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Acute effects of sauna bathing on cardiovascular function

Authors:
Tanjaniina Laukkanen at University of Eastern Finland
Tanjaniina Laukkanen
Setor Kunutsor at University of Manitoba
Setor Kunutsor
Francesco Zaccardi at University of Leicester
Francesco Zaccardi
Earric M Lee at Montreal Heart Institute
Earric M Lee
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Emerging evidence suggests beneficial effects of sauna bathing on the cardiovascular system. However, the effects of sauna bathing on parameters of cardiovascular function and blood-based biomarkers are uncertain. We aimed to investigate whether sauna bathing induces changes in arterial stiffness, blood pressure (BP), and several blood-based biomarkers. We conducted an experimental study including 102 participants (mean age (SD): 51.9 (9.2) years, 56% male) who had at least one cardiovascular risk factor. Participants were exposed to a single sauna session (duration: 30 min; temperature: 73 °C; humidity: 10-20%). Cardiovascular as well as blood-based parameters were collected before, immediately after, and after 30-min recovery. Mean carotid-femoral pulse wave velocity was 9.8 (2.4) m/s before sauna and decreased to 8.6 (1.6) m/s immediately after sauna (p < 0.0001). Mean systolic BP decreased after sauna exposure from 137 (16) to 130 (14) mmHg (p < 0.0001) and diastolic BP from 82 (10) to 75 (9) mmHg (p < 0.0001). Systolic BP after 30 min recovery remained lower compared to pre-sauna levels. There were significant changes in hematological variables during sauna bathing. Plasma creatinine levels increased slightly from sauna until recovery period, whereas sodium and potassium levels remained constant. This study demonstrates that sauna bathing for 30 min has beneficial effects on arterial stiffness, BP, and some blood-based biomarkers. These findings may provide new insights underlying the emerging associations between sauna bathing and reduced risk of cardiovascular outcomes.
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Journal of Human Hypertension (2018) 32:129–138
https://doi.org/10.1038/s41371-017-0008-z
ARTICLE
Acute effects of sauna bathing on cardiovascular function
Tanjaniina Laukkanen1●Setor K. Kunutsor2●Francesco Zaccardi 3●Earric Lee 4●Peter Willeit 5,6 ●
Hassan Khan7●Jari A. Laukkanen 1,8
Received: 1 July 2017 / Revised: 3 September 2017 / Accepted: 19 September 2017 / Published online: 21 December 2017
© Macmillan Publishers Limited, part of Springer nature 2018
Abstract
Emerging evidence suggests beneficial effects of sauna bathing on the cardiovascular system. However, the effects of sauna
bathing on parameters of cardiovascular function and blood-based biomarkers are uncertain. We aimed to investigate
whether sauna bathing induces changes in arterial stiffness, blood pressure (BP), and several blood-based biomarkers. We
conducted an experimental study including 102 participants (mean age (SD): 51.9 (9.2) years, 56% male) who had at least
one cardiovascular risk factor. Participants were exposed to a single sauna session (duration: 30 min; temperature: 73 °C;
humidity: 10–20%). Cardiovascular as well as blood-based parameters were collected before, immediately after, and after
30-min recovery. Mean carotid–femoral pulse wave velocity was 9.8 (2.4) m/s before sauna and decreased to 8.6 (1.6) m/s
immediately after sauna (p<0.0001). Mean systolic BP decreased after sauna exposure from 137 (16) to 130 (14) mmHg (p
<0.0001) and diastolic BP from 82 (10) to 75 (9) mmHg (p<0.0001). Systolic BP after 30 min recovery remained lower
compared to pre-sauna levels. There were significant changes in hematological variables during sauna bathing. Plasma
creatinine levels increased slightly from sauna until recovery period, whereas sodium and potassium levels remained
constant. This study demonstrates that sauna bathing for 30 min has beneficial effects on arterial stiffness, BP, and some
blood-based biomarkers. These findings may provide new insights underlying the emerging associations between sauna
bathing and reduced risk of cardiovascular outcomes.
