People grind their teeth in their sleep for a variety of reasons including stress and anxiety which are the most common causes of people grinding their teeth in their sleep.
So by reducing stress and possibly reducing anxiety you can sometimes stop the grinding of the teeth at night but there's really no full on cure for grinding teeth at night and it can also be caused by crooked teeth or an abnormal bite.
Getting exercise can help reduce your stress levels and anxiety and can sometimes help with curbing the grinding of the teeth at night.
I would also recommend wearing a teeth guard for grinding your teeth which you can usually buy at Walmart stores or other stores for pretty cheap.
The teeth guards will help prevent your from grinding and damaging your teeth at night.