Adrenaline

Certain Warrior and Paragon skills are fueled by adrenaline rather than energy. It is gradually built up each time the Warrior or Paragon hits or is struck in combat, each such blow being added to the characters adrenaline level. Some skills increase the rate of adrenaline build up, while others expend it entirely.

Adrenaline Points
Adrenaline is not actually gained in strikes, but in points. Every adrenal skill stores its own adrenaline points displayed by rising flames from 0 until fully charged. See this table for approximate number of adrenaline points needed for skills.

1 4 "strikes" on Cleave does not equal 4 "strikes" on Sever Artery. The "Points needed" column increases linearly; the "adrenaline strikes needed" in the skill descriptions are a simplification. A "strike" of adrenaline in the skill description equals 20-25 points. A real "strike" of adrenaline gives 25 points.

Gaining adrenaline
Gaining adrenaline means every adrenal skill in your bar gains that many points. For every attack you make that hits, you gain 25 adrenaline points. For every 1% of health lost from your maximum, you gain 1 point of adrenaline. Runes count against the maximum health. Gain is calculated on a per-attack basis. For every 25% of your health lost, you gain approximately 1 "strike" of adrenaline--the equivalent of an attack landing. Note that health lost includes ranged attacks but excludes health degeneration. Commonly, 4 strike skills are charged in about 3 hits time, because you take some damage at the same time, assuming that the opponent is attacking you.


 * Soothing Images sets all adrenaline gain to 0. You can still use adrenaline-fueled attacks under Soothing Images if they are charged; the skill just prevents you gaining any more adrenaline until it ends.
 * Soothing causes all enemies in its area of effect to gain only 50% standard adrenaline.

Using adrenaline
You can only use adrenal skills that are fully charged with adrenaline. They cost 0 Energy. When you use an adrenal skill, that skill's adrenaline pool is emptied, and all other adrenal skills in your bar lose 25 points. These lost 25 points can be recovered with your next hit (including the adrenaline-fueled attack itself), or by taking as much damage as 25% of your maximum health.

Losing adrenaline
Losing adrenaline means every adrenal skill in your bar loses its full load of adrenaline. For attack skills with this attribute, the effect comes after the 25 points each skill gains if the attack hits, so all pools will be at 0. You lose all adrenaline after you have not been attacked, and do not attack for 20 seconds, or when you die.


 * Some warrior skills cause "...lose all adrenaline." These skills are: Hammer Bash, Heavy Blow, Wild Blow, Final Thrust, "On Your Knees!", Battle Rage, and Shove.
 * Any adrenal skill which is reset or disabled will lose all adrenaline and will not gain any new adrenaline until it has recharged. Diversion, and Shield Bash can be used to disable individual skills.  Blackout and Wail of Doom can disable multiple skills of an opponent.  Bestial Fury, Primal Rage, Shove, Marauder's Shot, and Tiger's Fury can disable your own skills.  Quivering Blade and Whirling Axe are disabled if blocked.
 * Sympathetic Visage and Ancestor's Visage causes a loss of all adrenaline when an adjacent foe enchanted with it is struck.

Skills that boost adrenaline

 * With Berserker Stance you gain 30 points every time you hit in melee (instead of 25).
 * With "For Great Justice!" all your adrenaline gain is increased by 50%, rounded down.
 * With Battle Rage you gain 50 points every time you attack.
 * With "To the Limit!" you gain 25 points for each foe in the area (max 25...125).
 * With Wary Stance you gain 35 points every time you block an attack skill.
 * With Auspicious Parry you gain 25...75 points and block an attack.
 * With Dragon Slash you gain 25...100 points if you hit.
 * With "You Will Die!" you gain 25...75 points if foe is below 50% health.
 * With Ferocious Strike you gain 25 points if your pet hits.
 * With Balthazar's Spirit you gain +2...5 points every time you take damage.
 * With Dark Fury you gain +25 points if you hit.
 * With "Lead the Way!" you gain 25 points (max 100) for each party member in earshot.
 * With Anthem of Fury all allies within earshot gain 25..75 points the next time they use an attack skill.
 * With Focused Anger you gain 1..120% more adrenaline for 45 seconds.
 * With Natural Temper you gain 33% more adrenaline for 4..9 seconds whilst not under an enchantment.
 * With Signet of Aggression you gain 25 points if you are under the effects of a shout or chant

Reference
Research done by Ensign and Silmor. Original GW Guru thread. Further discussion and research.