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: [email protected].

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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948 RESPIRATORY CARE � JUNE 2021 VOL 66 NO 6

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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