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Do blood pressure and heart rate responses to perceived stress vary according to endogenous estrogen level in women.

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AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 132:151–157 (2007)
Do Blood Pressure and Heart Rate Responses to
Perceived Stress Vary According to Endogenous
Estrogen Level in Women?
Tessa M. Pollard,1* Karen L. Pearce,2 Emily K. Rousham,3 and Joseph E. Schwartz4
1
Medical Anthropology Research Group, Department of Anthropology, Durham University, Durham, UK
Department of Anthropology, University of Massachusetts, Boston, MA
3
Department of Human Sciences, Loughborough University, Leicestershire, UK
4
Department of Psychiatry and Behavioral Science, State University of New York at Stony Brook,
Stony Brook, NY
2
KEY WORDS
premenopausal women; postmenopausal women; menstrual cycle
ABSTRACT
The results of experimental studies suggest that estrogen may blunt blood pressure responses to
stress, but increase heart rate responses. We investigated
whether within-person associations of perceived stress
with blood pressure and heart rate during normal working
life in 26 premenopausal and 7 postmenopausal women
varied according to endogenous estrogen level. Each
woman measured her own blood pressure and heart rate
and completed a diary reporting perceived stress levels on
six occasions on each of 2 working days. Premenopausal
women were assessed once between days 4 and 6 of their
menstrual cycle (low estrogen) and again between days 11
and 13 (high estrogen), and urine samples were taken to
verify expected variation in estrogen level. Results showed
that perceived stress was significantly positively associated
with systolic blood pressure (SBP), diastolic blood pressure
(DBP), and heart rate in the group as a whole. This association did not differ according to menopausal status. There
was no difference in the association of perceived stress with
SBP or DBP in premenopausal women according to day of
assessment, but heart rate reactivity to perceived stress
was significantly higher on the high-estrogen day. Our findings thus provide evidence that heart rate responses to perceived stress during everyday working life vary according
to estrogen level in premenopausal women, but no evidence
that blood pressure responses to stress vary according to
endogenous estrogen level in women. Am J Phys Anthropol
132:151–157, 2007. V 2006 Wiley-Liss, Inc.
Premenopausal women tend to show lower blood pressure reactivity and greater heart rate (HR) reactivity to
stressors than do men, according to a meta-analysis of
laboratory-based studies (Stoney et al., 1987). In line
with these results, Girdler and Light (1994) suggested
that men tend to be ‘‘vascular reactors,’’ while women
tend to be ‘‘myocardial reactors,’’ and noted that the former is more harmful with respect to cardiovascular disease risk. It has been hypothesized that these gender differences are partially explained by the effects of estrogen
on cardiovascular responses to stress in women, effects
which contribute to protection against cardiovascular
disease in women (Matthews, 1989; Light et al., 1998).
Those most likely to benefit would be premenopausal
women, particularly in populations where ovarian function is high, that is, in women living in western societies
(Ellison et al., 1993).
To improve our understanding of the effects of estrogen,
researchers have investigated cardiovascular reactivity to
experimental stressors in women with different levels of
estrogen. As expected, postmenopausal women have been
found to show a greater systolic blood pressure (SBP) response to mental stressors than premenopausal women
(Saab et al., 1989; Owens et al., 1993). However, findings in
relation to differences in diastolic blood pressure (DBP)
and HR reactivity to stress according to menopausal status
are less clear cut; Owens et al. found greater DBP reactivity
but not HR reactivity in postmenopausal women; Farag
et al. (2003), who looked at HR but not blood pressure, similarly saw no difference in HR reactivity, but Saab et al.
found greater HR reactivity but not DBP reactivity in postmenopausal women. Results from studies of the effects of
HRT on cardiovascular reactivity in postmenopausal women
are also potentially relevant to this issue, but are mixed and
difficult to interpret (Burleson et al., 1998; Del Rio et al.,
1998; Matthews et al., 2001; West et al., 2001; Matthews
et al., 2005). The administration of exogenous estrogen to
postmenopausal women may have very different effects than
endogenous estrogen in premenopausal women (Mendelsohn
and Karas, 2001; Mendelsohn, 2002), progestins are normally used in addition to estrogen; doses and methods of
administration vary, and effects may vary according to duration of HRT administration (Matthews et al., 2001) and time
since menopause (Brownley et al., 2004). Thus, these studies
are probably not informative about the possible effects of endogenous estrogen on cardiovascular reactivity to stress.
