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Internaonal Journal of Environmental Health Engineering | Vol. 2 • Issue 1 | January-February 2013
1
INTRODUCTION
In many industrial, workers need to wear personal protective
equipment to protect themselves from hazards.[1] Chemicals
are the most important contaminants of workplace and the
respiratory tract is the most important entrance way of these
contaminants to the body, hence in many cases we are inevitably
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DOI:
10.4103/2277-9183.113216
Address for correspondence:
Dr. Habibollah Dehghan,
Department of Occupaonal Health Engineering,
School of Health Isfahan University of Medical
Sciences, Hezar Jerib Avenue, Isfahan, Iran.
E‑mail: ha_dehghan@hlth.mui.ac.ir
ABSTRACT
Aims: This study was done to evaluate the effect of three kinds of respiratory
protective equipments (RPE) on the heart rate in light, moderate and heavy
workload.
Materials and Methods: This study was performed on eleven healthy university
students (male) under controlled thermal conditions in a climatic chamber. The
mean (SD) of age, height and body mass index (BMI) were 24.1 (2.34) years,
172 (4.2) cm and 22.4 (1.1) Kg/m2, respectively. Subjects were participated in
the four intermittent exercises experiments (without RPE, valve, half‑face and
full‑face) on a treadmill in light, moderate and heavy workload. Duration of light,
moderate and heavy activities was 30, 30 and 20 min, respectively. Heart rate
was recorded every 5 min.
Results: The mean of heart rate in 11 subjects for without RPE trial in light,
moderate and high workload was 93.5±13.1, 109.7±18.1 and 119.6±25.8 beats
per min (bpm), for valve RPE was 102.8±9.7, 116.7±16.0 and 132.1±23.2 bpm,
for half‑face RPE was 102.4±11.42, 117.3±15.8 and 132.0±23.1 bpm and for
full‑face RPE was 109.3±14.7, 125±17.4 and 140.1±23.1 bpm, respectively. In
three work load, signicant differences between the mean of heart rate by using
three kinds of RPE trials showed with without RPE trial were observed (P‑value
< 0.001). Also, mean of heart rate in three workload levels when using full‑face
RPE trial was signicantly higher than valve and half‑face RPE trials. In the
valve and half‑face RPE trials, signicant differences were not detected
Conclusions: The results demonstrated that heart rate were signicantly
increased with wearing of three kinds of RPE. Full‑face RPE have a higher
effect on increasing heart rate than half‑face RPE.
Keywords: Heart rate, Respiratory protective equipments, workload
Department of Occupaonal Health
Engineering, School of Health, Isfahan University
of Medical Sciences, Isfahan, Iran, 1Department
of Ergonomics, School of Public Health
and Center for Health Research, Hamadan
University of Medical Sciences, Hamadan, Iran,
2Department of Biostascs and Epidemiology,
School of Health, Isfahan University of Medical
Sciences,Isfahan, Iran
Effect of respiratory protection equipments wear on heart
rate in different workload
Behnam Khodarahmi, Habibollah Dehghan, Majid Motamedzadeh1, Mohammad Zeinodini,
Seyed Mohsen Hosseini2
Copyright: © 2013 Khodarahmi B. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which
permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
This article may be cited as:
Khodarahmi B, Dehghan H, Motamedzadeh M, Zeinodini M, Hosseini SM. Effect of respiratory protection equipments wear on heart rate in different
workload. Int J Env Health Eng 2013;2:26.
original article
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Khodarahmi, et al.: The effects of respiratory protection equipments on heart rate
Internaonal Journal of Environmental Health Engineering | Vol. 2 • Issue 1 | January-February 2013
2
equipments valve type (Filtration class FFP2, JFY1021 model,
manufacture by APASCIANI), half‑face mask (included two
cartridge, made of rubber, Duetta P3 model, manufacture
by APASCIANI), full‑face mask (TR2002/BN model, made
of rubber, with a large filter, manufacture by APASCIANI).
These respiratory protection equipments typically are used
in Iran workplaces [Figure 1].
Before the first experiment, the subjects were required to read
an information sheet, on which the purpose, method, and risks
of the study were described, and then sign a consent form.
Then the experimental schedule was communicated to each
subject and was informed has adequate rest the night before
of exercise and avoids coffee or alcohol drinks and fatty foods.
Every subject on arrival to climatic chamber wore a sport
clothe. Then heart rate monitor closed on the chest and wrist,
and subject has to rest in the climatic chamber for 15 min.
At the end of 15 min, resting heart rate was recorded. After
rest the subject was started three exercises on a treadmill.
