This goes together nicely with the Aestivation Hypothesis (https://arxiv.org/abs/1705.03394).

If a civilisation puts itself on hold for a trillion years, just waiting around doing nothing, then when it wakes up the universe is much colder and it can do computations 10^30 times more efficiently. If the civilization consists of minds running on computers then they've increased their own lifespans by the same factor.