Introduction
Sauna bathing, a form of passive heat therapy, is commonly
used for relaxation and pleasure purposes [1,2]. Repeated
sauna therapy has been shown to increase left ventricular
ejection fraction and reduce plasma levels of norepinephrine
and brain natriuretic peptide and increase the 6-min walk
distance [3]. After 1 week of repeated sauna exposure
(twice a day) in 10 healthy male volunteers, diastolic blood
pressure (DBP) was shown to decrease substantially [4].
Warm water immersion, which is also a form of passive
heat therapy, is associated with health benefits that include
improved endothelial and microvascular function as well as
reduced arterial stiffness (AS) and BP [5,6]. Passive heat
therapy (hot tub) improves cutaneous microvascular func-
tion by enhancing nitric oxide-dependent dilation in
sedentary humans [5]. It has been demonstrated that sauna
exposure results elevations in core temperature and changes
in cardiovascular hemodynamics, such as cardiac output
and vascular shear stress, which are similar to the effects of
exercise, and thus may provide an alternative means of
improving health [6]. In a 2-week trial of once-a-day
infrared-sauna exposure for patients with cardiovascular
*Jari A. Laukkanen
jariantero.laukkanen@uef.fi
1Institute of Public Health and Clinical Nutrition, University of
Eastern Finland, Kuopio, Finland
2Translational Health Sciences, Bristol Medical School, University
of Bristol, Learning and Research 11 Building (Level 1),
Southmead Hospital, Bristol, UK
3Diabetes Research Centre, Leicester General Hospital, University
of Leicester, Leicester, UK
4Department of Biology of Physical Activity, University of
Jyväskylä, Jyväskylä, Finland
5Department of Public Health and Primary Care, University of
Cambridge, Cambridge, UK
6Department of Neurology, Medical University Innsbruck,
Innsbruck, Austria
7Emory University, Atlanta, GA, USA
8Central Finland Health Care District, Department of Internal
Medicine, Jyväskylä, Finland
Electronic supplementary material The online version of this article
(https://doi.org/10.1038/s41371-017-0008-z) contains supplementary
material, which is available to authorized users.
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Content courtesy of Springer Nature, terms of use apply. Rights reserved
... A decrease in blood pressure, improved arterial elasticity and a temporary increase in blood cell parameters such 4 as hemoglobin levels, leukocyte and platelet counts were observed. These effects may contribute to long-term protection against arterial stiffness and reduced risk of cardiovascular disease and mortality, as shown in the studies we cited earlier (10). Studies on the effects of sauna bathing show that regular use has numerous benefits for cardiovascular health. ...
... SBP averaged 137 mmHg before the sauna session, 130 mmHg immediately after, and 130 mmHg after 30 minutes of rest. Diastolic blood pressure (DBP) values were 82 mmHg before, 75 mmHg after the sauna bath, and 81 mmHg after a 30-minute rest, respectively, suggesting that sauna bathing may have health benefits for patients with cardiovascular risk factors (10,12). A more recent 2019 study, also conducted on participants without a heavy health history, found similar results. ...
Sauna and health: How regular sauna sessions affect the body's health
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Sauna use, practiced for thousands of years, has its roots in Finnish culture, where it was considered an essential part of health and hygiene. In recent years, a growing body of scientific research has confirmed the numerous health benefits associated with regular sauna use. This research review focuses on the effects of sauna sessions on the body's health, with particular emphasis on the cardiovascular system, blood pressure, respiratory system and urinary system. Analyses show that regular sauna use contributes to lowering the risk of cardiovascular disease by reducing blood pressure and improving the lipid profile. In addition, sauna has a beneficial effect on lung function, reducing the risk of diseases such as chronic obstructive pulmonary disease and pneumonia. It is also worth noting that sauna baths are safe for patients with kidney disease, as confirmed by research results. These indications underscore the importance of regular sauna sessions as a form of health support, helping to improve quality of life and long-term well-being.
