Current issues and trends in Respiratory therapy
The Immediate Physiological Effects of E-Cigarette Use and Exposure to Secondhand E-Cigarette Vapor
Molly L McClelland, Channing S Sesoko, Douglas A MacDonald, Louis M Davis, and Steven C McClelland
BACKGROUND: Vaping continues to grow as an alternative to smoking and as a recreational activity
for people of all ages, including minors. The billion-dollar industry offers users a plethora of flavors,
nicotine concentrations, e-juice combinations, and devices. While some studies suggest vaping is benefi-
cial for certain ailments and as a smoking cessation tool, many studies report concerning health out-
comes associated with vape use. Recent FDA regulations have banned certain vaping products
following an increase of vaping-related lung injuries reported in 2019. Health care providers need to
better understand the physiological effects of vaping-specific products and the impact of secondhand
vapor. The specific aims of the present study were to understand the immediate effects on heart rate,
breathing frequency, blood pressure, blood sugar, SpO2, pulmonary function, and oral temperature fol- lowing e-cigarette use and secondhand vapor exposure. METHODS: A total of 149 volunteers partici-
pated in this study; 76 subjects vaped mint-flavored e-cigarettes with 5% nicotine for 20 min while
seated next to 73 nonvaping subjects who agreed to be exposed to the vapor. Health variables including
heart rate, blood pressure, breathing frequency, blood glucose, FVC, SpO2, and oral temperature were obtained prior to vaping or exposure to vapor and again after 20 min. RESULTS: Subjects who
vaped had significantly higher heart rate, breathing frequency, and oral temperature, and signifi-
cantly lower blood oxygenation levels (ie, SpO2) after vaping for 20 min. Nonvaping subjects exposed to vapor had significantly higher oral temperature after 20 min of exposure. Blood sugar and FVC
were not significantly affected by vaping or exposure to vapor. CONCLUSIONS: Vaping with mint-
flavored e-cigarettes with 5% nicotine for 20 min resulted in significant immediate physiological
changes. Exposure to e-cigarette vapor significantly increased oral temperature within the same
amount of time. Key words: vaping; secondhand vapor; e-cigarettes; short-term health effects; e-juice. [Respir Care 2021;66(6):943–950. © 2021 Daedalus Enterprises]
Introduction
As the use of e-cigarettes and vaping continues to rise in
replacement of cigarettes it is imperative that health care pro-
fessionals understand the physiological implications of vape
use.1,2 A few studies suggest that vaping improves some med-
ical conditions, such as tonsillitis and mental health.3,4
However, many other vape studies suggest the potentially
negative health effects of vaping. For example, toxins such as
acrolein, acetaldehyde, and formalin, noted in the pulmonary
system of vapers, are thought to be associated with the high
temperatures used to vaporize the e-juice.5,6 Respiratory tract
irritation, bronchitis, and persistent coughing are identified
Mr Sesoko and Dr MacDonald are affiliated with the College of Liberal Arts
and Education, University of Detroit Mercy, Detroit, Michigan. Dr Davis
and Dr ML McClelland are affiliated with the College of Health Professions,
University of Detroit Mercy, Detroit, Michigan. Dr SC McClelland is affili-
ated with North Woodward Internal Medicine, Clawson, Michigan.
Supplementary material related to this paper is available at http://www.
rcjournal.com.
This work was funded in part by the NIH BUILD grant for minority
scholars and the Faculty Development Research Fund of Detroit Mercy.
The authors have disclosed no conflicts of interest.
