Sauna and Cold Plunge in the Summer: Nervous System Benefits and Glowing Skin
The assumption that summer is the wrong time for a sauna seems intuitive at first. The body is already hot, already working to regulate temperature, and more heat seems counterproductive. But the research on summer sauna benefits suggests otherwise.
What Heat Does to the Body in Summer
When the body is exposed to sustained heat, whether from the natural environment or from a sauna, it adapts. Core temperature rises, heart rate increases, and the cardiovascular system responds by dilating the blood vessels near the skin's surface to dissipate heat. This vasodilation underlies many of the circulatory benefits of regular thermal practice, and in summer, the body is already primed for it. Ambient summer heat has been conditioning the cardiovascular system toward easier vasodilation for weeks, which means the circulatory benefits accumulate more readily than they would in the cold of winter. Research suggests women respond particularly well to regular sauna use: a 2025 study in Scientific Reports found measurable cardiovascular adaptation in women across repeated sessions, with the body showing progressive adjustment to heat exposure.
After the vasodilation of the sauna, cold water causes rapid vasoconstriction, driving blood back toward the core and the major organs. The alternation between these two states creates what is sometimes called a vascular workout, as the blood vessels expand and contract repeatedly, improving their tone and responsiveness over time. During the summer, when the body is already carrying the mild inflammatory load of heat, pollution,and sun overexposure, the cold plunge functions as a circulatory reset that the heat has primed the body for.
Cortisol, Sleep, and the Summer Nervous System
July and August bring depletion that differs from winter fatigue. The longer days, the social density of the season, the unspoken pressure to make the most of summer, and the disrupted sleep that warm nights produce all accumulate into a cortisol load the body carries toward the end of the season. Contrast therapy addresses this directly.
The cold plunge activates the vagus nerve and shifts the autonomic nervous system toward parasympathetic dominance, the rest-and-digest state that chronic stress suppresses. Research on cold water immersion and cortisol finds consistent reductions in circulating cortisol following cold exposure, with effects on mood and sleep quality measurable in the hours following a session. Heat exposure increases plasma volume, which reduces the cardiovascular strain of daily activity so the body operates from a lower baseline of effort in the days that follow.
Sauna Skin Benefits
The glowy skin associated with a post contrast therapy is a circulatory response; it comes from vasodilation delivering oxygen and nutrients to the skin's upper layers, followed by the cold plunge reducing surface inflammation. The result is clearer, more even skin, that feels toned and revived. During the hotter months, when sun exposure, dehydration, and heat stress are all working against that baseline, a contrast therapy session functions as a circulatory reset for the skin as much as for the deeper systems it benefits.
Contrast Therapy As Part of Your Bowen Island Day Trip from Vancouver
The temperate rainforest on Bowen Island in July is at its most aromatic. The conifers are releasing phytoncides at their highest summer concentration, compounds shown to reduce cortisol and increase natural killer cell activity through olfactory intake. The cold plunge at Mist draws from a spring aquifer beneath the property, carrying filtered water that has been moving through rock and root.
The outdoor eucalyptus shower, the fire lounge with an immersive forest view, the live soundtrack of the forest: these are the conditions in which the nervous system decompresses. During the hotter months, when the city has been loud, crowded, and sticky, the temperate rainforest in the heart of Bowen Island offers refreshment.
Mist Thermal Sanctuary sits within this forest, a 20-minute ferry ride from Horseshoe Bay in West Vancouver. Each of the three private units includes an outdoor eucalyptus shower, wood-fired sauna, cold plunge and transition tub, dressing suite with a fully stocked herbal tea bar, and a fire lounge surrounded by ferns and towering conifers. Sessions run 90 or 120 minutes and are booked per unit, meaning the circuit is yours alone, or with up to three guests, for the duration.
References
Sauna heating and cold water immersion in women (Scientific Reports, 2025): https://www.nature.com/articles/s41598-025-29035-w
Cold water immersion and cortisol: https://www.cambridge.org/core/journals/bjpsych-advances/article/beyond-the-cold-baths-contemporary-applications-of-coldwater-immersion-in-the-treatment-of-clinical-depression-and-anxiety/F285E3B83C4D0E43D10883021BCDD55F
Contrast therapy and circulation: https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2019.00336/full
Forest bathing and phytoncides: https://link.springer.com/article/10.1007/s00484-019-01717-x
Heat exposure and plasma volume: https://www.foundmyfitness.com/topics/cold-exposure-therapy
Disclaimer: This post is for informational purposes only and should not be taken as medical advice. Cold-water immersion and thermal practices can affect people differently depending on your health, medications, and life stage. If you are pregnant, in perimenopause, living with a medical condition such as heart disease, or taking medication, speak with your healthcare provider before beginning.