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Effects of Exercise Training with a Sauna Suit on Cardiovascular Health: a Proof-of-Concept Study

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Abstract Introduction: Cardiovascular disease (CVD) is the leading cause of death worldwide, accounting for 17.3 million deaths per annum, a figure that is projected to grow to more than 23.6 million by 2030. It has been estimated that 80% of premature heart disease can be prevented through positive modification of CVD risk factors. It has been demonstrated that systemic thermal therapy by regular administration of heat through a variety of methodologies, such as sauna or taking a warm bath, can induce a number of advantageous responses in terms of cardiovascular health. However, no studies have investigated the effects of exercise training with a sauna suit, a practical and portable alternative to other thermal treatments, on cardiometabolic risk factors. The purpose of this study was to determine the effectiveness of exercise training with a sauna suit at positively modifying cardiometabolic risk factors. Methods: Twelve men (mean ± SD: age, height, weight, percentage body fat, and VO2max = 25.3 ± 7.3 yr, 179.6 ± 5.7 cm, 78.6 ± 7.6 kg, 14.6 ± 3.3 %, and 50.4 ± 8.8 mL/kg/min, respectively) completed a 6wk exercise training program (30min sessions performed 5 days/wk at a moderate-intensity of 55-60% heart rate reserve) while wearing a sauna suit. Cardiometabolic risk factors were measured at baseline and post-program. Results: After 6wk of exercise training with a sauna suit there were significant (p < 0.05) improvements in the following cardiometabolic risk factors: percentage body fat (relative Δ -1.5%), systolic (relative Δ -1.4%) and diastolic (relative Δ -3.1%) blood pressure, triglycerides (relative Δ -15.5%), HDL cholesterol (relative Δ +6.4%), and maximal oxygen uptake (relative Δ +8.5%). Conclusions: Findings from the present study support the feasibility of exercise training with a sauna suit to improve cardiovascular health. Indeed, the present study demonstrated that regular moderate-intensity exercise training with a sauna suit elicited improvements in cardiorespiratory fitness and positive modification to several key CVD risk factors. Key Words: Heart Disease, Hyperthermic Conditioning, Physical Activity, Prevention
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[Year]
1
Van De Velde et al. (2016) Int J Res Ex Phys. 11(1):1-10.
Sponsored by:
Exercise and Sport Science Program
Western State Colorado University
Effects of Exercise Training with a Sauna Suit on Cardiovascular
Health: a Proof-of-Concept Study
Samuel S. Van de Velde1, Isaiah A. St. Pierre1, Bryant R. Byrd1, Jennifer S. Fargo1, Lexie B. Loring1, Lance C. Dalleck1
1High Altitude Exercise Physiology Program, Western State Colorado University, Gunnison, CO, USA
Abstract
Introduction: Cardiovascular disease (CVD) is the leading cause of death worldwide, accounting for
17.3 million deaths per annum, a figure that is projected to grow to more than 23.6 million by 2030. It
has been estimated that 80% of premature heart disease can be prevented through positive
modification of CVD risk factors. It has been demonstrated that systemic thermal therapy by regular
administration of heat through a variety of methodologies, such as sauna or taking a warm bath, can
induce a number of advantageous responses in terms of cardiovascular health. However, no studies
have investigated the effects of exercise training with a sauna suit, a practical and portable alternative
to other thermal treatments, on cardiometabolic risk factors. The purpose of this study was to
determine the effectiveness of exercise training with a sauna suit at positively modifying
cardiometabolic risk factors. Methods: Twelve men (mean ± SD: age, height, weight, percentage body
fat, and VO2max = 25.3 ± 7.3 yr, 179.6 ± 5.7 cm, 78.6 ± 7.6 kg, 14.6 ± 3.3 %, and 50.4 ± 8.8 mL/kg/min,
respectively) completed a 6wk exercise training program (30min sessions performed 5 days/wk at a
moderate-intensity of 55-60% heart rate reserve) while wearing a sauna suit. Cardiometabolic risk
factors were measured at baseline and post-program. Results: After 6wk of exercise training with a
sauna suit there were significant (p < 0.05) improvements in the following cardiometabolic risk factors:
percentage body fat (relative Δ -1.5%), systolic (relative Δ -1.4%) and diastolic (relative Δ -3.1%) blood
pressure, triglycerides (relative Δ -15.5%), HDL cholesterol (relative Δ +6.4%), and maximal oxygen
uptake (relative Δ +8.5%). Conclusions: Findings from the present study support the feasibility of
exercise training with a sauna suit to improve cardiovascular health. Indeed, the present study
demonstrated that regular moderate-intensity exercise training with a sauna suit elicited
improvements in cardiorespiratory fitness and positive modification to several key CVD risk factors.
Key Words: Heart Disease, Hyperthermic Conditioning, Physical Activity, Prevention
[Year]
2
Van De Velde et al. (2016) Int J Res Ex Phys. 11(1):1-10.
Sponsored by:
Exercise and Sport Science Program
Western State Colorado University
Introduction
Cardiovascular disease (CVD) is the leading
cause of death worldwide, accounting for
17.3 million deaths per annum, a figure that
is projected to grow to more than 23.6
million by 20301. It has been estimated that
80% of premature heart disease can be
prevented through positive modification of
CVD risk factors2. In particular, regular
physical activity has been shown to confer a
myriad of health benefits, including the
prevention of numerous CVD risk factors
such as hypertension, obesity, Type 2
diabetes, and dyslipidemia3. Moreover,
contemporary evidence has demonstrated
that systemic thermal therapy by regular
administration of heat through a variety of
methodologies (e.g., sauna and hot tub) can
also induce a number of advantageous
responses in terms of cardiovascular health.