Correspondence: Molly L McClelland PhD, University of Detroit Mercy,
College of Health Professions, 4001 W. McNichols Road, Detroit, MI
48221. E-mail: mcclelml@udmercy.edu.
DOI: 10.4187/respcare.08596
RESPIRATORY CARE � JUNE 2021 VOL 66 NO 6 943
pulmonary disorders associated with vape use.7-9 Many other
disorders, such as increased susceptibility to cardiovascular
problems,10,11 bacterial overgrowth,12,13 increased risk for
overdosing,14 multiple-organ disorders,15 nicotine addiction,16
changes in weight,17 bleeding disorders,18 infections,19 neuro-
logical disorders,20 and chronic inflammatory lung condi-
tions,21 have all been associated with vape use. Increased
heart rate and blood pressure are some of the immediate
physiological responses found after vape use.22-25
Alarming numbers of young people are experimenting
with vaping, many as early as middle school.26 Children
that young typically start vaping out of curiosity or to fit in
with their peers. Children and young adults are not typically
concerned with the long-term health effects of their behav-
iors. Additionally, young people often hide such behaviors
from the adults in their lives, including parents and health
care professionals. Even though a health care professional
may be astute enough to ask a patient about vape use, many
patients will not disclose use or will underreport use. It
behooves health care professionals and researchers to better
understand the immediate health effects of specific types of
vape use. The information could help health care professio-
nals make more timely and accurate diagnoses in their
patients, or at least prompt health care professionals to ask
additional questions if they suspect their patient may be
vaping. Patient education about the potential negative
health effects of vaping would likely be much more effec-
tive using short-term implications rather than long-term
effects, especially in the younger population. Additionally,
understanding the short-term implications of vaping can
inform health care professionals of potential health prob-
lems that are likely to arise with continued vaping.
While the negative health effects reported in the literature
are concerning, most of the studies did not specify the type
of vape or composition of vape fluid used. There are thou-
sands of combinations of vape types, e-juices, flavorings,
nicotine concentrations, and length of vape time used by peo-
ple who vape. The plethora of various vape combinations
proved problematic in late 2019 when a national outbreak of
vaping-related lung injuries occurred.27 Identifying an etiol-
ogy for the increase in vape-related lung injuries proved
challenging. Most data suggest that the lung injuries were
occurring when chemicals were added to the e-juice, such as
tetrahydrocannabinol (THC) and vitamin E.27 Increased
numbers of vape-associated lung injuries were also linked
with the use nonregulated e-juice, often purchased from
uncontrolled sources instead of from regulated vape shops.27
As a result, federal and state agencies placed stricter regula-
tions on the billion-dollar vape industry, limiting the sale and
distribution of vape products.28-31
The purpose of this study was to understand the immedi-
ate physiological effects of electronic cigarette (e-cigarette)
use with a mint flavor and 5% nicotine, as well as the im-
mediate physiological effects of secondhand e-cigarette
vapor. The specific aims of the study were to understand
the immediate effects on heart rate, breathing frequency,
blood pressure, blood sugar, SpO2, pulmonary function, and
oral temperature following e-cigarette use and secondhand
e-cigarette vapor exposure.
Methods
This study utilized a mixed factorial experimental design
involving a between-groups factor (76 self-identified vape
users vs 73 self-identified nonvapers who expressed a will-
ingness to be exposed to secondhand vapor; total pooled
sample size: N ¼ 149) and several repeated measures fac- tors (pre- and post-vaping physiological measurements).
Physiological measurements included heart rate, breathing
frequency, blood pressure, FVC, SpO2, blood sugar, and
oral temperature.
Subjects from both vape and nonvape groups were asked
to come to the vape lab at the University of Detroit Mercy;
the study took place in a 12 ft by 12 ft enclosed room.
Windows remained closed throughout each session. All
subjects were instructed to not eat or drink for 60 min prior
to beginning the study. Upon arrival at the lab, all subjects
first provided informed consent and then completed a
health assessment form to determine family history and
identify predictors of health (Table 1). Thereafter, physio-
logical measurements were taken of all subjects. Subjects
QUICK LOOK
Current knowledge
Vaping is a relatively new, and rapidly growing, billion-
dollar industry. People of all ages, including minors,
engage in vaping. Some studies suggest vaping can be
useful to quit smoking, but many other studies report
concerning health-related effects associated with vaping.
The long- and short-term health effects of specific vape
products need to be better understood.
What this paper contributes to our knowledge
Our results indicate that people who vaped mint-
flavored e-cigarette products with 5% nicotine for
20 min had significant increases in their heart
rate, breathing frequency, and oral temperatures.
