The findings reinforce the value of varied thermal experiences – both dry and wet / photo: shutterstock/alenacepl
Hot water bathing may bring unique health benefits compared to saunas, according to a new study published in the American Journal of Physiology*.
Researchers from the University of Oregon found that soaking in a hot tub raises core body temperature more than dry or infrared saunas, triggering strong cardiovascular and immune responses.
Lead author Jessica Atencio says: “Hot water immersion was the most impactful when it came to increasing core body temperature ... causing an increase in blood flow, which is beneficial for vascular health.”
Quicker response Researchers monitored body temperature, blood pressure, heart rate, cardiac output (the amount of blood the heart pumps per minute), immune cell populations and blood biomarkers of inflammation. Data was collected before, during and after subjects soaked in a hot tub, sat in traditional dry heat and also in far-infrared saunas.
Of the three types of heat therapy, only hot water immersion produced an inflammatory response, as measured by the levels of inflammatory cytokines in the blood – an immune signalling molecule that drives immune cell populations.
Atencio explains: “When you’re submerged in water, the body can’t cool efficiently through sweating, so immersion produces more robust temperature increases.”
Co-author Christopher Minson, who has studied heat therapies for over two decades, adds: “Heat therapy can be a peaceful, cultural or social experience, which contributes to its health benefits. It’s also an option for people unable to exercise.”
Mix it up With demand for recovery and social wellness growing across spa, fitness and wellness sectors (see p54), the findings reinforce the value of offering a range of thermal options.
Liz Terry, the editorial director of Spa Business, notes: “Having new insights that drive purchasing decisions and business development is critical.
“We already know the efficacy of both traditional and infrared saunas, now research shows that warm water bathing, when done safely, is a powerful part of the mix.”
*Atencio, JK et al. Comparison of thermoregulatory, cardiovascular, and immune responses to different passive heat therapy modalities. American Journal of Physiology, 2025.
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The findings reinforce the value of varied thermal experiences – both dry and wet / photo: shutterstock/alenacepl
Hot water bathing may bring unique health benefits compared to saunas, according to a new study published in the American Journal of Physiology*.
Researchers from the University of Oregon found that soaking in a hot tub raises core body temperature more than dry or infrared saunas, triggering strong cardiovascular and immune responses.
Lead author Jessica Atencio says: “Hot water immersion was the most impactful when it came to increasing core body temperature ... causing an increase in blood flow, which is beneficial for vascular health.”
Quicker response Researchers monitored body temperature, blood pressure, heart rate, cardiac output (the amount of blood the heart pumps per minute), immune cell populations and blood biomarkers of inflammation. Data was collected before, during and after subjects soaked in a hot tub, sat in traditional dry heat and also in far-infrared saunas.
Of the three types of heat therapy, only hot water immersion produced an inflammatory response, as measured by the levels of inflammatory cytokines in the blood – an immune signalling molecule that drives immune cell populations.
Atencio explains: “When you’re submerged in water, the body can’t cool efficiently through sweating, so immersion produces more robust temperature increases.”
Co-author Christopher Minson, who has studied heat therapies for over two decades, adds: “Heat therapy can be a peaceful, cultural or social experience, which contributes to its health benefits. It’s also an option for people unable to exercise.”
Mix it up With demand for recovery and social wellness growing across spa, fitness and wellness sectors (see p54), the findings reinforce the value of offering a range of thermal options.
Liz Terry, the editorial director of Spa Business, notes: “Having new insights that drive purchasing decisions and business development is critical.
“We already know the efficacy of both traditional and infrared saunas, now research shows that warm water bathing, when done safely, is a powerful part of the mix.”
*Atencio, JK et al. Comparison of thermoregulatory, cardiovascular, and immune responses to different passive heat therapy modalities. American Journal of Physiology, 2025.