Indeed, chronic exposure to heat stress (in
the form of sauna bathing) has been
reported to be associated with a reduced
risk of cardiovascular disease and mortality
from all-causes4. Additionally, Krause and
colleagues (2015) reported that
heat therapy reduces fasting glycemia,
glycated hemoglobin, body weight, and
adiposity5.
There is also evidence that exercise in
conjunction with heat therapy provides
cardiovascular health benefits. For instance,
it has been demonstrated that 3 weeks of
post-exercise sauna bathing elicits an
improvement in cardiorespiratory fitness,
most likely due to an increase in plasma
volume6. However, to our knowledge, no
studies have investigated the effects of
exercise training with a sauna suit on
cardiometabolic risk factors. It is plausible
that exercise training with a sauna suit may
provide fitness enthusiasts with a more
practical and portable heat therapy
alternative when compared to other
thermal treatments. The purpose of this
proof-of-concept’ study was to determine
the potential effectiveness of exercise
training with a sauna suit at positively
modifying cardiometabolic risk factors. It
was hypothesized that exercise training
with a sauna suit would elicit improvements
in cardiovascular health.
Methods
Participants
12 healthy and physically active young-to-
middle age adults (18 to 44 years of age)
consented to participate in the study.
Participants were eligible for inclusion into
the study if they were low risk and
physically active as defined by the American
College of Sports Medicine7. This study was
approved by the Human Research
Committee at Western State Colorado
University.
Experimental Design
At baseline and post-program,
measurements were obtained for all
primary outcome variables presented in
Figure 1. All baseline and post-program
measurements were obtained from each
participant at similar times of the day 2
hrs).
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Van De Velde et al. (2016) Int J Res Ex Phys. 11(1):1-10.
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Exercise and Sport Science Program
Western State Colorado University
All participants completed a standardized
6wk exercise training program that
consisted of 30min of exercise performed
on a cycle ergometer at moderate-intensity
(55-60% heart rate reserve HRR) for 5
days/wk. All exercise sessions were directly
supervised, completed while wearing a
sauna suit (Kutting Weight, LLC., Los
Angeles, CA), and performed in controlled
environmental conditions (19°C). The
intervention was based on pilot testing
from four experimental trials: (1) 30
minutes of moderate-intensity exercise (55-
60% HRR) with a sauna suit, (2) 20 minutes
of vigorous-intensity exercise (75-80% HRR)
with a sauna suit, (3) 30 minutes of
moderate-intensity exercise (55-60% HRR)
without a sauna suit (i.e., control), and (4)
20 minutes vigorous-intensity exercise (75-
80% HRR) without a sauna suit (i.e.,
control). In the moderate-intensity exercise
trial condition there was a ~45% greater
excess post-exercise oxygen consumption
(EPOC) with the sauna suit (70 calories) vs.
control condition (45 calories). Likewise, in
the vigorous-intensity exercise trial
condition there was a ~20% greater EPOC
with the sauna suit (72 calories) vs. control
condition (88 calories).The 150 min/wk
exercise training with the sauna suit were
substituted for pre-existing exercise training
for each participant in a manner that
resulted in overall exercise training volume
and intensity remaining unchanged
throughout the 6wk intervention period.
This experimental design permitted
examination of the effectiveness of exercise
training with a sauna suit at positively
modifying cardiometabolic risk factors.
Participants were strictly instructed to
maintain their other exercise training and
dietary regimens.
Figure 1. Experimental design for cardiometabolic responses to exercise training with a sauna suit.
[Year]
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Van De Velde et al. (2016) Int J Res Ex Phys. 11(1):1-10.
Sponsored by:
Exercise and Sport Science Program
Western State Colorado University
Protocols
Physical and physiological measurements
All physical measurements were obtained
using standardised guidelines7. Briefly,
participants were weighed to the nearest
0.1 kg on a medical grade scale and
measured for height to the nearest 0.5 cm
using a stadiometer. Percent body fat was
determined via hydrostatic weighing. Waist
circumference measurements were
obtained using a cloth tape measure with a
spring loaded-handle (Creative Health
Products, Ann Arbor, MI). A horizontal
measurement was taken at the narrowest
point of the torso (below the xiphoid
process and above the umbilicus). These
measurements were taken until two were
within 0.5 mm of each other.
Fasting blood lipid and glucose
measurement
All fasting lipid and blood glucose analyses
were collected and performed at room
temperature. Participants’ hands were
washed with soap and rinsed thoroughly
with water, then cleaned with alcohol
swabs and allowed to dry. Skin was
punctured using lancets and a fingerstick
sample was collected into heparin-coated
40 l capillary tube. Blood was allowed to
flow freely from the fingerstick into the
capillary tube without milking of the finger.
Samples were then dispensed immediately
onto commercially available test cassettes
for analysis in a Cholestech LDX System
(Alere Inc., Waltham, MA) according to
strict standardized operating procedures.
The LDX Cholestech measured total
cholesterol, high density lipoprotein (HDL)
cholesterol, low density lipoprotein (LDL)
cholesterol, triglycerides, and blood glucose
in fingerstick blood. A daily optics check
was performed on the LDX Cholestech
analyzer used for the study.
Resting heart rate and blood pressure
measurements
The procedures for assessment of resting
HR and blood pressure outlined elsewhere
were followed7. Briefly, participants were
seated quietly for 5 minutes in a chair with
a back support with feet on the floor and
arm supported at heart level. Resting HR
was obtained by palpating the radial artery
for pulse for 60 seconds. The left arm
brachial artery blood pressure was
measured using a sphygmomanometer in
duplicate and separated by 1 minute. The
mean of the two measurements was
reported for baseline and post-program
values.