Additionally, they also had decreases in their SpO2 after 20 min of vape use. Vaping with this specific
product and e-juice did not significantly affect
blood sugar or FVC in the short term. People
exposed second hand to the mint-flavored e-ciga-
rette vapor with 5% nicotine did not experience any
of the same short-term health effects except for
increased oral temperature.
PHYSIOLOGIC EFFECTS OF E-CIGARETTES
944 RESPIRATORY CARE � JUNE 2021 VOL 66 NO 6
from the vape and nonvape groups were mingled during the
experimental sessions. Subjects in the vape group were
then provided with a JUUL vaping device (Juul Labs, San
Francisco, California) with mint-flavored e-juice and 5%
nicotine and instructed to vape at a steady pace per their
normal usage pattern. After 20 min of vaping, physiological
measurements were again taken of all subjects.
All physiological measurements were collected by a regis-
tered nurse or trained research assistant. Heart rate was deter-
mined with an automatic finger monitor. Systolic blood
pressure (SBP) and diastolic blood pressure (DBP) were
obtained with an automatic blood pressure machine while
the subject was seated with both feet on the floor; mean arte-
rial pressure was calculated using the following formula:
SBP + 2(DBP)/3. Breathing frequency was determined by
counting respirations for 15 s and multiplying by 4 to deter-
mine the frequency (breaths/min). FVC was determined by
exhaling into a PC-based spirometry device (Easy on-PC
Spirometry System with Spirometry sensor and software,
ndd Medical Technologies, Andover, Massachusetts). Each
subject received their own spirette and performed a series of
3 tests to determine FVC. The best result was included in the
study. Spirometry was performed according to manufact-
urer directions. Some of the standards established by the
Table 1. Demographic and Health Variables
Total
(N ¼ 149) Nonvape Group
(n ¼ 73) Vape Group
(n ¼ 76)
Age, y* 22.1 6 7.3 (18–63) 23.8 6 9.8 (18–63) 20.4 6 2.8 (18–36)
Gender*
Male 69 (46.3) 19 (26.0) 50 (65.8)
Female 80 (53.7) 54 (74.0) 26 (34.2)
Other 0 (0) 0 (0) 0 (0)
Present health
Excellent 63 (42.3) 35 (47.9) 28 (36.8)
Good 82 (55.0) 35 (47.9) 47 (61.8)
Fair 3 (2.0) 2 (2.7) 1 (1.3)
Poor 1 (0.7) 1 (1.4) 0 (0)
Recreational drug use*
Yes 37 (24.8) 7 (9.6) 30 (39.5)
No 112 (75.2) 66 (90.4) 46 (60.5)
Mental health treatment
Yes 31 (20.8) 13 (17.8) 18 (23.7)
No 114 (76.5) 59 (80.8) 55 (72.4)
Unsure 4 (2.7) 1 (1.4) 3 (3.9)
Lung disease*
Yes 26 (17.4) 7 (9.6) 19 (25.0)
No 123 (82.6) 66 (90.4) 57 (75.0)
Unsure 0 (0) 0 (0) 0 (0)
Oral disease
Yes 6 (4.0) 2 (2.7) 4 (5.3)
No 141 (94.6) 71 (97.3) 70 (92.1)
Unsure 2 (1.3) 0 (0) 2 (2.6)
Cardiac disease
Yes 6 (4.0) 3 (4.1) 3 (3.9)
No 143 (96.0) 70 (95.9) 73 (96.1)
Unsure 0 (0) 0 (0) 0 (0)
Cigarette use*
Yes 8 (5.4) 1 (1.4) 7 (9.2)
No 133 (89.3) 69 (94.5) 64 (84.2)
Unsure or former 8 (5.4) 3 (4.1) 5 (6.6)
Alcohol use*
Yes 89 (59.7) 38 (52.1) 51 (67.1)
No 59 (39.6) 35 (47.9) 24 (31.6)
Unsure or former 1 (0.7) 0 (0) 1 (1.3)
Data are presented as n (%) except age, which is presented as mean 6 SD (range). Percentages represent the percent of the sample or group that falls in a given response category.
* The 2 experimental groups were found to significantly differ from each other in preliminary analyses.
