Friends:

What Intentional Actions (Kamma) influence Life-Length?

A student once asked the Buddha:
Master Gotama, what is the cause and condition why some human beings
here are short-lived, while other human beings are long-lived?



The Blessed Buddha then explained:
Here, friend, some man or woman kills living beings and is murderous,
bloody-handed, enjoying rage and violence, cruel to all living beings!
Because of intending and undertaking such action, at the breakup of
the body, right after death, such one reappears in a state of affliction,
in a painful destination, in the purgatory, or even in the hells...
But if such one at the breakup of the body, after death, is not reborn
in an awful state, a painful destination, the purgatory, or in the hells,
but instead comes back to the human state, then wherever such one is
reborn he is short-lived#! These are the actions, friend, that leads to a
short future life, namely, kill, murder, bloody-handed brutality, slaughter,
violence, and cruelty towards all living beings...
However, friend, any man or woman, who is avoiding killing of any living
beings, who abstains from killing any living beings, with rod and weapon
laid down, gentle & kind, such one dwells friendly to all living beings...
Because of intending & undertaking such action, at breakup of the body,
right after death, such one reappears in a pleasurable & happy destination,
even in the divine dimensions! But if at the breakup of the body, right after
death, such one is not reborn in a happy destination, in the heavenly worlds,
but instead comes back to a human state, then wherever such one reappears,
such one is long-lived%! This way, friend, leading to long life, is namely,
avoiding the killing of any living beings, refraining from killing living beings,
with stick and weapon laid aside, gentle and kind, one abides compassionate
to all sentient beings, completely harmless to all living & breathing beings...!

Notes:
#: Such one escapes hell, because the evil kamma is modified by past good!
%: Such one misses heaven, because the good kamma is modified by past evil!

Source:
The Moderate speeches of the Buddha: The short speech on Action. MN 135
http://www.pariyatti.com/book.cgi?prod_id=25072X Full Text:
http://www.accesstoinsight.org/canon/sutta/majjhima/mn135a.html



For details on the mechanics of Kamma = Intentional Action see:
http://What-Buddha-Said.net/drops/II/Kamma_is_intention.htm
http://What-Buddha-Said.net/drops/II/Buddha_on_Kamma.htm
http://What-Buddha-Said.net/drops/II/Good_Action_dilutes_Evil_Kamma.htm
http://What-Buddha-Said.net/drops/II/Kamma_leading_to_short_&_long_life.htm

http://What-Buddha-Said.net/drops/II/Kamma_leading_to_Health_&_Sickness.htm
http://What-Buddha-Said.net/drops/II/Kamma_leading_to_Low_or_High_Birth.htm
http://What-Buddha-Said.net/drops/II/Kamma_leading_to_Wealth_or_Poverty.htm

http://What-Buddha-Said.net/drops/II/Kamma_leading_to_Beauty_&_Ugliness.htm
http://What-Buddha-Said.net/drops/II/Effect_of_Action_is_Delayed.htm
http://What-Buddha-Said.net/drops/II/Kamma_leading_to_Power_or_Disrespect.htm

http://What-Buddha-Said.net/drops/II/Evil_Kamma_enhances_other_Evil_Kamma.htm
http://What-Buddha-Said.net/drops/II/Good_Action_enhances_other_Good_Kamma.htm
http://What-Buddha-Said.net/drops/II/Kamma_leading_to_Stupidity_or_Intelligence.htm

Kamma and Life Length...