Read more from this issue of Spa Business magazine
Spa people: Tim Fu
Leading a wellness architecture project in Slovenia that’s one of the first in the world to use AI in all stages of design
Spa people: Kayley Thomas
Lush is famous for its bath bombs and retail empire, but the co-founder of its day spa concept reveals why its 19 global spa facilities are so essential
Spa people: Colin Mcilheney
We find out more about Colin Mcilheney, the man who created the ISPA US Spa Industry Study and has been analysing the sector’s performance ever since
News report: Map of luxury
New research by WATG shows emerging wealth hubs in India, the Gulf, Southeast Asia and Africa are reshaping luxury travel demand
Interview: Chris Norton
The CEO of Equinox Hotels tells Katie Barnes how the uber-cool brand is scaling its bold fusion of fitness, spa and luxury
Ask an expert...: Recovery
From cryo to compression to contrast bathing, Julie Cramer investigates why and how spas and resorts are integrating recovery packages
Research: Behind the boom
What are the hidden messages in the latest US study by ISPA? Colin Mcilheney digs beneath the surface
Research: Bigger picture
Rising salaries and shifting consumer expectations – two new surveys by the UKSA and GSG reveal the trends impacting UK spa operators
Sponsored: Lemi - Good sensations
Lemi’s Venice Head Spa combines the beauty of Italian design with fine-tuned technology to provide the ultimate top-to-toe treatment station for spas
Sponsored: G.M. COLLIN – Smooth operator
The new toner from G.M. Collin represents a ‘gold standard’ in leave-on liquid exfoliation for smooth and radiant results, without the irritation of a scrub
Sponsored: TechnoAlpin – Snow for all seasons
TechnoAlpin’s magical Snowroom installation at the Alpenrose resort brings the Austrian landscape and feel-good nature factor to its wellbeing experience
First person: Costa Blanca cure
Jane Kitchen visits Spain to compare and contrast two world-class medi-wellness clinics: well-established SHA and ambitious newcomer ZEM
Sponsored: Gharieni Group – Tech-powered recovery
The new brand in the Gharieni Group portfolio – Metawell – is delivering what today’s wellness clients are seeking most – deep recovery and mind-body renewal
Sponsored: BC Softwear – Human touch
While touchless therapies are a positive addition to spas, nothing can replace the healing power of human touch, says Barbara Cooke
Sponsored: Yon-ka – A potent blend
Yon-Ka’s new Serum Omega is a potent blend of Omega 3, 6 and 9 to target
dry, stressed-out skin and deliver a calm and nourishing client experience
Menu engineering: At your service
Self-playing gongs in Sweden, surfing therapy in Morocco and Ananda launches holistic diabetes management programme in India
Four Seasons Resort The Nam Hai in Hoi An, Vietnam, has put together a Global Wellness Day
(GWD) agenda with activations rooted in nature and shaped by four pillars of Joy – in
alignment with the day’s theme #JoyMagenta.
The Global Wellness Summit (GWS) will celebrate its 20th anniversary at the 2026 event in
Phuket, Thailand, later this year with the theme: The Science, Art and Soul of Wellness.
Auko, an all-inclusive development, is opening in Phong Nha in Vietnam in Q3 2026, with a
series of 30 tented eco-lodges and wellness hospitality operations by Lumina Wellbeing.
Therme Manchester’s 28-acre development, which will include interconnected glass pavilions
that measure 65,000sq m, will be the largest bathing and wellbeing attraction in the world once
complete, according to prof David Russell, CEO of Therme UK.
Naples Beach Club, a Four Seasons Resort, has opened a 2,800sq m spa called The Sanctuary,
with the design and concept inspired by the Native American people that populated Florida’s
Southwest coast – the Calusa.
Swire Hotels’ luxury hospitality brand Upper House has revealed it will roll out its two-day
House of Healing retreats at its three hotels in Hong Kong, Chengdu and Shanghai.
LVMH-owned beauty house Guerlain will launch up to five spas with partners a year as part of
its plan to expand globally, according to the brand’s international spa and wellness director,
Diane Davody.
A new global study by Kevin Kelly and Peter Yesawich, called WELLSurvey 2.0, has revealed
more than half of consumers in the UK, US and Germany would not choose numerous high-
profile wellness resort brands for a future trip.
Luxury hospitality and wellness pioneer Jeremy McCarthy has launched Leisure Alchemy, a
digital platform that will provide professionals with strategic guidance on how to build
transformational leisure experiences that drive profit.