PHYSIOLOGIC EFFECTS OF E-CIGARETTES
RESPIRATORY CARE � JUNE 2021 VOL 66 NO 6 945
American Thoracic Society and European Respiratory
Society on proper spirometry procedures were also imple-
mented, including proper hygiene and infection-control
practices, proper use and calibration of equipment accord-
ing to manufacture directions, optimal display of all
results, trained equipment users, inclusion of subject data
(blinded), demonstration of proper use for subjects by the
researchers, and request to avoid smoking or vape use for
at least 60 min prior to participation in the study.32 Blood
sugar was determined via finger prick with glucometer
analysis. SpO2 was determined with a noninvasive finger
clamp, and oral temperature was measured with an oral
digital thermometer.
The study was approved by the institutional review board
at the University of Detroit Mercy. Volunteers were obtained
through announcements made on social media outlets (eg,
SnapChat, Instagram, Facebook), a university participant
recruitment website, word of mouth, and by invitation from
the researchers. All subjects were $ 18 y old and were required to provide written informed consent prior to volun-
teering in the study. Data collection occurred from April
2019 to January 2020. Each session had approximately the
same number of volunteer vapers and nonvapers. Subjects
signed up for available research sessions based on their avail-
ability. They were not matched on baseline characteristics
except for all being over the age of 18. Subjects were pro-
vided with $10.00 in compensation for their involvement in
the study. Prior to analysis, all data were de-identified to pro-
tect subject confidentiality, and all data were analyzed and
are reported in aggregate form.
Statistical Analysis
A multi-step process was employed once data were col-
lected. These steps included (a) evaluation of data quality
and data cleaning (eg, identification of missing or out-of-
range data points and imputation if needed, assessment of
normality of distributions and homogeneity of variance);
(b) power analysis to determine if the sample size was suffi-
cient to ensure adequate statistical power; (c) preliminary
analyses to determine if experimental groups were equiva-
lent on main physiological variables as well as demo-
graphic and health variables; (d) correlation analysis to
ascertain whether demographic and health variables were
significantly associated (at P < .05) to physiological varia- bles (used to identify potential covariates); and (e) main sta-
tistical analyses using mixed factorial analysis of variance
(ANOVA), ancillary statistical analyses to assess the influ-
ence of covariates using mixed factorial analysis of covari-
ance (ANCOVA), and nonparametric analyses (eg, Mann-
Whitney and Wilcoxon tests) to ensure that any significant
results with the parametric statistics remained significant
with these different forms of analysis. For all statisti-
cal analyses, a P value # .05 was used for statistical
significance. Other than the power analysis, all analyses
were done using SPSS software (Version 26; IBM,
Armonk, New York). Detailed information about the out-
comes of each of these steps and the findings of all analyses
completed can be found in the supplementary material
(available at http://www.rcjournal.com).
Results
Table 1 presents descriptive statistics and frequencies for
all demographic and self-reported health variables for the
total pooled sample and for each experimental group sepa-
rately. Preliminary analyses revealed that the vape and non-
vape groups differed significantly in terms of age, gender,
recreational drug use, lung disease, cigarette smoking, and
alcohol use. Analyses of pre-vape physiological variables
revealed a statistically significant difference in FVC
(P < .001), with the vape group producing the higher mean score. In addition, both pre-vape and post-vape physiologi-
cal variables were found to statistically correlate with one
or more demographic and health variables. These results
indicate that the 2 experimental groups cannot be viewed as
wholly equivalent pre-vape, and that demographic and
health variables may influence experimental effects and, as
such, need to be treated as covariates.
Given that the study used a 2 (between groups) by 2
(pre-post) experimental design, mixed factorial (also
known as split plot) ANOVA analyses were computed for
each of the physiological variables (Table 2). To evaluate
the impact of demographic and health variables on the
main results, 2 sets of mixed factorial ANCOVA analyses
were also computed. In the first set, age and gender were
used as covariates. In the second set, all 10 demographic
and health variables were used as covariates (Table 2).