Maximal exercise test
Participants completed incremental
maximal exercise on a cycle ergometer
(Viasprint 150P; Sensormedics Corp., Palm
Springs, CA) at baseline and post-program
during which gas exchange data, power
output, and HR were assessed. Participants
completed 2 minutes of pedaling at 50
Watts as a warm up. Workload was then
increased in a steplike manner equal to 8-
12 Watts/20 seconds to elicit volitional
fatigue in approximately 10-12 minutes. The
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Van De Velde et al. (2016) Int J Res Ex Phys. 11(1):1-10.
Sponsored by:
Exercise and Sport Science Program
Western State Colorado University
specific workload increment for each test
was matched to participant fitness level.
Pedal cadence was maintained at 70-90
rev/min, with volitional fatigue representing
a failure to sustain pedal cadence greater
than 40 rev/min. Workload at volitional
fatigue was recorded as peak power output.
Gas exchange and data analysis
Prior to each maximal exercise test, the
metabolic cart (TrueOne 2400, Parvo
Medics, Sandy, UT) was calibrated with
gases of known concentrations (16.02% O2,
4.00% CO2) and with room air (20.93% O2
and 0.03% CO2) as per the manufacture
guidelines. Calibration of the
pneumotachometer was done via a 3 Litre
calibration syringe (Hans-Rudolph, Kansas
City, MO). Throughout the maximal exercise
test continuous pulmonary gas exchange
data was obtained. In order to determine
VO2max from the maximal exercise test, the
final 15 seconds of data were averaged
constituting the final data point. The next
closest data point was calculated by
averaging the data during the 15 seconds
prior to the final 15 seconds. The VO2max
was represented by the mean of the 2
processed data points provided a plateau
was exhibited (VO2 < 150 mL/min)8.
Determination of both the first ventilatory
threshold (VT1) and second ventilatory
threshold (VT2) were made by visual
inspection of graphs of time plotted against
each relevant respiratory variable
(according to 15 second time-averaging)9.
The criteria for VT1 was an increase in
VE/VO2 with no concurrent increase in
VE/VCO2 and departure from the linearity
of VE. The criteria for VT2 was a
simultaneous increase in both VE/VO2 and
VE/VCO2. Overall ventilatory threshold was
recorded as the mean of VT1 and VT2. All
assessments were done by two experienced
exercise physiologists. In the event of
conflicting results, the original assessments
were reevaluated and collectively a
consensus was agreed upon.
Statistical analyses
All analyses were performed using SPSS
Version 22.0 (Chicago, IL) and GraphPad
Prism 6.0. (San Diego, CA). Measures of
centrality and spread are presented as
mean SD and percentage (%) change from
baseline to post-program. Primary outcome
measures were the change in
cardiometabolic risk factors, including
VO2max, systolic blood pressure, diastolic
blood pressure, weight, waist
circumference, body composition, blood
lipids, and blood glucose. Paired t-tests
were used to compare the mean
cardiometabolic risk factors values between
baseline and post-program. The probability
of making a Type I error was set at p .05
for all statistical analyses.
[Year]
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Van De Velde et al. (2016) Int J Res Ex Phys. 11(1):1-10.
Sponsored by:
Exercise and Sport Science Program
Western State Colorado University
Results
The intervention was well tolerated for all
12 participants. Each of the 12 participants
completed all 30 scheduled exercise
training sessions. Moreover, across 360
total exercise sessions spanning a total of
180 hours training in the sauna suit, there
were no adverse events experienced across
all exercise training sessions and all
physiological responses remained within
normal ranges.
Cardiometabolic outcomes
The physical and cardiometabolic
characteristics for participants at baseline
and 6 weeks post-training are shown in
Table 1. After 6wk, there were significant
improvements (p < 0.05) in resting heart
rate, resting systolic and diastolic blood
pressure, body composition, HDL
cholesterol, and triglycerides. In contrast,
body weight, waist circumference, total
cholesterol, LDL cholesterol, and blood
glucose were relatively unchanged (p >
0.05) following 6wk of exercise training.
Maximal exercise test outcomes
The maximal exercise test outcomes for
participants at baseline and 6wk post-
training are shown in Table 2. After 6wk,
there were significant improvements
(p < 0.05) in peak power output, ventilatory
threshold, and VO2max.
Table 1. Physical and cardiometabolic characteristics at baseline and 6wk. (Values are mean SD).
Characteristic
Baseline
6wk
relative % change
Age (yr)
25.3 7.3
____
____
Height (cm)
179.6 5.7
____
____
Body weight (kg)
78.6 7.6
78.2 7.0
-0.5%
Waist circumference (cm)
81.4 5.7
80.8 5.6
-0.7%
Body fat (%)
14.6 3.3
13.1 2.9*
-10.3%
Resting HR (b/min)
60.6 9.2
57.4 9.3*
-5.3%
Systolic blood pressure (mmHg)
118.8 3.0
117.1 2.6*
-1.4%
Diastolic blood pressure (mmHg)
79.7 4.8
77.2 5.0*
-3.1%
Total cholesterol (mg/dL)
177.0 19.2
171.3 14.1
-3.2%
HDL cholesterol (mg/dL)
54.8 14.3
58.3 11.9*
+6.4%
LDL cholesterol (mg/dL)
96.7 18.0
94.5 16.8
-2.3%
Triglycerides (mg/dL)
106.3 58.1
89.8 52.4*
-15.5%
Blood Glucose (mg/dL)
84.3 6.0
83.0 6.4
-1.5%
* Within-group change is significantly different from baseline, p < 0.05.