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... Growing evidence demonstrates that whole-body heat therapy may reduce all-cause mortality (Laukkanen et al. 2015(Laukkanen et al. , 2018a, fatal cardiovascular disease (Laukkanen et al. 2015(Laukkanen et al. , 2018a, stroke (Kunutsor et al. 2018), dementia , and respiratory disease . These benefits may be mediated, in part, through improvements in cardiovascular function including improvements in cardiac autonomic nervous system balance (Laukkanen et al. 2019) and reductions in blood pressure (Brunt et al. 2016;Laukkanen et al. 2018b), arterial stiffness (Brunt et al. 2016;Laukkanen et al. 2018b), and intima-media thickness (Brunt et al. 2016); metabolic parameters, such as blood lipids (Pilch et al. 2010; Gryka et al. 2014) and glucose (Hooper 1999); and inflammation Hoekstra et al. 2018). Notably, there are marked differences in the effect of heat exposure on glycemic parameters depending on whether they are measured after acute or chronic exposure and if the heating intervention entails whole-body or partial-body heat exposure. ...
... Growing evidence demonstrates that whole-body heat therapy may reduce all-cause mortality (Laukkanen et al. 2015(Laukkanen et al. , 2018a, fatal cardiovascular disease (Laukkanen et al. 2015(Laukkanen et al. , 2018a, stroke (Kunutsor et al. 2018), dementia , and respiratory disease . These benefits may be mediated, in part, through improvements in cardiovascular function including improvements in cardiac autonomic nervous system balance (Laukkanen et al. 2019) and reductions in blood pressure (Brunt et al. 2016;Laukkanen et al. 2018b), arterial stiffness (Brunt et al. 2016;Laukkanen et al. 2018b), and intima-media thickness (Brunt et al. 2016); metabolic parameters, such as blood lipids (Pilch et al. 2010; Gryka et al. 2014) and glucose (Hooper 1999); and inflammation Hoekstra et al. 2018). Notably, there are marked differences in the effect of heat exposure on glycemic parameters depending on whether they are measured after acute or chronic exposure and if the heating intervention entails whole-body or partial-body heat exposure. ...
Feet-heating and calf-heating have opposing effects on glucose tolerance and heart rate variability: a randomized, controlled, crossover trial
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Heat exposure’s effect on glucose tolerance depends on the amount of body exposed, likely relating to autonomic nervous system balance. We assessed how partial-body heat exposure at two different levels of the lower extremities affects glucose tolerance and autonomic nervous system balance, measured via heart rate variability. We hypothesized feet-heating would improve glucose tolerance without affecting heart rate variability, while calf-heating would worsen glucose tolerance and decrease heart rate variability compared to a thermoneutral control condition. In a randomized, controlled, crossover trial, healthy participants’ (N = 31, 23(3) years, 45% male) glucose tolerance was measured in (A) thermoneutral; (B) feet-heating; and (C) calf-heating conditions. Every 30 min for 2 h, blood glucose, heart rate, heart rate variability, tympanic temperature, thermal comfort scores, and blood pressure were measured. There were significant interactions between condition and time for blood glucose (F (4.6,72.6) = 2.6, p = 0.036), heart rate (F (3.4, 54.5) = 3.5, p = 0.017), heart rate variability (F (4.3,63.2) = 7.5, p < .0001), tympanic temperature (F (8, 268) = 2.4, p = 0.014), and thermal comfort scores (F (8, 248) = 22.1, p < 0.0001). Calf-heating increased 90 min glucose (+12 (95% confidence interval, CI: 3–21) mg/dL, p = 0.013) and decreased heart rate variability throughout (mean decrease: 13%–22%, p < 0.007), while feet-heating lowered 90 min glucose (−7 (95% CI: −16 to +1) mg/dL, p = 0.090) without affecting heart rate variability (p = 0.14–0.99). Blood pressure and body temperature were similar between conditions, but heart rate and thermal comfort scores increased with heating. Calf-heating worsens, while feet-heating may improve, glucose tolerance. Changes in heart rate variability coincided with changes in glucose tolerance despite unchanged body temperature. Whether heart rate variability can be used to monitor autonomic nervous system balance during heating to optimize its acute effect on glycemic indices should be further explored.
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... A study by Laukkanen et al. found that sauna bathing positively affects arterial stiffness, blood pressure, and some blood-based biomarkers for cardiovascular disease. 36 Sauna bathing has also been linked to improvement in pain from disorders like osteoarthritis. 37 However, individuals with SB should use caution, as autonomic dysfunction can impair heat regulation, and autonomic dysreflexia may cause dangerous spikes in blood pressure. ...