The ANOVA for heart rate produced nonsignificant
main effects but a significant interaction effect (P ¼ .01, partial eta2 [hp
2] ¼ 0.04 [small effect]). This interaction remained significant after controlling for age, gender, and
the 8 health variables in the ANCOVA analyses. Inspection
of means indicates that exposure to vapor resulted in a
reduction in mean heart rate for the nonvape group,
whereas vaping contributed to an increase in mean heart
rate for the vape group.
The between-groups main effect for blood pressure was
found to be significant (P ¼ .042, hp2 ¼ 0.03 [small effect]), as was the interaction (P ¼ .02, hp2 ¼ 0.04 [small effect]). Examination of means across the study conditions
indicates that the nonvape group showed a reduction in
mean values at post-vape while the mean values at pre- and
post-vape remained similar for the vape group. When con-
trolling for covariates, the between-groups effect became
nonsignificant while the interaction remained significant.
Controlling for all demographic and health variables, how-
ever, resulted in the interaction becoming nonsignificant,
PHYSIOLOGIC EFFECTS OF E-CIGARETTES
946 RESPIRATORY CARE � JUNE 2021 VOL 66 NO 6
T a b le
2 .
P re -P o st V a p in g C o n d it io n s a n d R e su lt s o f M ix e d F a c to ri a l A N O V A a n d A N C O V A E x a m in in g P h y si o lo g ic a l V a ri a b le s a s a F u n c ti o n o f V a p e G ro u p (B e tw e e n G ro u p s)
N o n v a p e G ro u p
V a p e G ro u p
S ig n if ic a n t R e su lt s
P re -V
a p e
P o st -V
a p e
P re -V
a p e
P o st -V
a p e
A N O V A
A N C O V A
(a g e a n d g e n d e r c o v a ri a te s)
A N C O V A
(a g e , g e n d e r, a n d 8 h e a lt h v a ri a b le s
c o v a ri a te s)
H e a rt ra te , b e a ts /m
in 8 8 .8 1 6
1 8 .2 4
8 6 .8 3 6
1 8 .0 1
8 4 .2 0 6
1 6 .2 8
8 8 .1 2 6
1 5 .2 7
In te ra c t: P ¼
.0 1 h p 2 ¼
0 .0 4
In te ra c t: P ¼
.0 1 h p 2 ¼
0 .0 4
In te ra c t: P ¼
.0 3 h p 2 ¼
0 .0 4
B lo o d p re ss u re , m m
H g
9 4 .0 3 6
1 0 .0 5
9 0 .8 3 6
1 0 .2 9
9 5 .1 4 6
1 0 .7 4
9 5 .8 4 6
1 0 .0 7
B tw
G p : P ¼
.0 4 2 h p 2 ¼
0 .0 3
In te ra c t: P ¼
.0 2 h p 2 ¼
0 .0 4
In te ra c t: P ¼
.0 2 h p 2 ¼
0 .0 4
P re -P o st : P ¼
.0 2 h p 2 ¼
0 .0 4
B re a th in g fr e q u e n c y ,
b re a th s/ m in
1 1 .1 8 6
1 .1 5
1 1 .1 5 6
1 .1 0
1 1 .2 9 6
1 .0 2
1 1 .7 9 6
1 .0 6
B tw
G p : P ¼
.0 0 6 h p 2 ¼
0 .0 5
P re -P o st : P ¼
.0 4 0 h p 2 ¼
0 .0 3
In te ra c t: P ¼
.0 2 h p 2 ¼
0 .0 4
B tw
G p : P ¼
.0 0 9 h p 2 ¼
0 .0 5
P re -P o st : P ¼
.0 4 0 h p 2 ¼
0 .0 3
In te ra c t: P ¼
.0 2 h p 2 ¼
0 .0 4
B tw
G rp : P ¼
.0 3 h p 2 ¼
0 .0 4
P re -P o st : P ¼
.0 3 h p 2 ¼
0 .0 4
In te ra c t: P ¼
.0 1 h p 2 ¼
0 .0 4
B lo o d su g a r, m m o l/ L
9 7 .5 3 6
1 9 .1 9
9 8 .6 3 6
1 8 .0 5
9 4 .4 5 6
1 2 .3 4
9 6 .0 1 6
1 4 .7 3
N A
N A
N A
F V C , L /m
in 3 .9 7 6
.8 8
3 .9 7 6
.8 9
4 .7 9 6
1 .0 7
4 .7 3 6
1 .1 0
B tw
G p : P <
.0 0 1 h p 2 ¼
0 .1 4
N A
N A
S p O
2 , %
9 7 .9 7 6
1 .7 2
9 7 .3 7 6
2 .9 4
9 8 .2 0 6
1 .0 6
9 7 .7 1 6
1 .6 6
P re -P o st : P ¼
.0 0 9 h p 2 ¼
0 .0 5
P re -P o st : P ¼
