Sublime

The second key finding is that our bodies follow what are known as ultradian rhythms—ninety-minute periods at the end of which we reach the limits of our capacity to work at the highest level.

The second key finding is that our bodies follow what are known as ultradian rhythms—ninety-minute periods at the end of which we reach the limits of our capacity to work at the highest level. It’s possible to push ourselves past ninety minutes by relying on coffee, or sugar, or by summoning our own stress hormones, but when we do so we’re overridi

fact, this is partly how probiotics are believed to work: they consist of species that aren’t normally resident in our microbiomes, flowing through us to make sure our guards aren’t snoozing on the job.

Even so, Satchin’s research is far more epic than the buildings. He’s found that ketones act as miniature alarm bells, rousing the brain cells that regulate the circadian rhythm and instructing the body to switch into an active, awake state.11 A small rise in ketones from fasting provides a burst of energy, which likely evolved to help you have a m

Protein and sugar.

For humans, societally imposed cycles, such as the schedule of the work or school day and regular mealtimes, can become zeitgebers as well.

Metabolic health expert Dr. Casey Means

When we are physically active, skeletal muscle releases anti-inflammatory cytokines called myokines,20 but modern lifestyles increasingly limit the occasions for strenuous