Which activities are healthy ways to reduce stress?​

There are several methods, and it varies out from person to person: exercise is one of them which releases good-feeling hormones (endorphins). There is also meditation, deep breathing exercises,  any kind fo therapy that involves the 5 senses like musical therapy, aromatherapy (scented candles), imagery (happy stuff or relaxing stuff like imagining a waterfall) , or even biofeedback.