.0 0 9 h p 2 ¼
0 .0 5
P re -P o st : P ¼
.0 0 7 h p 2 ¼
0 .0 5
O ra l te m p e ra tu re , � C
3 6 .5 9 6
.4 2
3 6 .8 2 6
.2 7
3 6 .5 1 6
.4 2
3 6 .7 8 6
.4 2
P re -P o st : P <
.0 0 1 h p 2 ¼
0 .2 1
P re -P o st : P <
.0 0 1 h p 2 ¼
0 .2 1
P re -P o st : P <
.0 0 1 h p 2 ¼
0 .2 3
P re -P o st v a lu e s a re
p re se n te d a s m e a n 6
S D . F o r th e n o n v a p e g ro u p , n ¼
7 3 fo r a ll a n a ly se s e x c e p t b lo o d su g a r, w h e re
n ¼
7 2 d u e to
th e e x c lu si o n o f a c a se
w it h a n e x tr e m e v a lu e . F o r th e v a p e g ro u p , n ¼
7 6 . O n ly
st a ti st ic a ll y si g n if ic a n t re su lt s a re
re p o rt e d fo r e a c h
a n a ly si s.
B tw
G p ¼
b e tw e e n g ro u p s m a in
e ff e c t
P re -P o st ¼
p re -p o st (r e p e a te d m e a su re s) m a in
e ff e c t
In te ra c t ¼
in te ra c ti o n e ff e c t
h p 2 ¼
p a rt ia l e ta -s q u a re d (e ff e c t si z e e st im
a te )
N A ¼
n o t a p p li c a b le
PHYSIOLOGIC EFFECTS OF E-CIGARETTES
RESPIRATORY CARE � JUNE 2021 VOL 66 NO 6 947
though the repeated measures main effect emerged as sig-
nificant (P ¼ .02, hp2 ¼ 0.04 [small effect]). The ANOVA for breathing frequency revealed signifi-
cant results for both main effects and the interaction effect,
with all effects remaining significant after the control of
covariates in the ANCOVAs. For the between-groups main
effect (P ¼ .006, hp2 ¼ 0.05 [small effect]), the vape group was found to produce the higher mean value. For the
repeated measures main effect (P ¼ .040, hp2 ¼ 0.03 [small effect]), post-vape mean values were higher. For the
interaction effect, (P ¼ .02, hp2 ¼ 0.04 [small effect]), the vape group demonstrated a greater mean increase at post-
vape.
With regard to blood sugar, ANOVA and ANCOVA
results were nonsignificant. For FVC, the ANOVA pro-
duced a significant between-groups main effect (P < .001, hp
2 ¼ 0.14 [medium effect]), with the vape group generat- ing the higher mean score. This finding became nonsignifi-
cant when controlling for covariates.
The ANOVA for SpO2 produced a significant repeated
measures main effect (P ¼ .009, hp2 ¼ 0.05 [small effect]), with both groups showing a reduction in mean values Post-
vape. This result remained significant after controlling for
covariates in the ANCOVAs. It is worth noting that SpO2 was
observed to be severely non-normal in our evaluation of data
quality. In response, nonparametric analyses were also com-
pleted. Mann-Whitney tests were used to evaluate betw-
een group differences in pre- and post-vape values, and
Wilcoxon tests were used to evaluate pre-post differences for
the nonvape and vape groups separately. Both Mann-
Whitney tests emerged nonsignificant, whereas the Wilcoxon
test was significant for the vape group only (P ¼ .01). The ANOVA for oral temperature generated a significant
repeated measures main effect (P < .001, hp 2 ¼ 0.21 [me-
dium effect]), with both groups having produced higher
mean values at post-vape. This result remained significant
after controlling for covariates in the ANCOVAs.