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Van De Velde et al. (2016) Int J Res Ex Phys. 11(1):1-10.
Sponsored by:
Exercise and Sport Science Program
Western State Colorado University
Table 2. Performance variables at baseline and 6wk. (Values are mean SD).
Variable
Baseline
6wk
relative % change
Peak power output (Watts)
357.8 66.6
371.3 66.3*
+3.8%
Ventilatory threshold (%)
66.9 7.7
72.5 7.1*
+8.4%
VO2max (mL/kg/min)
50.4 8.8
54.7 8.3*
+8.5%
* Within-group change is significantly different from baseline, p < 0.05.
Discussion
The primary finding of the present study is
that a short-term training program
consisting of moderate-intensity exercise in
conjunction with thermal treatment (i.e.,
wearing a sauna suit) augmented
cardiovascular health. Indeed, classical CVD
risk factors, including body composition,
HDL cholesterol, and triglycerides were all
significantly improved post-intervention.
Moreover, cardiorespiratory fitness, an
independent and powerful predictor of CVD
risk and premature mortality, was also
increased. Although administration of heat
through a variety of methodologies,
including sauna and hot tub, has been
previously demonstrated to enhance
cardiovascular health, to our knowledge,
the physiological responses to exercise
training with a sauna suit has not been
scientifically explored. As such, the results
of this novel proof-of-concept study are
encouraging and support use of a practical
and portable sauna suit as a form of
thermal treatment to enhance exercise-
related health outcomes and prevent CVD.
Cardiorespiratory response to exercise
training with a sauna suit
We found that 6wk of moderate-intensity
exercise training with a sauna suit increased
VO2max by an absolute amount of 4.3
mL/kg/min. In terms of metabolic
equivalents (METs) this equates to ~1.2
METs (3.5 mL/kg/min = 1.0 METs). This
magnitude improvement in VO2max is
comparable to that reported elsewhere in
the literature for more high-intensity
interval training (HIT). For example,
Helgerud and colleagues reported a 4.9
mL/kg/min increase in VO2max in a cohort
of moderately trained men following 8
weeks of HIT consisting of 4 x 4 minutes of
running at 90-95% maximal HR10. In the
past decade being aerobically or physically
“unfit” has garnered considerable attention
as an independent and powerful predictor
of an increased CVD risk and premature
mortality11. For example, a meta-analysis by
Williams12 showed that there was an 40%
increase in relative risk for CVD in adults in
the lowest quartile of aerobic fitness when
compared to the highest quartile, while
more recently Blair13 proposed that a low
level of aerobic fitness accounted for more
overall deaths compared to those
attributable to traditional CVD risk factors,
such as obesity, smoking, hypertension,
high cholesterol, and diabetes. Accordingly,
the results from this current study have
novel public health relevance, as a large
number of adults fall into defined low
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Van De Velde et al. (2016) Int J Res Ex Phys. 11(1):1-10.
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Exercise and Sport Science Program
Western State Colorado University
aerobic fitness categories14. Overall, the
improvement in VO2max (i.e., 1.2 METs) in
the present study likely has potentially
important long-term prevention
implications as a recent work has reported
that a 1 MET increase in VO2max was
associated with an 18% reduction in CVD-
related mortality15.
Cardiometabolic responses to exercise
training with a sauna suit
The blood lipid changes in the present study
are also comparable with those typically
reported in the literature following aerobic-
based exercise training. For instance, in a
review on the lipid and lipoprotein
adaptations to exercise, Durstine et al.
(2001) reported that 15 to 20 miles per
week of brisk walking or jogging was
associated with an average 2 to 3 mg/dL
increase in HDL cholesterol and 8 to 20
mg/dL decrease in triglycerides16. Our
findings of a 3.5 mg/dL improvement in HDL
cholesterol and 16.5 mg/dL reduction in
triglycerides are in close agreement with
those previously reported. Moreover, low
HDL cholesterol values represent a strong
modifiable and independent risk factor for
CVD17. Indeed, it has been estimated that
for every 1 mg/dL increase in HDL
cholesterol, the risk for a coronary heart
disease (CHD) event is reduced by 2% in
men18. Our data therefore suggests men
reduced their risk for a CHD event by ~7%
with substitution of 150 minutes per week
of exercise with a sauna suit to their overall
training regimen.
In a previous meta-analysis19, it was
reported that aerobic exercise training will
elicit average reductions in resting systolic
and diastolic blood pressure of 3 to 4 mmHg
and 2 to 3 mmHg, respectively. The
decreased resting systolic blood pressure (-
1.7 mmHg) and diastolic blood preeure (-2.5
mmHg) measurements observed in the
present study are consistent in magnitude
with those previously reported in the
literature. Next to low cardiorespiratory
fitness, hypertension has been implicated in
the second highest number of overall
deaths according to one study13. Although
the reductions in systolic and diastolic
blood pressure in the present study appear
rather modest in nature, the reality is these
training adaptations represent a positive
impact on overall CVD risk as it has been
demonstrated that blood pressure
decreases of as little as 2 mmHg are
associated with a 6% decrease in stroke
mortality and a 4% decrease in coronary
artery disease20.
Heat treatment and cardiovascular health:
possible mechanisms
The array of cardiovascular health benefits
elicited by exercise training with a sauna
suit are likely underpinned by a number of
plausible mechanisms. For example, it has
been demonstrated that heat therapy leads
to elevations in nitric oxide a potent
vasodilator5. Ultimately, increased
concentrations in nitric oxide can lead to
improvements in insulin signaling, body
composition, and inflammation5.