The exercise consisted of walking on a treadmill at a speed
of 1.34 m/s with no grade at the light (30 min) workload
and with 5 and 10% grade at the moderate (30 min) and the
high (20 min) workload, respectively. Each exercise followed
by 15 min rest period. During these exercises heart rate were
recorded every 5 min. All these steps were performed in four
conditions including: without RPE, valve RPE wear, half‑face
RPE wear and full‑face RPE wear. All subjects carried out
the experiments on four different days with one day off
between the experiment days. The experimental protocol
was approved by the Institution’s Ethical Committee of
Investigations Involving Human Subjects.[13]
Analysis of the data was performed by using repeated
measurement ANOVAs and paired t‑test in software SPSS16.
RESULTS
Mean (SD) heart rate of subjects for without RPE wear trial
in light, moderate and heavy workloads were 93.5 (13.1),
109.7 (18.1), 119.6 (25.8) bpm respectively, for valve RPE trial
were 102.8 (9.7), 116.7 (16.0), 132.1 (23.2) bpm, for half‑face
RPE trial were 102.4 (11.42), 117.3 (15.8), 132.0 (23.1) bpm
and for full‑face RPE trial were 109.3 (14.7), 125 (17.4),
140.1 (23.1) bpm, respectively.
to use respiratory protection equipments.[2‑5] Different types of
the respiratory protective devices including air‑purifying and
air‑supplying respirators are using in the work environment.
Despite respirators can reduce contact with the pollutants,
breathing load created by these devices has followed different
side effects.[2,4,6,7] There are high cardio‑respiratory strains in
jobs that need to wear respiratory protective equipment.[8]
White et al., did an experiment on the protective clothing
and air‑supplying respirator that increasing of heart rate and
rectal temperature were the main reasons for stopping the
experiment.[9] In the study of Louhevaara et al., on respiratory
protection equipment, was found that the use of respiratory
protection equipment can causes cardio‑respiratory strain.[10] In
a study at construction, foundry, shipyard and metal industries
that regularly used such kinds of respiratory protective
equipment, it was found that increase in mean heart rate
when using the respiratory protective equipment is equivalent
to aerobic strain of 12‑57% VO2 max.
[11] Also, another study
that examined the effect of wearing of respiratory protective
equipment on heart rate, was determined that mean heart rate
of subjects from 75‑94 beats per min in the state without use of
respirator was increased to 77‑98 beats per min in the state of
use of respirator in the work environment.[12] Previous studies
mainly have been done on air‑supplying respirators and few
studies on air‑purifying respirators have been conducted. Also
in previous studies, the effect of different masks on heart rate
has not been compared with each other. This study intended
to assess and compare the effect of three kinds of respiratory
protective equipment (valve, half‑face and full‑face) on heart
rate at three levels of workloads (light, moderate andheavy)
in neutral conditions.
MATERIALS AND METHODS
This study was performed under laboratory controlled conditions
in climate chamber for two months fromJanuary to February
(2011). Sampling method was simple random. Eleven healthy
medical university students (male) from 18‑30 years participated
in the study, which was approved by the physician. Their physical
characteristics mean (Standard Deviation) were: age 24.1 (2.34)
years, height 172 (4.2)cm and body mass index22.4 (1.1).
Inclusion criteria included lack of cardiovascular, respiratory,
epilepsy, diabetes diseases and musculoskeletal disorders,
subjects should not take medicines that affect on heart rate,
and body mass index was in normal range (18.5‑25). Exclusion
criteria also include, on request of the subjects, if subjects
suffered from fatigue during the experiments and were not
able to continued, and if heart rate reach to maximum heart
rate (220‑age).
Mean heart rate was measured using a heart rate monitor (Polar
RS100, Electro, Finland).This heart rate monitor was used
in different researches [11‑13]. Wet Bulb Globe Temperature
index was measured using a Microtherm WBGT (Casella
cel, U.K). We used three kinds of respiratory protection
Figure 1: Respiratory protection equipments used in this
study; (a) Valve (b) Half‑face and (c) Full‑face
c
b
a
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Khodarahmi, et al.: The effects of respiratory protection equipments on heart rate
Internaonal Journal of Environmental Health Engineering | Vol. 2 • Issue 1 | January-February 2013
3
Repeated measure ANOVAs showed that mean heart rate
among four trial (without RPE, valve RPE, half‑face RPE
and full‑face RPE) in three levels workloads were a significant
difference (P<0.001). Value of F for light, moderate and heavy
workloads obtained 74.31, 75.58 and 92.23 respectively. Paired
t‑test showed significant differences among mean heart rate in
without RPE trial and three kinds of RPE trials (P<0.001). Pair
wise comparisons among valve, half‑face and full‑face RPE in
three levels workloads showed mean heart rate for full‑face RPE
wear is higher than for valve and half‑face RPE but no significant
differences were observed between valve and half‑face REP in
three levels workloads that the P value for light, moderate and
heavy workloads were 0.599, 0.427 and 0.959, respectively.