View
... In Korea, bathing has evolved through history from ritualistic and skincare practices to therapeutic uses, such as hot spring bathing, which emphasizes its health benefits [6] [7]. Recent studies have highlighted the positive effects of bathing on both physical and mental health, especially for those seeking stress relief and overall health improvement [8]. ...
View
... Sauna under the influence of high ambient temperature leads to the dilation of blood vessels and their relaxation, which leads to a decrease in blood pressure [10,11,12,13,14]. As a result, blood flow through the tissues increases, along with the nutrients and oxygen it contains. ...
The Impact of a Sauna on Post-Exercise Recovery
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Regeneration of the body after intense exercise is a key element necessary for the proper process of improving performance and achieving better results in strength training. One of the most important issues in any athlete is the uninterrupted continuation of training and the most optimal regeneration of tissues and the body, which is essential for further improvement of skills and development in a given sport. There are a number of methods to support the repair processes of tissues and help the body fight injuries and micro-injuries that occur during exercise and are an indispensable part of building strength and muscle mass. An example that has recently become very popular in the sports environment is the use of saunas characterized by thermal properties, through which it is possible to influence physiological processes that accelerate the return to form and achieve better results in sports competitions. This form not only helps tissue regeneration, but also relaxes and calms the body, which is stimulated during sports and requires calming afterwards.
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... Passive heat therapy, whereby individuals are exposed to acute bouts of heating for periods of ∼10-90 mins (Harwood et al. 2021;Pizzey et al. 2021), eliciting increases in heart rate and sweating, and a redistribution of blood from the core to the periphery (Laukkanen et al. 2018), is a nonpharmacological intervention that has been used for millennia for the treatment of a range of ailments and diseases (Papaioannou et al. 2016). More recently, passive heat therapy interventions have been utilised across a range of clinical (Akerman et al. 2019;Rodrigues et al. 2020) and rehabilitation settings (Brunt and Minson 2021) to promote physiological adaptations akin to those associated with exercise r Healthy persons with a mean age < 50 years. ...
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Ḥammāmtherapy: Integrating Tradition and Evidence in Therapeutic Practices
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Ḥammām therapy, a traditional bathing practice with historical roots in Roman and Islamic cultures, is designed to provide both physical and therapeutic benefits through a sequence of hot, warm, and cool rooms. Fundamental to the Unani medical system, it uses a series of hot, warm, and cool exposures to enhance circulation, aid in detoxification, and treat skin and musculoskeletal disorders. The therapeutic mechanism of the Ḥammāmis based on principles of balancing bodily humors and restoring health through Tarteeb (regulating moisture) and Taskhīn (heat therapy). Although the practice offers numerous health benefits, its use requires careful consideration of individual temperaments and medical conditions. This review examines the historical evolution, architectural structure, procedural aspects, and types of Ḥammāmbaths, including their specific health benefits & modern clinical studies validating its efficacy in conditions like metabolic syndrome, cardiovascular disorders, and post-stroke rehabilitation, emphasizing its relevance in contemporary integrative medicine.
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The objectives of this study were to investigate the effects of single session infrared sauna, traditional sauna, warm water immersion, and passive recovery from fatigue and muscle cell damage in athletes and nonathletes. Eight male badminton athletes and eight male nonathletes participated in this study. The study participants were treated with submaximal physical activity assessed by ergometer, then recovered with different modalities. Each treatment was separated by one week of a resting period through a randomized crossover design. The recovery modalities of infrared sauna (IRS) were 45±2°C, traditional sauna (TRS) 40±2°C, warm water immersion (WWI) 40±2°C, and passive recovery (PAS) for 20 minutes. Blood lactate, creatine kinase, blood glucose, heart rate, body temperature and level of pain were assessed, immediately after physical activity (pre), after recovery (post), and after 40 minutes of sitting (post-40min). Our findings indicated that the WWI and IRS were effective reducing fatigue in athletes and nonathletes. Moreover, PAS and TRS prevented muscle damage in nonathletes after 60 minutes of physical activity. All the thermal modalities decreased the BGL. The least amount of pain reported during the WWI modality, while the PAS modality tended to cause severe pain. Body temperature measurements were not significantly different among the modalities. According to our data, the WWI is more effective at increasing recovery and preventing muscle cell damage in athletes. Moreover, IRS and TRS are more effective for recovery in nonathletes. Further research needs to be conducted with different sports subjects, different types of exercise, different biomarkers, and physical performance tests. Keywords: infrared sauna; traditional sauna; warm water immersion; recovery; muscle cell damage