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Van De Velde et al. (2016) Int J Res Ex Phys. 11(1):1-10.
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Exercise and Sport Science Program
Western State Colorado University
Additionally, increased plasma volume is a
hallmark adaptation to chronic heat
exposure6. In turn, it is well known that
increased plasma volume is an important
factor mediating improvements in VO2max.
Methodological Considerations
Possible limitations to the present study
merit discussion. First, the present study did
not include a control group. Therefore, it
cannot be entirely excluded that similar
results could be achieved with an exercise
alone intervention of equal 6wk duration.
Nevertheless, the fact that the 150 min/wk
of exercise training with the sauna suit were
substituted for pre-existing exercise training
for each participant in a manner that
resulted in overall exercise training volume
and intensity remaining unchanged
throughout the 6wk intervention
strengthens the likelihood that it was
specifically exercise training with a sauna
suit that elicited positive modifications in
cardiorespiratory fitness and
cardiometabolic risk factors. Additionally,
the chronic physiological responses to
exercise training with a sauna suit may be
more pronounced with a longer training
period beyond the 6wk duration of the
present study.
Conclusions
The main findings of the current study
indicate that exercise training with a sauna
suit confers numerous cardiovascular health
benefits. Previous research has shown that
chronic exposure to heat stress (in the form
of sauna bathing) is linked with reduced risk
for both cardiovascular disease and
mortality from all-causes4. The favorable
changes in various cardiometabolic risk
factors (body composition, blood pressure,
and lipid profile) and cardiorespiratory
fitness observed in the present study
following exercise training with the sauna
suit provide a likely mechanistic explanation
for why chronic exposure to heat stress
improves long-term health. Overall,
exercise training completed while wearing a
sauna suit provides individuals with a
practical and safe heat treatment
alternative to achieve important health and
fitness goals.
Practical Application
To our knowledge, this proof-of-
concept’ study is the first to investigate
the effects of exercise training with a
sauna suit on cardiovascular health.
The present study provides preliminary
evidence that supports use of a
practical and portable sauna suit as a
form of thermal treatment to enhance
exercise-related health outcomes and
prevent CVD.
Overall, these findings are important for
exercise physiologists, fitness
professionals, and others who design
exercise programs and promote
physical activity in the adult population.
Competing interests
This investigation was supported financially by
Kutting Weight, LLC. Kutting Weight, LLC was
not involved in development of the study
design, data collection and analysis, or
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Van De Velde et al. (2016) Int J Res Ex Phys. 11(1):1-10.
Sponsored by:
Exercise and Sport Science Program
Western State Colorado University
preparation of the manuscript. There are no
other potential conflicts of interest related to
this article.
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... A proposed method for inducing (should access to an environmental chamber not be possible), or enhancing the efficiency (by accelerating the attainment of necessary physiological stimuli for adaptation) of HA is the wearing of clothing/garments which restrict heat loss during exercise [28]. Wearing garments that inhibit evaporative heat loss such as vinyl suits, or by overdressing in regular clothing, attenuates the rate of heat dissipation in temperate training environments [28][29][30][31]. Inhibited heat loss results in a greater rate of heat storage during exercise and ultimately, elevations in physiological strain [29]. ...
... Whilst the influence of restricted heat loss clothing during exercise in occupational contexts have been described [53,54], the use of sauna suits during training for performance has been less robustly investigated. Emerging data has reported the benefit of wearing a sauna suit during a 6-week training programme in temperate conditions (30-min sessions, 5 days per week) [31]. Physiological adaptations included; reductions in resting HR (¡4 b.min ¡1 ), systolic (¡2 mmHg) and diastolic blood pressure (¡3 mmHg), and, an improved anaerobic threshold (+5.6% of V̇O 2max ) and V̇O 2max (+4.3 mL.kg ¡1 .min ...
... Physiological adaptations included; reductions in resting HR (¡4 b.min ¡1 ), systolic (¡2 mmHg) and diastolic blood pressure (¡3 mmHg), and, an improved anaerobic threshold (+5.6% of V̇O 2max ) and V̇O 2max (+4.3 mL.kg ¡1 .min ¡1 ) [31]. These enhancements appear congruous with the magnitudes of adaptation associated with HA [26], albeit they were achieved over a considerably longer period than most HA protocols and did not include a comparable control group. ...
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The aim of this experiment was to quantify physiological and perceptual responses to exercise with and without restrictive heat loss attire in hot and temperate conditions. Ten moderately-trained individuals (mass; 69.44±7.50 kg, body fat; 19.7±7.6%) cycled for 30-mins (15-mins at 2 W.kg⁻¹ then 15-mins at 1 W.kg⁻¹) under four experimental conditions; temperate (TEMP, 22°C/45%), hot (HOT, 45°C/20%) and, temperate (TEMPSUIT, 22°C/45%) and hot (HOTSUIT, 45°C/20%) whilst wearing an upper-body “sauna suit”. Core temperature changes were higher (P<0.05) in TEMPSUIT (+1.7±0.4°C.hr⁻¹), HOT (+1.9±0.5°C.hr⁻¹) and HOTSUIT (+2.3±0.5°C.hr⁻¹) than TEMP (+1.3±0.3°C.hr⁻¹). Skin temperature was higher (P<0.05) in HOT (36.53±0.93°C) and HOTSUIT (37.68±0.68°C) than TEMP (33.50±1.77°C) and TEMPSUIT (33.41±0.70°C). Sweat rate was greater (P<0.05) in TEMPSUIT (0.89±0.24 L.hr⁻¹), HOT (1.14±0.48 L.hr⁻¹) and HOTSUIT (1.51±0.52 L.hr⁻¹) than TEMP (0.56±0.27 L.hr⁻¹). Peak heart rate was higher (P<0.05) in TEMPSUIT (155±23 b.min⁻¹), HOT (163±18 b.min⁻¹) and HOTSUIT (171±18 b.min⁻¹) than TEMP (151±20 b.min⁻¹). Thermal sensation and perceived exertion were greater (P<0.05) in TEMPSUIT (5.8±0.5 and 14±1), HOT (6.4±0.5 and 15±1) and HOTSUIT (7.1±0.5 and 16±1) than TEMP (5.3±0.5 and 14±1). Exercising in an upper-body sauna suit within temperate conditions induces a greater physiological strain and evokes larger sweat losses compared to exercising in the same conditions, without restricting heat loss. In hot conditions, wearing a sauna suit increases physiological and perceptual strain further, which may accelerate the stimuli for heat adaptation and improve HA efficiency.