Discussion
The findings are important because people who vape
often do so in the presence of those not vaping, and second-
hand vapor effects are also an important health topic. It
should be noted that the volunteer vapers in this study had
higher rates of smoking use, recreational drug use, mental
illness requiring treatment, alcohol use, and lung diseases
compared to the nonvape subjects. Only 36.8% of vaping
subjects considered themselves to be in excellent health
compared to 47.9% of nonvapers, suggesting that people
who vape may think they are engaging in one or more
behaviors leading to unhealthy outcomes. Those underlying
differences in health risk behaviors and findings between
the 2 groups may have influenced the results of this study.
An interesting finding was the immediate changes in
heart rate that occurred in the subjects. The vaping subjects
had a significant increase in heart rate, a known outcome of
using nicotine.33 Vape devices deliver higher concentra-
tions of nicotine compared to cigarettes,34 so the increased
heart rate effects of vape use may be even more significant
than that observed with cigarette use. The increase in heart
rate among vapers has clinical implications associated with
sustained tachycardia. This statistically significant finding
requires additional clinical research as the effect size esti-
mate (ie, hp 2 ¼ 0.04) suggests a small effect size and may
not have major clinical importance for the health care pro-
vider but further research in this area is warranted.
Nonvaping subjects did not experience an increase in
heart rate; in fact, their heart rates decreased after being
seated for 20 min during the duration of the study, suggest-
ing that exposure to vapor does not have the same effect on
heart rate as actually using the e-cigarette product. Some
studies suggest that elevated resting heart rates are the
major contributing factor to cardiovascular disease, more
so than blood pressure status.33 Health care professionals
may want to consider educating patients on this risk factor
and suggest non-nicotine vape products for their patients
who vape or are using vaping as a means to quit smoking.
Vaping effects on blood pressure also proved to be a sig-
nificant finding in this study, but again with likely small
clinical importance (h2 ¼ 0.04). Similar to heart rate, non- vapers experienced a significant decrease in blood pressure
after being exposed to mint-flavored e-cigarettes with 5%
nicotine, likely associated with being seated and resting for
20 min throughout the duration of the study. The vaping
subjects’ blood pressure did not decrease but remained
unchanged from pre-vape status, suggesting that vaping
prevents the expected reduction in blood pressure during
times of rest. These findings are consistent with other stud-
ies reporting variable correlation between nicotine use and
elevated blood pressure.33,35,36 Clinically, this finding
should be considered in patients with other hypertensive
risk factors such as increased age, obesity, and hypercholes-
terolemia. Because people who vape do not experience a
reduced blood pressure during periods of rest like their non-
vaping counterparts, they are at risk for complications of
hypertension (eg, heart attack and stroke). An otherwise
small clinical importance could become a more serious
health concern in some patients who vape or are exposed to
vapor.
Another significant finding from this study was the
increased breathing frequency identified in the vape group.
vape users had significantly higher breathing frequencies at
both the pre- and post-vape intervals. The etiology for this
finding is unclear and requires further research. One possible
explanation is that extended vape use contributes to sustained
increases in heart rate and decreases in SpO2 levels, triggering
a compensatory increase in breathing frequency.
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Vaping with mint-flavored e-cigarettes with 5% nicotine
did not have a statistically significant effect on blood sugar.
This finding should be further tested with different vape fla-
vors, as many flavors are marketed as fruity or sugary. The
results suggest that vaping or acute exposure to vapor is
likely not a significant problem for patients with diabetes or
hypoglycemia relating to serum glucose levels.