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Background: Sauna bathing is associated with reduced cardiovascular risk, but the mechanisms underlying this beneficial effect are not entirely understood. We aimed to assess the relationship between sauna bathing and risk of incident hypertension. Methods: Frequency of sauna bathing was ascertained using questionnaires in the Kuopio Ischemic Heart Disease Study, a prospective cohort study conducted in Eastern Finland that comprised a population-based sample of 1,621 men aged 42 to 60 years without hypertension at baseline. The incidence of hypertension was defined as a physician diagnosis of hypertension, systolic blood pressure (SBP) >140 mm Hg, diastolic blood pressure >90 mm Hg, or use of antihypertensive medication. Results: During a median follow-up of 24.7 years, 251 incident cases (15.5%) were recorded. In Cox regression analysis adjusted for baseline age, smoking, body mass index, and SBP; compared to participants reporting 1 sauna session per week, the hazard ratio for incident hypertension in participants reporting 2 to 3 sessions and 4 to 7 sessions was 0.76 (95% confidence interval: 0.57-1.02) and 0.54 (0.32-0.91), respectively. The corresponding hazard ratios were similar after further adjustment for glucose, creatinine, alcohol consumption, heart rate, family history of hypertension, socioeconomic status, and cardiorespiratory fitness: 0.83 (95% confidence interval: 0.59-1.18) and 0.53 (0.28-0.98), respectively. Conclusions: Regular sauna bathing is associated with reduced risk of hypertension, which may be a mechanism underlying the decreased cardiovascular risk associated with sauna use. Further epidemiological and experimental studies could help elucidate the effects of sauna bathing on cardiovascular function.
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Passive heat therapy improves cutaneous microvascular function in sedentary humans via improved nitric oxide-dependent dilation
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Methods: Eighteen young, sedentary, otherwise healthy subjects participated in 8 weeks of heat therapy (hot water immersion to maintain rectal temperature ≥38.5°C for 60min per session; N=9) or thermoneutral water immersion (sham; N=9), and participated in experiments before and after the 8-week intervention in which forearm cutaneous hyperemia to 39°C local heating was assessed at three microdialysis sites receiving 1) Lactated Ringer's (Control), 2) Nω-nitro-L-arginine (L-NNA, non-specific NO synthase inhibitor), and 3) Tempol, a superoxide dismutase mimetic. The arm used for microdialysis experiments remained out of the water at all times. Data are mean±S.E. cutaneous vascular conductance (CVC = laser Dopper flux/mean arterial pressure), presented as percent maximal CVC (%CVCmax). Results: Heat therapy increased local heating plateau from 42±6 to 53±6%CVCmax (p<0.001) and increased NO-dependent dilation (difference in plateau between Control and L-NNA sites) from 26±6 to 38±4%CVCmax (p<0.01), while no changes were observed in the sham group. When data were pooled across all subjects at 0wks, Tempol had no effect on the local heating response (p=0.53 vs. Control). There were no changes at the Tempol site across interventions (p=0.58). Conclusions: Passive heat therapy improves cutaneous microvascular function by improving NO-dependent dilation, which may have clinical implications.
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Passive heat therapy improves endothelial function, arterial stiffness, and blood pressure in sedentary humans
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Methods: Twenty young, sedentary subjects were assigned to participate in 8 weeks (4-5x/week) of heat therapy (N = 10; immersion in a 40.5°C bath sufficient to maintain rectal temperature ≥ 38.5°C for 60 min per session) or thermoneutral water immersion (N = 10; sham). Results: Eight weeks of heat therapy increased flow-mediated dilation from 5.6 ± 0.3% to 10.9 ± 1.0% (P < 0.01) and superficial femoral dynamic arterial compliance from 0.06 ± 0.01 to 0.09 ±0.01 mm(2) mmHg(-1) (P = 0.03), and reduced (i.e., improved) aortic pulse wave velocity from 7.1 ± 0.3 to 6.1 ± 0.3 m sec(-1) (P = 0.03), carotid intima media thickness from 0.43 ± 0.01 to 0.37 ± 0.01 mm (P < 0.001), and mean arterial blood pressure from 83 ± 1 to 78 ± 2 mmHg (P = 0.02). No changes were observed in the sham group or for carotid arterial compliance, superficial femoral intima media thickness or endothelium-independent dilation. Conclusions: Heat therapy improved endothelium-dependent dilation, arterial stiffness, intima media thickness, and blood pressure, indicating improved cardiovascular health. These data suggest heat therapy may provide a simple and effective tool for improving cardiovascular health in various populations. This article is protected by copyright. All rights reserved.