... Recent research has investigated the effects of exercise training in a sauna suit and the impact it has on EPOC and other health parameters. A study by Van de Velde et al. 20 used 12 well-trained participants in a sixweek training program while wearing a sauna suit. The study found significant improvements in cardiometabolic risk factors such as body fat percentage, systolic and diastolic blood pressure, triglycerides, HDL cholesterol, and maximal oxygen uptake. ...
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Purpose: Worldwide, the prevalence of overweight and obesity has more than doubled in adults. This epidemic is associated with many cardiovascular and metabolic disorders. Training strategies exist for weight reduction, one of which is heat stress. Evidence has shown that exercise combined with heat therapy provides cardiovascular health benefits. Research is lacking on the use of a heat stress on health parameters for overweight or obese individuals. The purpose of this study was to quantify the effect of health-related benefits associated with exercise training using a sauna suit in a cohort of overweight and obese individuals. Methods: Overweight or obese, sedentary, but low risk men and women (n=45) were randomized to the non-exercise control group or one of the two training groups. Exercise training was five days a week for eight-weeks. Monday, Wednesday, and Friday were 45 minutes long training sessions at a moderate intensity based on an individual's heart rate reserve (HRR). Tuesdays and Thursdays were 30 minute long spin classes at a vigorous intensity based on an individual's HRR and were instructed by the principle investigator. Results: 45 men and women completed the study. After eight-weeks, V̇ O2max increased significantly (p<0.05) in the sauna suit with exercise group (ESS) when compared to the exercise alone (E) and control groups. Repeated measures ANOVA also showed a significant (p<0.05) improvement in body mass, body fat, blood glucose, RMR, and fat oxidation in the ESS group when compared to the E and control groups. Conclusions: A sauna suit in conjunction with exercise: 1) elicited significantly greater improvements in V̇ O2max, and 2) significantly improved obesity associated health parameters, which include: body mass, body fat, blood glucose, RMR, and fat oxidation. The novel findings of the present study suggest that a portable heat stress may improve health parameters in overweight or obese.
... Overall, the impact of heat acclimation to improve cardiovascular stability during exercise under heat stress has been well studied [9][10]18,20,24,26 . However, to our knowledge, no studies have investigated the effects of exercise training with a sauna suit on heat acclimation and performance. ...
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Purpose: The purpose of this study was to quantify the performance-related benefits to training with a sauna suit. It was hypothesized that training with a sauna suit would elicit better improvements in maximal oxygen uptake (VO2max), ventilatory threshold, and 5km time trial performance (in temperate and simulated hot environments). Methods: Apparently healthy and endurance-trained men and women (n=14) were match paired according to sex, VO2max, and 5km personal best times and subsequently randomized to a control group and treatment group. Participants in both groups completed usual volume and intensity of training for 14 days with the treatment group performing all training sessions in a sauna suit. Participants performed a maximal exercise test and 2 x 5km time trials (in temperate and simulated hot environments) at baseline and post-training. Weight was obtained before and after time trial performances to quantify sweat rate. Additionally, body core temperature was monitored continuously throughout each time trial performance in both environmental conditions. Results: After 14 days of training with a sauna suit there were significant (p < 0.05) improvements in VO2max (+9.1%) and ventilatory threshold (4.6%). The 5km time trial performances in both hot (52 sec) and temperate conditions (38 sec) were significantly faster (p < 0.05) in the sauna suit treatment group after 2wks of training. Relative to the control group, sweat rate and thermoregulation improved (p < 0.05) during the 5km heat time trial after 14 days of training with a sauna suit. Conclusions: Findings from the present study support the utility of training with a sauna suit as a novel form of heat acclimation. Indeed, the present study demonstrated that 14 days of training with a sauna suit elicited improvements in VO2max, ventilatory threshold, and time trial performances. A greater sweat rate and lower core temperature likely mediated improved time trial performances following training with a sauna suit.
... However, recent research suggests that training with heat stress can result in improvements beyond competing in heat. Van de Velde et al (2016) found that training in a suana suit for 30 minutes a day, 5 days per week for 6 weeks improved participants' VO 2 max and metabolic threshold by 8.5% and 8.4% respectively. Additionally, time to exhaustion in a simulated hot environment time trial was increased 61.7%. ...
