A FINE LAYER OF SALT GLAZES MY LIPS and I close my eyes, listening to a rush of hot mineral-rich water as it streams into the space beside me. I’m mostly submerged in a large thermal pool, positioned to take advantage of the underwater jets doing an exceptional job melting the knotted muscles behind my shoulders. Spanning the entire length of the wide stone wall at the far end of the pool facing me, a beautiful inset gas fireplace feeds warmth into the space, while firelight flickers against the glass and across the water’s surface.

Aligned at the room’s end across from one another, tall, leafless birch trees reach toward the ceiling, adding to the illusion of taking a dip in a deep alpine forest lake. Elements of Nordic nature and culture all come into play in the LivNordic Spa & Wellness space on board the elegant Viking Star, one of Viking’s extraordinary ocean-going vessels.

The fabulous spa space makes up the entire forward area of Deck One and proves one of the most wonderful at-sea experiences I’ve ever enjoyed. Along with the hot and cold areas, the spa’s multihead showers can target everywhere all at once, or just that one muscle crying out for attention. Separate men’s and women’s dressing areas each provide showers, lockers, large sauna cabins and cold plunge pools. While each also offers its own relaxation area, it’s the tranquil, firelit space near the pools that beckons.

From the corner of my eye, I have a partial view of a grotto filled with snow and ice, emanating a soft blue glow through the glass on one side. It’s across from the large steam chamber and separated by a wide area where heated stone beds, curved for optimal comfort, offer an inviting space to relax.

Thanks to plenty of time exploring Iceland and Scandinavia, I’m familiar with the Nordic bathing ritual of alternating hot and cold experiences to stimulate the immune system and relax the body. A host of medical studies support this practice, detailing how the use of water in its various forms — ice, steam and liquid — can offer relief from a host of conditions that include arthritis and joint and muscle pain, while enhancing cardiovascular health and an improved sense of overall well-being.

It’s that well-being sensation I’m seeking. In the midst of processing all of that hot vs. cold information intellectually, I’m still mentally cringing at leaving the comfort of the hot mineral pool, carefully observing as others move in and out of the snow-filled grotto. But since nothing ventured equals nothing gained in the world of travel, I reluctantly pull myself from the hot water and enter the icy cave.

Immediately I’m surrounded by the cave’s ethereal blue light. My toes dig in to the soft snow, and after an initial gasp, I clear a spot on one of the stone benches positioned within, noticing how snowflakes fill the crevices and tiny shelves within the lava rock walls. Four minutes, counted out on the spa’s wall clock, pass swiftly, and I leave feeling a rush of peacefulness wash over me.

Snow grotto © VIKING OCEAN CRUISES

The cold session only makes the next destination on my thermal route — the scented steam chamber — all the more delicious. I choose a seat against the wall and press my shoulders into the stone, physically absorbing the warmth.

The result is heavenly. For the next hour, I make a path through the suite, choosing the hot pool, whirlpool or steam bath alternating with the cold option of the snow cave or a session beneath a bucket filled with icy water. A firm pull on the bucket’s chain releases a frigid cascade over my head and body and acts as permission to immediately head someplace warmer. Between hot and cold sessions, there’s time to relax on one of the poolside loungers beneath a thick towel or to stretch out on one of the heated stone beds with a pillow beneath my head.

The next day, I arrive at the spa in time for a sauna session before my Swedish massage. I’d hesitated over my treatment choice, finally deciding I should play out the Nordic theme as fully as possible. My therapist questions me about any especially tight areas and proceeds to deliver a deep-tissue version of the traditional Swedish therapy, using her hands and lower arms to roll and knead my muscles in a rhythmic motion that mimics the movement of the ship.

When her fingertips find the muscles beneath my shoulder blades, she adds a swift, tapping vibration that enhances my relaxation. At the end of my session, she gives me instructions to make use of the thermal suite as much as possible during the cruise, suggesting that moving between the steam bath and snow cave would be particularly helpful.

Post-massage, it’s time for afternoon tea service in the Wintergarden. By the time I arrive, a string quartet is already playing. Music floats toward the glass ceiling, supported by a lacy network of golden Scandinavian wood, creating a tranquil space and reminding me of a vast nest suspended between the sea and sky. A smiling waiter notes my tea selection and returns soon with a teapot and a tiered stand of savory sandwiches, lovely cakes and an array of still-warm scones — for me, the ideal way to wrap up a relaxing day at sea.