Here is a recent news article from “The Independent” UK: “Effects of anger last at least a week, study shows” (By Roger Dobson, Published: 11 November 2007).
Heather Mills needs to calm down. Outbursts like her infamous rant on GMTV may still be having an adverse effect on her health a week later, according to scientists.
New research shows that blood pressure increases during a bout of anger and that it still rises seven days later when the row is remembered. “Even after a week, there is no sign of any reduction of the effect,” say researchers, who report their findings in the International Journal of Psychophysiology this week. Anger has been linked to a higher risk of heart disease and other health problems. Research suggests that hardening of the arteries seems to advance faster in people who score high in anger and hostility tests. One theory is that stress hormones constrict blood vessels, raise blood pressure and speed up the heartbeat. It had been thought that these effects would disappear when the row was over. Researchers at the University of California and Columbia University looked at longer-term effects of anger triggered during a laboratory experiment with volunteers. “If cardiovascular responses are damaging to the cardiovascular system, then stressful events have the potential to continue to do harm long after they are ended.”
So now we have scientific evidence of anger being linked to a higher risk of heart disease and other health problems. In Chinese we called it “Anger fire attack heart.” In Chinese medicine we believe that anger will also injury the liver so anger does a lot of mischief with our health. So how can we control our anger? Below is an example from Sakyamuni Buddha:
Here is the Akkosa Sutta/discourse, from the Tipitaka, translated from the Pali by Acharya Buddharakkhita.
Once Sakyamuni Buddha was staying at Rajagaha in the Bamboo Grove near the Squirrels’ Feeding Place. Now the brahman Akkosa Bharadvaja heard this: “The brahman Bharadvaja, it seems, has become a monk under the Great Monk Gotama.” Angry and unhappy, he went to where the Buddha was. Having approached to Buddha, he abused and criticized Buddha in foul and harsh words.
Thus reviled, Buddha spoke to the brahman Akkosa Bharadvaja: “Well, brahman, do friends, confidants, relatives, kinsmen and guests visit you?”
“Yes, Gotama, sometimes friends, confidants, relatives, kinsmen and guests do visit me.”
“Well, brahman, do you not offer them snacks or food or tidbits?”
“Yes, Gotama, sometimes I do offer them snacks or food or tidbits.”
“But if, brahman, they do not accept it, who gets it?”
“If Gotama, they do not accept it, I get it back.”
“Even so, brahman, you are abusing us who do not abuse, you are angry with us who do not get angry, you are quarrelling with us who do not quarrel. All this of yours we don’t accept. You alone, brahman, get it back; all this, brahman, belongs to you.
“When, brahman, one abuses back when abused, repays anger in kind, and quarrels back when quarrelled with, this is called, brahman, associating with each other and exchanging mutually. This association and mutual exchange we do not engage in. Therefore you alone, brahman, get it back; all this, brahman, belongs to you.”
“People, including the king, know the Venerable Gotama thus: ‘The Monk Gotama is the Worthy One.’ When does the Venerable Gotama become angry?”

Said the Buddha:
“Where is anger for one freed from anger, who is subdued and lives perfectly equanimous, who truly knowing is wholly freed, supremely tranquil and equipoised?
He who repays an angry man in kind is worse than the angry man; [he] who does not repay anger in kind, he alone wins the battle hard to win.
He [who repays in kind] promotes the weal [wounds] of both, his own, as well as of the other.
Knowing that the other man is angry, he mindfully maintains his peace and endures the anger of both, his own, as well as of the other, even if the people ignorant of true wisdom consider him a fool thereby.”

The discourse goes on to say that this angry Brahman relented, became an ordained monk, and reached enlightenment. He became an Arahant too (a perfect man according to Hinayana Buddhism).

The phrase “awake man” describes Buddha because he can stay awake (in his enlightened state) and is aware (of the true nature of the universe) at anytime and in anyplace. When you want to learn Zen Buddhism or meditation it means you also want to be an “awake man”. So the best way to practice is when you are angry; you should be aware at the same time so you can calm down right away and not let the anger control you.