It has also been posited that if estrogen affects cardiovascular responses to stress, then cardiovascular reactivity to stress should vary over the menstrual cycle. To
C 2006
V
WILEY-LISS, INC.
C
*Correspondence to: Dr. Tessa Pollard, Department of Anthropology, Durham University, 43 Old Elvet, Durham, DH1 3HN, UK.
E-mail: t.m.pollard@durham.ac.uk
Received 15 September 2005; accepted 19 April 2006
DOI 10.1002/ajpa.20468
Published online 29 August 2006 in Wiley InterScience
(www.interscience.wiley.com).
152
T.M. POLLARD ET AL.
Fig. 1. Average patterns of variation in estrogen and progesterone over a menstrual cycle.
test this suggestion, researchers have typically compared
follicular and luteal phase responses to stress. Such
studies can make use of powerful within-person designs.
Results from studies that have verified menstrual phase,
usually by assessing progesterone, have been mixed.
Two studies found no differences in blood pressure or
HR reactivity to mental stress across different phases of
the menstrual cycle (Collins et al., 1985; Stoney et al.,
1990). One found higher HR reactivity, but similar blood
pressure reactivity, to mental stressors in the luteal
phase (when estrogen levels were comparatively high)
than in the follicular phase (Manhem et al., 1992).
Another found that during the late luteal phase, compared with their early follicular phase, women showed
similar blood pressure and HR responses to experimental stressors, but that the hemodynamic responses
underlying blood pressure elevations were influenced by
cycle phase, such that in the luteal phase there were
greater increases in cardiac output and lesser increases
in total peripheral resistance (Girdler et al., 1993). This
study verified progesterone levels but not estrogen levels, which may not have differed between the two assessments (between days 4 and 9 and between days 24 and
28). Unfortunately, the focus has consistently been on
identifying different reactions across different stages of
the menstrual cycle, rather than on attempting to isolate
the effects of estrogen. Estrogen levels vary across
both the follicular and luteal phases, while progesterone
levels, which may oppose the effects of estrogen to some
extent (Light et al., 1998), are high during most of the
luteal phase (Fig. 1).
Our aim was to investigate within-person associations
of stress with blood pressure and HR in women living
their normal everyday lives, and whether any such associations varied according to endogenous estrogen level.
In line with laboratory results, it has been shown previously that women’s blood pressure and HR rises in
response to stressors experienced in everyday life, such
as paid employment (James et al., 1996; Brown and
James, 2000). However, we chose to conduct tests of the
effects of estrogen on the association of perceived stress
with blood pressure and HR rather than of stressors per se,
which may have different meanings for different people.
Significant associations between momentary changes in
affective state and changes in blood pressure and HR in
everyday life have been demonstrated in men and
women (Gellman et al., 1990; Schwartz et al., 1994;
Brown et al., 1998; Kamarck et al., 1998). The general
conclusion, which is in line with experimental studies,
has been that any kind of emotional arousal, including
perceived stress, results in an increase in blood pressure
and HR in both men and women. We are unaware of any
such studies that have investigated differences in reactivity in women with different levels of endogenous
estrogen.
We tested three hypotheses: first, that changes in perceived stress in everyday life are positively associated
with changes in blood pressure and heart-rate in everyday life in a group of women; second, that postmenopausal women show greater blood pressure reactivity
and less HR reactivity to perceived stress in everyday
life than premenopausal women; third, that reactivity
differs at verified low and high estrogen stages of the
menstrual cycle, with lower blood pressure and greater
HR reactivity when estrogen is high. We chose to test
the third hypothesis using two assessments during the
follicular phase of the cycle: one early in the follicular
phase (days 4–6), when estrogen levels are expected to
be low, and one later in the follicular phase (days 11–13),
when estrogen levels are expected to be approaching
their midcycle peak (Fig. 1). Progesterone levels are low
throughout the follicular phase.
MATERIALS AND METHODS
Sample
The 33 female participants were university employees
in nonmanual jobs (mostly secretaries, administrators,
and academics), who responded to requests for volunteers
for a study on stress in women. Participants were told
that the aim of the study was to investigate the effects of
estrogen on the body’s responses to stress, but were not
informed about the precise hypotheses to be tested. Only
women who were not pregnant or breastfeeding, not taking oral contraceptives, hormone replacement therapy,
any other medication that would affect ovarian function,
or any medication likely to affect blood pressure levels
(e.g. antihypertensives) were included in the study.
