occur  15 or more  days  per month,  which means  that sufferers  of this  type  of headache  are  in pain  for at  least  half  of their  waking hours.

Causes

What  causes  a  tension  headache?  As  far as  the  biomechanical  mechanisms  that  make  you  feel  pain are  concerned,  there  are  two schools  of thought.  The  first  school  of thought  states  that  tension headaches  are  primarily caused  by…tension.  This  theory holds  that  such factors  as  stress  and anxiety cause  muscles  in  your  face, neck  and scalp  to tense  up, causing your  headache.  However, some  researchers  today believe  that  tension  headaches  don’t  come  from  muscle  tension at  all,  but rather  from  imbalances  in brain  chemicals  and neurotransmitters.

For example,  researchers  are  now  able  to use  special  machine  called  an  electromyogram  to measure  muscle  contractions,  and  they have  not  found a  pattern  of increased  muscle  tension  that  is specific  to  tension headaches.  People  with tension  headaches  are  found to be  tense, but  not  any more  or less  tense  than  people  with migraines.  Additionally,  they show  alterations  in the  levels  of two very important  types  of brain  chemical:  serotonins  and endorphins.

Serotonin  helps  the  brain control  mood,  sleep and appetite,  and serotonin  imbalances  can also cause  clinical  depression. Endorphins  are  the  body’s  natural  painkillers.  Changes  in the  levels  of these  chemicals  interfere  with the  body’s  ability to  control  pain, and are  found in people  with both tension  headaches  and migraines.

No one  is  sure  what  causes  these  changes  in  brain chemicals.  The  only thing researchers  are  certain of right  now  is  that  there  is  a  connection  between  altered  levels  of these  neurotransmitters  and various  types  of headache.  However,  muscle  tension may still  be  a  major  contributing  factor  to tension  headache.