The trick is known as the "4-7-8 Method," and while its origins lay in ancient traditions of yoga, Weil says it's thoroughly scientifically vetted. The simple breathing technique works to calm stress by activating your parasympathetic nervous system, also known as "rest and digest mode." Here's all you have to do, according to Vogue:

Breathe in through your nose for a count of four seconds.

Hold your breath for seven seconds.

Exhale for eight seconds, making a "whoosh" sound through pursed lips.

Repeat up to four times.

The 4-7-8 method can be used to kill stress and calm your body any time of the day, not just at bedtime. And the more consistently you use the technique, the better it works. So give it a try and see if this might be the answer to your sleep challenges.