Similarly, vaping or exposure to secondhand vapor in
this study did not produce any robust significant differences
between groups regarding FVC. While FVC does not
appear to change in the short-term for vape users or those
exposed to vapor, additional research examining long-term
FVC in both groups may yield different results and is worth
exploring. Furthermore, an examination of FEV1 may have
produced more sensitive findings compared to testing the
occurrence of airway obstruction following vape use or
vapor exposure (ie, FVC).
One of the more concerning findings from this study was
the significantly decreased SpO2 levels noted in vapers at
the post-vape assessment. The results indicate that vaping
with mint-flavored e-cigarettes with 5% nicotine signifi-
cantly decreased the oxygen level in the blood. Although
the findings suggest a small effect size (h2 ¼ 0 .05), this could have significant clinical implications, especially for
patients with other pulmonary disorders contributing to hy-
poxemia such as asthma or COPD. In addition to the
increase in heart rate associated with vaping, this oxygen
reduction further increases the user’s risk of hypoxemia.
Elevated heart rate in conjunction with hypoxemia
increases myocardial work load. Patients presenting with
symptoms of dyspnea, reduced cardiac ejection fractions,
fatigue, light headedness, or dizziness should be further
assessed for e-cigarette use. Patients with known cardiopul-
monary disorders are at increased risk of worsening symp-
toms if they continue to vape with mint-flavored nicotine
products. The effect may be similar for those exposed to
vapor, but our statistical analysis returned as nonsignificant
for the nonvape group, which suggests that nonvapers do
not have the same health risks as their vaping counterparts.
Finally, it was noted that both the vaping and nonvaping
groups had higher oral temperatures at post-vape. This find-
ing may be a little more obvious for the vape group as e-
cigarette devices operate on a lithium-battery system heating
the e-juice to temperatures of 215�C to aerosolize the liquid.31
It should be noted that the inhaled vapor is significantly
cooler than 215�C, but the heating elements in vapes can become very hot. It was surprising to note that people
exposed to secondhand vapor also experienced higher oral
temperatures post-vape, which suggests that the inhaled vapor
has heat. The results are clinically important at the medium
effect size (h2 ¼ 0.21) and should be a consideration for health care providers caring for patients who vape or are
exposed to vapor. These findings have an impact on oral
health because sustained elevated oral temperatures can kill
normal oral flora.37 More research is needed on the health
impact of persistently high oral temperatures associated with
vaping and exposure to secondhand vapor. Additionally, fur-
ther research needs to be conducted to determine why expo-
sure to secondhand vapor contributes to increased oral
temperature. The cause of this finding was not readily
apparent.
Conclusions
The immediate physiological effects of vaping with
mint-flavored e-cigarettes with 5% nicotine and exposure
to the vapor have significant effects on several health varia-
bles. The notion that vaping or being exposed to vapor is
safer than cigarette smoking may not necessarily be accu-
rate. Our results indicate that vaping with mint-flavored e-
cigarettes with 5% nicotine increases heart rate, breathing
frequency, and oral temperature and decreases SpO2 after 20
min of vape use. These short-term effects can have signifi-
cant long-term health effects, especially if sustained. These
findings have important implications for health care profes-
sionals who should be assessing for vape use in their
patients and providing education on the negative health
effects of use both in the short and long term.
Current evidence on vaping mostly focuses on long-term
effects. This study examining the immediate impact of vap-
ing provides evidence that there are acute effects related to
blood pressure, heart rate, SpO2, and oral temperature fol-
lowing short periods of use or exposure. These immediate
physiologic effects create an opportunity for clinicians to
provide education to their patients who may help them
make informed decisions about their choice to use vape
products. It also provides a foundation for further research
into the immediate and long-term health effects of vaping.
Additionally, people exposed to secondhand vapor do not
experience the same level of health effects as people who
vape, except for increased oral temperature after 20 min of
exposure to vapor. This finding has implications for youth
and others who are near people who vape. Education should
be provided to minimize secondhand vapor exposure.
Finally, results from the health assessment survey of sub-
jects indicate that people who vape are also statistically sig-
nificantly more likely to engage in other risky behaviors
such as alcohol and drug use (Table 1). Health care profes-
sionals should be aware of these potential risky behaviors
when caring for patients who vape and consider appropriate
interventions to reduce health risk.
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