Caffeine cut-off

What it is

Picking a fixed time of day after which you don’t have coffee, tea, energy drinks or other caffeine, and sticking to it every day.

What the research says

Caffeine can stay in the body for hours, and people differ a lot in how it affects them.

• Timing and sleep. We haven’t found a source strong enough to support a single “stop X hours before bed” rule. The effect depends on how much you have, how used to it you are, when you go to bed, and your own metabolism.
• Why people differ. Genes, medication, smoking, hormones and habits all change how fast caffeine is cleared, so no single factor tells you how you’ll respond.

That’s the case for testing your own cut-off rather than following a rule.

How to try it

1. Pick your cut-off (for example 12:00 or 14:00) and write it down.
2. Count every source, including tea, cola, pre-workout and dark chocolate.
3. Keep your total the same, just earlier, so you test timing and not amount.
4. Run it for at least two weeks. The first days can feel different while you adjust.