Women were classified as postmenopausal if they had had
no menstrual period in the previous 12 months. Premenopausal women were asked to report the dates of their previous two menstruations and were only included if these
were within 24–35 days of each other and if they also
reported an average menstrual cycle within these limits.
Relevant biological and demographic characteristics of
the participants are shown in Table 1.
Study design
Each woman participated in the study for 2 working
days. Premenopausal women collected data once between
days 4 and 6 of their menstrual cycle, when estrogen levels are expected to be low, and once between days 11 and
13, when estrogen levels are expected to be substantially
higher (Fig. 1). Seventeen women participated on their
expected low estrogen day first and thus collected data
on days approximately 7 days apart, and eight participated on their high estrogen day first, and thus collected
data on days approximately 21 days apart. Although the
novelty of participation on the first day might potentially
increase overall perceptions of stress and thus perhaps
blood pressure and HR on that day, it was not expected
American Journal of Physical Anthropology—DOI 10.1002/ajpa
153
CARDIOVASCULAR RESPONSES TO STRESS IN WOMEN
TABLE 1. Characteristics of the participants and comparisons between premenopausal and postmenopausal women
N
Age range
Age (years)
Height (m)
Weight (kg)
BMI
Length of self-reported average
menstrual cycle (days)
Married or living with a partner
Yes
No
Smoker
Yes
No
Highest qualifications
High school
University degree
All
women
Premenopausal
women
Postmenopausal
women
Significance
of difference1
33
30–63
43.1 6 9.8
1.63 6 0.07
65.5 6 10.1
24.7 6 2.9
26
30–50
39.0 6 5.9
1.63 6 0.07
65.6 6 10.9
24.7 6 3.2
28.1 6 2.5
7
51–63
58.4 6 4.4
1.62 6 0.08
65.1 6 7.7
24.8 6 2.0
<0.001
0.76
0.90
0.97
26
7
21
5
5
2
0.62
6
27
6
20
0
7
0.30
15
18
10
16
5
2
0.20
Values are mean 6 SD.
1
t-tests were used to compare average values for continuous variables and Fisher’s Exact test to test for differences in categorical
variables.
to affect the relationship between perceived stress and
either blood pressure or HR, the main focus of this
study. For the seven postmenopausal women, the intervals between measurements were 5–8 days (5 women),
20 days (1 woman), and 22 days (1 woman).
On each day, the women collected their void of urine
on rising from bed, for assessment of estrone glucuronide. At the same time, the women made their first blood
pressure and pulse measurement and completed their
first diary entry. The blood pressure and pulse measurements were repeated at about 10 AM, 12:30 PM, 3:30 PM,
8 PM, and on retiring at the end of the day, and the diary
was completed at the same times. Women were prompted
to make the measurements by preprogrammed watches
set to beep within 10 min of the stated time. Participants then recorded in writing exactly when they completed their assessment. This variability was designed to
prevent precise anticipation of the prompt to collect data.
Data were missing for 20 observations from a possible
total of 396.
Methods
Participants were asked to fully void their urine just
before going to bed on the night prior to data collection,
and to record the time of voiding. They then collected all
urine produced on waking in the morning (and any produced during the night) into a calibrated jug. They indicated the volume of urine by placing some colored adhesive tape on the outside of the jug and then poured 5 ml
into a tube. This tube of urine was stored frozen until
collected by the researcher the following day and then
stored at 208C. Subsequently, one of us (KLP) measured levels of estrone glucuronide using the ovarian
(OM5) monitor, which performs a homogeneous enzyme
immunoassay (Brown et al., 1988). Twenty-four-hour urinary levels of estrone glucuronide measured using this
monitor correlate well with total amounts of urinary
estrogens over the same period (Brown et al., 1988).
Participants were provided with a small, automated
oscillometric blood pressure meter with a digital display
(AND UA-701) and shown how to use it to measure their
own blood pressure and HR. They practiced with the
researcher present until they were secure in the technique. They were also given an instruction sheet for reference during data collection providing full information
on how they should take their blood pressure. They were
instructed to sit down for all measurements. They took
one measurement at each assessment as is normal in ecological studies of within-person variation in blood pressure (e.g. Marco et al., 2000).