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The mountain bike (MTB) discipline known as enduro involves competitors racing off-road bicycles on several timed, and primarily downhill, stages over several days with untimed "liaisons" in which competitors must commute to the next timed section within a specified time. Unlike the cross country MTB discipline in which climbs are often completed above 90% of their maximal oxygen consumption (VO 2 max) with no respite before descents (Macdermid, 2012) the uphill sections in enduro racing are completed below 90% VO 2 max and competitors have short rest periods between completing these climbs and starting the timed downhill stages. These stages also differ significantly from downhill MTB racing in that enduro stages tend to be longer and have fewer man-made features. However, the timed stages in enduro, like downhill, are raced primarily out of saddle and involve significant contribution from both lower and upper body musculature (Burr, 2012). Enduro MTB races typically take place in mountainous regions during the summer, meaning that competitors must consider environmental factors such as altitude and heat when preparing for these races. The purpose of this article is to address and present strategies for dealing with environmental factors that affect performance during enduro MTB events.
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Background Heat acclimation and acclimatisation (HA) is typically used to enhance tolerance to the heat, thereby improving performance. HA might also confer a positive adaptation to maximal oxygen consumption ( $$V{\text{O}}_{2\max }$$ V O 2 max ), although this has been historically debated and requires clarification via meta-analysis. Objectives (1) To meta-analyse all studies (with and without control groups) that have investigated the effect of HA on $$V{\text{O}}_{2\max }$$ V O 2 max adaptation in thermoneutral or hot environments; (2) Conduct meta-regressions to establish the moderating effect of selected variables on $$V{\text{O}}_{2\max }$$ V O 2 max adaptation following HA. Methods A search was performed using various databases in May 2020. The studies were screened using search criteria for eligibility. Twenty-eight peer-reviewed articles were identified for inclusion across four separate meta-analyses: (1) Thermoneutral $$V{\text{O}}_{2\max }$$ V O 2 max within-participants (pre-to-post HA); (2) Hot $$V{\text{O}}_{2\max }$$ V O 2 max within-participants (pre-to-post HA); (3) Thermoneutral $$V{\text{O}}_{2\max }$$ V O 2 max measurement; HA vs . control groups; (4) Hot $$V{\text{O}}_{2\max }$$ V O 2 max measurement, HA vs . control groups. Meta-regressions were performed for each meta-analysis based on: isothermal vs . iso-intensity programmes, days of heat exposure, HA ambient temperature (°C), heat index, HA session duration (min), ambient thermal load (HA session x ambient temperature), mean mechanical intensity (W) and the post-HA testing period (days). Results The meta-analysis of pre–post differences in thermoneutral $$V{\text{O}}_{2\max }$$ V O 2 max demonstrated small-to-moderate improvements in $$V{\text{O}}_{2\max }$$ V O 2 max (Hedges’ g = 0.42, 95% CI 0.24–0.59, P < 0.001), whereas moderate improvements were found for the equivalent analysis of hot $$V{\text{O}}_{2\max }$$ V O 2 max changes (Hedges’ g = 0.63, 95% CI 0.26–1.00, P < 0.001), which were positively moderated by the number of days post-testing ( P = 0.033, β = 0.172). Meta-analysis of control vs . HA thermoneutral $$V{\text{O}}_{2\max }$$ V O 2 max demonstrated a small improvement in $$V{\text{O}}_{2\max }$$ V O 2 max in HA compared to control (Hedges’ g = 0.30, 95% CI 0.06–0.54, P = 0.014) and this effect was larger for the equivalent hot $$V{\text{O}}_{2\max }$$ V O 2 max analysis where a higher ( moderate-to-large ) improvement in $$V{\text{O}}_{2\max }$$ V O 2 max was found (Hedges’ g = 0.75, 95% CI 0.22–1.27, P = 0.005), with the number of HA days ( P = 0.018; β = 0.291) and the ambient temperature during HA ( P = 0.003; β = 0.650) positively moderating this effect. Conclusion HA can enhance $$V{\text{O}}_{2\max }$$ V O 2 max adaptation in thermoneutral or hot environments, with or without control group consideration, by at least a small and up to a moderate–large amount, with the larger improvements occurring in the heat. Ambient heat, number of induction days and post-testing days can explain some of the changes in hot $$V{\text{O}}_{2\max }$$ V O 2 max adaptation.
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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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We sought to establish whether cardiorespiratory fitness had important implications for long-term cardiovascular risk among individuals classified as low risk by the Framingham Risk Score (10-year coronary heart disease risk <10%). Prognostic factors of long-term cardiovascular risk are needed for low-risk subjects who make up the largest percentage of the US population. The study population was composed of men and women, 30 to 50 years of age, who had a baseline medical exam at the Cooper Clinic, Dallas, TX, between 1970 and 1983. Eligible individuals were defined as at low risk for coronary heart disease by Framingham Risk Score at the time of study entry and had no history of diabetes (n=11 190). Cardiorespiratory fitness was determined by maximum graded exercise treadmill tests. Over an average 27±2-year period, 15% of low-fit (quintile 1) compared to 6% of high-fit (quintile 5) individuals died (P<0.001). A 1-metabolic equivalent level increase in baseline fitness was associated with an 11% reduction in all-cause deaths and an 18% reduction in deaths due to cardiovascular disease (CVD) after adjustment for age, sex, body mass index, systolic blood pressure, total cholesterol, blood glucose levels, smoking, and early family history of coronary disease. There was an incremental decrease in CVD risk with increasing fitness quintile, such that the high fit had the lowest adjusted 30-year CVD mortality rate (hazard ratio 0.29, 95% CI: 0.16-0.51) compared to the low fit. Cardiorespiratory fitness is associated with a significant reduction in long-term CVD among individuals identified as low risk by Framingham Risk Score. These data suggest that preventive lifestyle interventions geared to optimize cardiorespiratory fitness, even among a "low-risk" subset, should be considered to improve CVD-free survival. (J Am Heart Assoc. 2012;1:e001354 doi: 10.1161/JAHA.112.001354.).
