There’s discussion, too, of cold water therapy as a way of boosting one’s immune system. More study is needed there, too.

Wim Hof Method offers important mental benefits. Cold exposure recharges your nervous system and brain, increasing adrenaline, serotonin and norephineprine, which help boost mood. The method is named for Dutch extreme athlete Wim Hof, an ardent advocate of cold water therapy. His method includes a specific breathing pattern, as well.

Not for everyone

Some groups should avoid the practice, including people who have:

• Circulation problems such as peripheral vascular disease.
• Frostbite history.
• Raynaud’s disease.
• An open wound or recent surgery.
• People with heart disease, high blood pressure, diabetes, venous stasis and cold agglutinin disease should avoid the practice.
• It’s not safe for those who are prone to seizures or fainting.

Experts say to talk to your doctor before taking the plunge.