The diary was used to collect information about the
participants’ experiences over the hour before the assessment. They were asked to rate their level of stress on a
7-point scale, anchored at 1 (not at all stressed) and 7
(very stressed). Information was collected on tea, coffee,
alcohol, and food consumption, smoking, and physical activity (the latter assessed by asking ‘‘Have you walked or
cycled or had any other physical exercise (e.g., gardening, housework, sports)?’’) in the hour before the blood
pressure measurement. Data on tea and coffee consumption were combined to provide an indication of caffeine
consumption and all variables were coded yes/no. All
these variables have previously been shown to be associated with ambulatory blood pressure and HR (Carels
et al., 1998; Kamarck et al., 1998).
Each woman was weighed at the initial interview and
body mass index (BMI, weight/height2) was calculated
using self-reported height. Participants also reported
their smoking status.
Statistics
The development of multilevel mixed-model analyses
since the early 1980s has made possible powerful withinperson analyses evaluating associations between changes
over time in independent variables (in this case perceived stress) and changes over time in dependent variables (in this case blood pressure and HR) (Schwartz and
Stone, 1998; Brondolo et al., 1999). Heuristically, it is
convenient to imagine a time series in which both perceived stress and blood pressure have been assessed
many times for a single individual. A scatter plot could
be created with perceived stress on the horizontal axis
American Journal of Physical Anthropology—DOI 10.1002/ajpa
154
T.M. POLLARD ET AL.
TABLE 2. Averages and standard deviations of daily means and frequencies of reported behaviour for each person for all variables
Premenopausal women (N ¼ 26)
Day 4–6 of
menstrual cycle
Systolic blood pressure (mmHg)
Diastolic blood pressure (mmHg)
Heart rate
Perceived stress
Number of occasions physical
activity reported
Number of occasions food consumed
Number of occasions smoked
(smokers only, N ¼ 6)
Number of occasions caffeine consumed
Number of occasions alcohol consumed
113.2
72.4
69.7
2.7
1.2
6
6
6
6
6
Postmenopausal women (N ¼ 7)
Postmenopausal women (N ¼ 7)
Day 1
Day 2
Day 11–13 of
menstrual cycle
13.0
9.7
8.1
1.1
0.9
113.1
72.5
71.2
2.9
0.9
6
6
6
6
6
14.0
11.0
7.8
1.0
1.0
123.5
72.3
68.3
2.0
1.6
6
6
6
6
6
16.5
11.2
9.5
1.0
1.7
121.7
74.2
67.3
1.9
1.6
6
6
6
6
6
12.7
6.5
7.4
1.3
1.4
2.0 6 1.2
2.5 6 2.2
1.8 6 1.2
2.7 6 2.3
2.0 6 1.5
–
1.6 6 0.5
–
2.4 6 1.8
0.7 6 0.7
1.7 6 1.3
0.6 6 0.7
2.4 6 2.3
0.6 6 0.5
2.7 6 2.1
0.1 6 0.4
TABLE 3. Results of models predicting blood pressure and heart rate for the sample as a whole
SBP
Intercept
Age
BMI
Smoker1
Physical activity1
Food1
Cigarette1
Caffeine1
Alcohol1
Perceived stress
DBP
HR
Estimate
t
P
Estimate
t
P
Estimate
t
P
118.13
0.37
0.94
3.67
0.53
3.84
0.33
0.40
2.83
1.39
42.17
1.56
1.34
0.59
0.39
2.05
0.11
0.33
1.45
3.65
0.0001
0.13
0.19
0.56
0.69
0.04
0.91
0.74
0.15
0.0003
75.68
0.03
0.80
6.68
0.57
1.87
1.47
0.77
1.87
0.88
38.23
0.20
1.70
1.57
0.54
1.26
0.61
0.80
1.21
2.93
0.0001
0.83
0.10
0.13
0.59
0.21
0.54
0.43
0.23
0.004
71.14
0.03
0.07
5.00
2.67
3.00
1.99
1.66
3.50
0.98
6.43
0.24
0.20
1.45
2.03
1.64
0.69
1.39
1.84
2.69
0.0001
0.81
0.84
0.16
0.04
0.10
0.49
0.16
0.07
0.008
Age, BMI, and smoking status are between-person variables. Physical activity, consumption of a meal, cigarettes, caffeine, and alcohol, and perceived stress are within-person variables, varying over time. Observations used ¼ 376.
1
0, no; 1, Yes.
and SBP on the vertical axis, ignoring the timing of the
assessments, and a regression line could be fitted to the
points. Identification of a positive association would lead
to the conclusion that higher levels of perceived stress
are associated with higher SBP for this person. With
separate time series for each of many individuals, the
pooled (similar to average) within-person association of
perceived stress and SBP is the association of interest,
but care must be taken not to confound this estimate
with any between-person association of average perceived stress with average SBP. In mixed models, this is
handled by correct specification of random effects or the
error structure of the residuals for the model.