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Health effects and risks of sauna bathing
Article
Full-text available
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Objectives. To study physiological, therapeutic and adverse effects of sauna bathing with special reference to chronic diseases, medication and special situations (pregnancy, children). Study design. A literature review. Methods. Experiments of sauna bathing were accepted if they were conducted in a heated room with sufficient heat (80 to 90 degrees C), comfortable air humidity and adequate ventilation. The sauna exposure for five to 20 minutes was usually repeated one to three times. The experiments were either acute (one day), or conducted over a longer period (several months). Results. The research data retrieved were most often based on uncontrolled research designs with subjects accustomed to bathing since childhood. Sauna was well tolerated and posed no health risks to healthy people from childhood to old age. Baths did not appear to be particularly risky to patients with hypertension, coronary heart disease and congestive heart failure, when they were medicated and in a stable condition. Excepting toxemia cases, no adverse effects of bathing during pregnancy were found, and baths were not teratogenic. In musculoskeletal disorders, baths may relieve pain. Medication in general was of no concern during a bath, apart from antihypertensive medication, which may predispose to orthostatic hypotension after bathing. Conclusions. Further research is needed with sound experimental design, and with subjects not accustomed to sauna, before sauna bathing can routinely be used as a non-pharmacological treatment regimen in certain medical disorders to relieve symptoms and improve wellness.
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Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events
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Sauna bathing is a health habit associated with better hemodynamic function; however, the association of sauna bathing with cardiovascular and all-cause mortality is not known. To investigate the association of frequency and duration of sauna bathing with the risk of sudden cardiac death (SCD), fatal coronary heart disease (CHD), fatal cardiovascular disease (CVD), and all-cause mortality. We performed a prospective cohort study (Finnish Kuopio Ischemic Heart Disease Risk Factor Study) of a population-based sample of 2315 middle-aged (age range, 42-60 years) men from Eastern Finland. Baseline examinations were conducted from March 1, 1984, through December 31, 1989. Frequency and duration of sauna bathing assessed at baseline. During a median follow-up of 20.7 years (interquartile range, 18.1-22.6 years), 190 SCDs, 281 fatal CHDs, 407 fatal CVDs, and 929 all-cause mortality events occurred. A total of 601, 1513, and 201 participants reported having a sauna bathing session 1 time per week, 2 to 3 times per week, and 4 to 7 times per week, respectively. The numbers (percentages) of SCDs were 61 (10.1%), 119 (7.8%), and 10 (5.0%) in the 3 groups of the frequency of sauna bathing. The respective numbers were 89 (14.9%), 175 (11.5%), and 17 (8.5%) for fatal CHDs; 134 (22.3%), 249 (16.4%), and 24 (12.0%) for fatal CVDs; and 295 (49.1%), 572 (37.8%), and 62 (30.8%) for all-cause mortality events. After adjustment for CVD risk factors, compared with men with 1 sauna bathing session per week, the hazard ratio of SCD was 0.78 (95% CI, 0.57-1.07) for 2 to 3 sauna bathing sessions per week and 0.37 (95% CI, 0.18-0.75) for 4 to 7 sauna bathing sessions per week (P for trend = .005). Similar associations were found with CHD, CVD, and all-cause mortality (P for trend ≤.005). Compared with men having a sauna bathing session of less than 11 minutes, the adjusted hazard ratio for SCD was 0.93 (95% CI, 0.67-1.28) for sauna bathing sessions of 11 to 19 minutes and 0.48 (95% CI, 0.31-0.75) for sessions lasting more than 19 minutes (P for trend = .002); significant inverse associations were also observed for fatal CHDs and fatal CVDs (P for trend ≤.03) but not for all-cause mortality events. Increased frequency of sauna bathing is associated with a reduced risk of SCD, CHD, CVD, and all-cause mortality. Further studies are warranted to establish the potential mechanism that links sauna bathing and cardiovascular health.