In Figures 2‑4 mean heart rate changes for four trials in three
workloads were compared.
DISCUSSION
The experimental results showed heart rates significantly are
affected by wearing three kinds of RPE. In other words, mean
heart rate in valve, half‑face and full‑face RPE wear trials are
higher than without RPE trial in all workloads. The additional
heart rate caused by wearing valve RPE in light, moderate and
high workloads was 7, 9 and 13 bpm, respectively. For half‑face
RPE was 9, 8 and 13 bpm and for full‑face RPE was 16, 16 and
21 bpm, respectively. Laird et al., studied the effect on heart
rate of half‑face mask air‑filtering respirator, in this study 12
New Zealand workers, while working were examined that the
results showed use of respiratory mask additions to mean heart
rate by 2‑4 bpm.[12] Another study found the physiological
load of working with N95 half‑face mask in two different
workload (40W and 85W) was associated with additional
heart rate ranged from 8.3 to 10.8 bpm.[14] Results of these
studies were similar to our findings. However, Scanlan were
measured physiological effects of S10 full‑face respirator on
four healthy men that found the mean heart rate when using
of mask was less than unmask condition but this difference
was not significant.[15] Mean heart rate in full‑face mask
wearing condition was higher than valve and half‑face masks in
all three workloads. James et al., were measured physiological
responses caused by wearing half‑face and full‑face masks in
both moderate and high workloads that found mean heart rate
of full‑face mask was more than half‑face mask.[16] Result of
this study was similar to our finding. One of the reasons that
heart rate is higher for full‑face RPE, is breathing resistance
in full‑face RPE is higher than valve and half‑face RPE. As
studies is express high breathing resistance made it difficult
for the subject to breathe and take in sufficient oxygen.
Shortage of oxygen stimulates the sympathetic nervous
system and increases heart rate.[17] Perhaps higher weight
of full‑face RPE than valve and half‑face RPE is effective in
increasing heart rate. Hooper et al., compared the mean heart
rate between use of two types light weight and conventional
self‑contained breathing apparatus and found mean heart rate
was significantly lower in lightweight breathing protection
device. Hooper study shows that weight of respiratory
protection device is effective on heart rate.[18] However, weight
factor is considered more about self‑contained breathing
apparatus. In our study, weight difference between half‑face
and full‑face RPE was not high. No significant difference was
observed between valve and half‑face mask. Similar study, that
these two kinds of RPE were compared, was not found. As
Figures 2‑4 demonstrate the pattern of changes in mean heart
rate in three levels workloads amongst four trials (without
RPE, valve RPE, half‑face RPE and full‑face RPE) are similar.
Figure 2: Heart rate changes due to wear respiratory
protective equipments in light work load
80
90
100
110
120
0 5 10 15 20 25 30 35
Mean Heart Rate (bpm)
Time (min)
Without mask
Valve mask
Half-face mask
Full-face mask
Figure 3: Heart rate changes due to wear respiratory
protective equipments in moderate work load
80
95
110
125
140
0 5 10 15 20 25 30 35
Mean Heart Rate (bpm)
Time (min)
Without mask
Valve mask
Half-face mask
Full-face mask
Figure 4: Heart rate changes due to wear respiratory
protective equipments in heavy work load
80
100
120
140
160
0 5 10 15 20 25
Mean Heart Rate (bpm)
Time (min)
Without mask
Valve mask
Half-face mask
Full-face mask
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Khodarahmi, et al.: The effects of respiratory protection equipments on heart rate
Internaonal Journal of Environmental Health Engineering | Vol. 2 • Issue 1 | January-February 2013
4
Also, when subjects do not wearing RPE have the lowest heart
rate and when wearing full‑face RPE have the highest heart
rate. This study was conducted on men in the laboratory, it
is suggested that similar studies in workplace on women and
with more subjects be done.
CONCLUSIONS
Two principal conclusions emerge from the study. First,
wearing respiratory protection devices in different work
load produced a significant increase in heart rate. Secondly,
full‑face RPE have a higher effect on increasing heart rate
than half‑face RPE.
ACKNOWLEDGMENT
The authors wish to acknowledge to Vice Chancellery of Research
of IUMS for the financial support, Research Project, 289140; the
authors express their gratitude to Dr. Pourabdian and students who
cooperated in this study.
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Source of Support: Isfahan University of Medical Sciences, Conict
of Interest: None declared.
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