Mixed models also allow simultaneous testing of betweenperson effects, and allow the examination of interactions
between between-person effects and within-person effects.
We used PROC Mixed, part of the SAS statistical package
(Littell et al., 1996), to perform a random-effects regression
analysis, providing estimates and tests of the significance of
between- and within-person effects. This analysis treats person as a random, rather than a fixed factor, which allows the
legitimate drawing of inferences to the larger population
from which any given sample is drawn (Schwartz et al.,
1994). The effect of our primary predictor, perceived stress,
was also treated as a random factor, since we hypothesized
that its effect would vary across individuals. To reduce the
complexity of the models, the effects of potential confounding
variables were treated as fixed. An advantage of this software is that it uses all of the available data; traditional repeated measures analysis of variance software typically
excludes all of the data from any participant who failed to
complete an assessment.
RESULTS
For descriptive purposes, averages of each individual’s
daily average SBP, DBP, and HR levels and perceived
stress scores are given in Table 2, together with the average number of occasions on which individuals reported
each of the behaviors included in our models.
Associations of perceived stress with
cardiovascular outcomes
Initially, models to test for associations between perceived stress and SBP, DBP, and HR were constructed,
using data from all 33 women (Table 3). All variables at
the between-subject (age, BMI, and smoking status) and
within-subject (physical activity, meal, cigarette, caffeine,
and alcohol consumption) levels, which were predicted to
affect blood pressure or HR, were also included in the
models. These variables were retained in the model despite the fact that many were not significantly associated
with the cardiovascular outcomes because there is good
reason to believe that their inclusion reduced error variance in the models. The results showed that perceived
stress was significantly and positively associated with
SBP, DBP, and HR. In fact, it was the strongest predictor
in each equation. Thus, when women reported more
stress, their blood pressure and HR were significantly
higher than when they reported less stress.
Premenopausal versus postmenopausal women
To test the hypothesis that pre and postmenopausal
women would show different associations of perceived
American Journal of Physical Anthropology—DOI 10.1002/ajpa
155
CARDIOVASCULAR RESPONSES TO STRESS IN WOMEN
stress with the cardiovascular outcome variables, menopausal status was added to the model, and the interaction effect between menopausal status and perceived
stress was tested. The interaction was nonsignificant in
all cases (P > 0.30), indicating that there was no significant difference between premenopausal and postmenopausal women in the association between perceived
stress and the cardiovascular outcomes.
High estrogen versus low estrogen days
in premenopausal women
Only those premenopausal women whose estrogen was
higher on the day when estrogen was expected to be
higher (days 11–13 of the cycle) were included in these
analyses. Six women were excluded on this basis, two
because they did not provide urine samples on 1 day and
four who had estrogen levels lower on days 11–13 than
on days 4–6. It is possible that these women experienced
anovulatory cycles, or that their estrogen levels started
to rise after the days 11–13 sampling. Mean levels of estrone glucuronide for the 20 remaining women on each
day are shown in Table 4.
For the 20 women with validated high and low estrogen days, we investigated whether the association between stress and blood pressure or HR differed significantly between the 2 days. This was achieved by adding
day (low or high estrogen) to the original model and testing the interaction between day and perceived stress.
The interaction effect was nonsignificant for SBP and
DBP (P > 0.60), but significant for HR (t ¼ 2.01, P ¼
0.05). Respecification of the model was used to obtain
separate coefficients for the association between perceived stress and HR on each day (see Pollard and
Schwartz (2003) for details) and showed that there was
a significant positive association between perceived stress
and HR on the high-estrogen day (estimate ¼ 1.36, P ¼
0.02), and a nonsignificant, slightly negative association
on the low-estrogen day (estimate ¼ 0.31, P ¼ 0.63).
DISCUSSION
Changes in perceived stress were highly significantly
and positively associated with changes in both measures
of blood pressure and with changes in HR for women in
this sample. This finding is consistent with the results of
one previous study of a mixed sex sample that measured
perceived stress and used ambulatory blood pressure
monitoring (Schwartz et al., 1994), as well as with studies relating more general measures of negative affect
and arousal to ambulatory blood pressure in women
(Brown et al., 1998) and mixed sex samples (Gellman
et al., 1990; Kamarck et al., 1998; Brondolo et al., 1999).