Article
Heat therapy, such as sauna and hot tub, has become an increasingly regular therapeutical practice around the world since several studies have shown benefits of heat therapy in metabolic and cardiovascular diseases. The use of heat therapy in people with type 2 diabetes mellitus revealed a striking reduction of 1% unit in the glycated hemoglobin, suggesting this therapy for the treatment of diabetes. Herein, we shall discuss the use of heat therapy and the mechanisms involved, and suggest a provisional guide for the use of heat therapy in obesity and diabetes. Human studies indicate that heat therapy reduces fasting glycemia, glycated hemoglobin, body weight, and adiposity. Animal studies have indicated that nitric oxide and the increase in heat shock protein 70 expression is involved in the improvements induced by heat therapy on insulin sensitivity, adiposity, inflammation, and vasomotricity. Heat therapy is a promising and inexpensive tool for the treatment of obesity and diabetes. We proposed that transient increments in nitric oxide and heat shock protein 70 levels may explain the benefits of heat therapy. We suggest that heat therapy (sauna: 80-100°C; hot tub: at 40°C) for 15 min, three times a week, for 3 months, is a safe method to test its efficiency.
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[Two of the authors respond:] We agree with Herbert Nehrlich that there are many situations in which physicians would benefit from the assistance of health and fitness professionals. It is essential that such advice be sought from professionals who have received formal training and attained national accreditation. In North America1 these would be professionals certified by the Canadian Society for Exercise Physiology or the American College of Sports Medicine. Together, physicians and health and fitness professionals will be able to provide information that is based on sound physiological principles and a clear knowledge of the absolute and relative contraindications to exercise for a variety of populations. Giuseppe Lippi and associates correctly point out that vigorous exercise may lead to supplemental health gains in sedentary community-dwelling individuals. There is growing evidence to suggest that certain groups may benefit greatly from high-intensity exercise training. We1 have advocated high-intensity exercise training for sedentary individuals2 and patients with cardiovascular disease3 and chronic heart failure.4 However, we are careful to acknowledge that adherence to this form of exercise may be poor and the risk of musculoskeletal injury higher. Therefore, we must weigh carefully the potential advantages and disadvantages of vigorous exercise for each individual client. As pointed out by Ediriweera Desapriya and colleagues, discussion of the barriers to exercise and innovative means to deliver inclusive and culturally appropriate physical activity interventions is of great importance. Furthermore, more effective lifestyle interventions are required to address the global crisis of physical inactivity. We have worked diligently to address the barriers to physical activity and have taken a transdisciplinary approach to the creation of novel exercise interventions. More work is required to “develop and deliver” inclusive interventions for all, but we believe that our work1,5 is a step in the right direction. As Rajesh Chauhan and associates point out, the determinants of health are multifactorial and physical activity is not the sole factor influencing health status. However, physical inactivity is an independent predictor of the risk for many chronic diseases and premature mortality. In fact, the risk for chronic disease and premature mortality in North America appears to be about 20% to 50% greater among those with a physically inactive lifestyle.5 Furthermore, physical activity appears to be protective in the presence of other known risk factors for chronic disease. Therefore, there is compelling evidence to support the independent health benefits of physical activity.
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Physical activity (PA) and cardiorespiratory fitness (CRF) both have inverse relationships to cardiovascular (CV) morbidity and mortality. Recent position papers and guidelines have identified the important role of both of these factors in CV health. The benefits of PA and CRF in the prevention of CV disease and risk factors are reviewed. In addition, assessment methodology and utilization in the research and clinical arenas are discussed. Finally, the benefits, methodology, and utilization are compared and contrasted to better understand the two (partly) distinct components and their impact on CV health.
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The measurement of the respiratory gas exchange ratio (R) during a standard exercise test is used to detect the onset of anaerobic metabolism during exercise, which results from failure of the cardiovascular system to supply the oxygen requirements of the tissues. The method described uses end-tidal gas concentrations to calculate R while the exercise test is taking place. Blood sampling is unnecessary, and the results can be determined during the test, thus avoiding exhaustive exercise. The method provides an objective measurement of one of the factors influencing exercise tolerance.
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To study the association between the cardiorespiratory fitness (CRF) distribution and cardiovascular disease (CVD) risk measured as continuous scores for individual and clustered CVD risk factors and to explore the potential effect modification of this association exerted by weight status among adolescents. Cross-sectional study based on 1,247 youths aged 12-19 years in the 1999-2002 National Health and Nutrition Examination Surveys. CRF was estimated by a treadmill test and categorized into age- and sex-specific quintiles. Five established CVD risk factors - an adiposity index (sum of triceps and subscapular skinfolds), the homeostatic model assessment of insulin resistance, systolic blood pressure, triglycerides, and total cholesterol/high-density lipoprotein cholesterol - were standardized for age and gender and a clustered score calculated as their average. Regression analyses adjusted for race/ethnicity and family socioeconomic status assessed differences in CVD risk across CRF quintiles for the overall sample and after stratification by weight status. The mean clustered risk score decreased with increasing CRF in both males and females (p for trend <.001 and .004, respectively). The most significant decline in the clustered CVD risk score across CRF quintiles was observed from the first to the second quintiles (53.6% and 37.5%, in males and females, respectively). The association remained significant in both overweight and normal weight males and in normal weight females (p < .05). Most of the excess clustered CVD risk is found among adolescents within the lowest quintile of the CRF distribution. Among adolescents, very low fitness states should be avoided or intervened upon for purposes of primordial CVD prevention.