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Effect of sauna-based heat acclimation on plasma volume and heart rate variability
Article
Full-text available
  • Nov 2014
We investigated the effect of post-exercise sauna bathing on plasma volume (PV) expansion and whether such responses can be tracked by changes in heart rate (HR)-based measures. Seven, well-trained male cyclists were monitored for 35 consecutive days (17 days baseline training, 10 days training plus sauna, 8 days training). Sauna exposure consisted of 30 min (87 °C, 11 % relative humidity) immediately following normal training. Capillary blood samples were collected while resting seated to assess PV changes. HR (HRwake) and vagal-related HR variability (natural logarithm of square root mean squared differences of successive R-R intervals, ln rMSSDwake) were assessed daily upon waking. A sub-maximal cycle test (5 min at 125 W) was performed on days 1, 8, 15, 22, 25, 29, and 35 and HR recovery (HRR60s) and ln rMSSDpostex were assessed post-exercise. Effects were examined using magnitude-based inferences. Compared with baseline, sauna resulted in: (1) peak PV expansion after four exposures with a likely large increase [+17.8 % (90 % confidence limits, 7.4; 29.2)]; (2) reduction of HRwake by a trivial-to-moderate amount [-10.2 % (-15.9; -4.0)]; (3) trivial-to-small changes for ln rMSSDwake [4.3 % (1.9; 6.8)] and ln rMSSDpostex [-2.4 % (-9.1; 4.9)]; and (4) a likely moderate decrease in HRR60s [-15.6 % (-30.9; 3.0)]. Correlations between individual changes in PV and HR measures were all unclear. Sauna bathing following normal training largely expanded PV in well-trained cyclists after just four exposures. The utility of HR and HRV indices for tracking changes in PV was uncertain. Future studies will clarify mechanisms and performance benefits of post-training sauna bathing.
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Lower-limb hot-water immersion acutely induces beneficial hemodynamic and cardiovascular responses in peripheral arterial disease and healthy, elderly controls
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  • Dec 2016
  • AM J PHYSIOL-REG I
Passive heat induces beneficial perfusion profiles, provides substantive cardiovascular strain and reduces blood pressure, thereby holding potential for healthy and cardiovascular disease populations. The aim of this study was to assess acute responses to passive heat via lower-limb hot-water immersion in patients with peripheral arterial disease (PAD) and healthy, elderly controls. Eleven patients with PAD (age 71±6 y, 7 male) and ten Controls (age 72±7 y, 8 male) underwent hot-water immersion (30 min waist-level immersion in 42.1±0.6°C water). Before, during and following immersion, brachial and popliteal artery diameter, blood flow and shear stress were assessed using duplex ultrasound. Lower-limb perfusion was measured also using venous occlusion plethysmography and near-infrared spectroscopy. During immersion, shear rate increased (p<0.0001) comparably between groups in the popliteal artery (Controls: +183±26%; PAD: +258±54%) and brachial artery (Controls: +117±24%; PAD: +107±32%). Lower-limb blood flow increased significantly in both groups, as measured from duplex ultrasound (>200%), plethysmography (>100%) and spectroscopy, while central and peripheral pulse wave velocity decreased in both groups. Mean arterial blood pressure was reduced by 22±9 mmHg (main effect p<0.0001, interaction p=0.60) during immersion, and remained 7±7 mmHg lower 3 h afterward. In PAD, popliteal shear profiles and claudication both compared favourably with those measured immediately following symptom-limited walking. A 30-min hot-water immersion is a practical means of delivering heat therapy to PAD patients and healthy, elderly individuals to induce appreciable systemic (chronotropic and blood pressure lowering) and hemodynamic (upper and lower-limb perfusion and shear rate increases) responses.