It provides further evidence that perceived stress affects
blood pressure and HR in women, as well as men, in
naturally occurring, everyday situations.
There was no significant difference between pre and
postmenopausal women in the association between perceived stress and blood pressure or HR. Unfortunately,
the number of postmenopausal women recruited was
small. Further studies are required to test whether, in
ecological situations, pre- and postmenopausal women
show similar or different blood pressure and HR responses to perceived stress.
There was no difference in the strength of the association between perceived stress and blood pressure ac-
TABLE 4. Mean levels of estrone glucuronide on each day
Premenopausal women
Low-estrogen day (N ¼ 20)
High-estrogen day (N ¼ 20)
Postmenopausal women
Day 1 (N ¼ 7)
Day 2 (N ¼ 6)
Estrone
glucuronide
(lmol/h)
Significance
of difference
58.89 6 16.02
168.37 6 85.5
<0.0011
42.02 6 7.06
45.14 6 6.67
0.422
Values are mean 6 SD.
1
Paired t-test.
2
Paired t-test for N ¼ 6.
cording to whether the measurements were taken on a
day of the menstrual cycle with low or high estrogen
levels. This is the first study to try to isolate the effects
of estrogen levels on the blood pressure and HR response to perceived stress explicitly, avoiding assessment during the luteal phase of the cycle, when progesterone levels are raised. It is also the first to investigate
differences in responses to perceived stress in relation
to the menstrual cycle, rather than responses to a
standardized stressor. Nevertheless, the null findings
replicate most previous studies that have tested for different blood pressure responses to stress at different
phases of the menstrual cycle. HR was, as predicted,
more strongly associated with perceived stress on the
high-estrogen day than on the low-estrogen day. Manhem et al. (1992) have previously noted a difference in
HR responses across the menstrual cycle, with higher
HR reactivity during a high-estrogen stage of the luteal
phase.
Estrogen may increase HR reactivity by increasing
parasympathetic withdrawal in response to stress (Burleson et al., 1998) and may act to enhance the contractivity of the heart (Girdler and Light, 1994). It has recently
been shown that changes in levels of estrogen over the
menstrual cycle are associated with corresponding
changes in many mechanisms regulating the cardiovascular system, including sympathetic activity and hormones that regulate plasma volume (Hirshoren et al.,
2002). However, these changes did not cause systematic
changes in either blood pressure or HR over the cycle, or
in blood pressure or HR responses to standing over the
cycle (Hirshoren et al., 2002). Thus, it is possible that
while estrogen affects mechanisms regulating blood pressure responses to stress, these mechanisms largely counteract each other, as suggested by Girdler et al. (1993).
Further investigations of mechanisms that may underlie
our finding of greater HR reactivity to perceived stress
when estrogen levels (but not progesterone levels) are
high are required.
The study participants took their blood pressure before
recording their mood, and thus, it is possible that their
blood pressure reading influenced their reports of mood.
However, it is unlikely, given what we know from previous studies, that the association seen here between perceived stress and blood pressure is purely an artifact of
this methodology, and there is no reason to expect that
this method would have influenced the findings in relation to differences in reactivity according to estrogen
level. It is also worth noting that in several studies,
measures of perceived stress or mood have not been
shown to mediate the effects of experiences such as
American Journal of Physical Anthropology—DOI 10.1002/ajpa
156
T.M. POLLARD ET AL.
being at work on blood pressure (Brondolo et al., 1999;
Marco et al., 2000). Thus, our finding that the effects of
perceived stress on blood pressure did not differ according to endogenous estrogen level does not exclude the
possibility that estrogen might have modified the effect
of any particular stressor on blood pressure. Finally, we
acknowledge that our sample was not representative of
working women, so that the generalizability of our findings may be limited.
CONCLUSIONS
We found that change in perceived stress was positively associated with changes in blood pressure and HR
in women, but we found no differences in blood pressure
reactivity to perceived stress in everyday life according
to endogenous estrogen level. We did find some evidence
that when premenopausal women have higher estrogen
levels, they exhibit greater HR reactivity to perceived
stress. Overall, our findings provide little evidence that
estrogen affected women’s cardiovascular responses to
perceived stress in a manner that might protect against
cardiovascular disease. Further ecological studies of the
effects of short- and long-term variation in estrogen levels
on cardiovascular reactivity to perceived stress in everyday life are needed to help resolve current uncertainties.
ACKNOWLEDGMENTS
The authors would like to thank Norma Jewitt for her
help with data collection.
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