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Sauna bathing is inversely associated with dementia and Alzheimer's disease in middle-aged Finnish men
Article
  • Dec 2016
  • AGE AGEING
Background: there are no previous studies linking repeated heat exposure of sauna and the risk of memory diseases. We aimed to investigate whether frequency of sauna bathing is associated with risk of dementia and Alzheimer's disease. Setting: prospective population-based study. Methods: the frequency of sauna bathing was assessed at baseline in the Kuopio Ischaemic Heart Disease population-based prospective cohort study of 2,315 apparently healthy men aged 42-60 years at baseline, with baseline examinations conducted between 1984 and 1989. Hazard ratios (HRs) with 95% confidence intervals (CIs) for dementia and Alzheimer's disease were ascertained using Cox-regression modelling with adjustment for potential confounders. Results: during a median follow-up of 20.7 (interquartile range 18.1-22.6) years, a total of 204 and 123 diagnosed cases of dementia and Alzheimer's disease were respectively recorded. In analysis adjusted for age, alcohol consumption, body mass index, systolic blood pressure, smoking status, Type 2 diabetes, previous myocardial infarction, resting heart rate and serum low-density lipoprotein cholesterol, compared with men with only 1 sauna bathing session per week, the HR for dementia was 0.78 (95% CI: 0.57-1.06) for 2-3 sauna bathing sessions per week and 0.34 (95% CI: 0.16-0.71) for 4-7 sauna bathing sessions per week. The corresponding HRs for Alzheimer's disease were 0.80 (95% CI: 0.53-1.20) and 0.35 (95% CI: 0.14-0.90). Conclusion: in this male population, moderate to high frequency of sauna bathing was associated with lowered risks of dementia and Alzheimer's disease. Further studies are warranted to establish the potential mechanisms linking sauna bathing and memory diseases.
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Health Benefits of Sauna Bathing
Article
  • Feb 2015
Often I have advised a patient who was considering an unnecessary test, such as a coronary artery calcium test or carotid ultrasonography from a mobile van, to forgo that test and instead spend the money on something that he or she would actually enjoy, such as a massage or spa treatment. In this issue, Laukkanen et al¹ present data indicating that my advice would not only help my patients feel good but would also, if they chose to regularly use a sauna bath, help them live longer. Analyzing data from the Finnish Kuopio Ischemic Heart Disease Study, the authors found that men who took more frequent saunas (4-7 times per week) actually live longer than once-per-week users. Although we do not know why the men who took saunas more frequently had greater longevity (whether it is the time spent in the hot room, the relaxation time, the leisure of a life that allows for more relaxation time, or the camaraderie of the sauna), clearly time spent in the sauna is time well spent.
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Comparison of the Microlife Blood Pressure Monitor With the Omron Blood Pressure Monitor for Detecting Atrial Fibrillation
Article
  • Oct 2014
  • AM J CARDIOL
Screening for atrial fibrillation (AF) by assessing the pulse is recommended in high risk patients. Some clinical trials demonstrated that the Microlife blood pressure monitor (BPM) with AF detection is more accurate than pulse palpation. This led to a change in practice guidelines in the UK where AF screening with the Microlife device is recommended instead of pulse palpation. Many BPMs have irregular heart beat detection (IHD) but they have not been shown to detect AF reliably. Recently, one study, in a highly select population, suggested that the Omron BPM with IHD has a higher sensitivity for AF than the Microlife BPM. We compared the Microlife and the Omron BPMs to ECG readings for AF detection in general cardiology patients. Inclusion criteria were age >50 without a pacemaker or defibrillator. A total of 199 subjects were enrolled, 30 with AF. Each subject had a 12-lead ECG, one Omron BPM reading and three Microlife BPM readings as per device instructions. The Omron device had a sensitivity of 30% (95% confidence interval (CI) 15.4%-49.1%) with the sensitivity for the first Microlife reading of 97% (95% CI 81.4%-100%) and the Microlife readings using the majority rule (AF positive if at least two out of three individual readings positive for AF) of 100% (95% CI 85.9%-100%). Specificity for the Omron device was 97% (95% CI 92.5%-99.2%) and for the first Microlife reading of 90% (95% CI 83.8%-94.2%%) and for the majority rule Microlife device 92% (95% CI 86.2%-95.7%) (p<.0001). The specificity of both devices is acceptable but only the Microlife BPM has a sensitivity value that is high enough to be used for AF screening in clinical practice.
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