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Copyright © 2017 American College of Sports Medicine
Endurance Exercise Training and Male Sexual Libido
Anthony C. Hackney1,2, Amy R. Lane1, Johna Register-Mihalik1 1
1Department of Exercise & Sport Science and 2Department of Nutrition, Gillings School of
Global Public Health, University of North Carolina, Chapel Hill, NC
Accepted for Publication: 9 February 2017
. . . Published ahead of Print
Endurance Exercise Training and Male Sexual Libido
Endurance Exercise Training and Male Sexual Libido
, Johna Register
, Johna Register
-
-
Mihalik
Mihalik
1
Department of Nutrition, Gillings School of
Department of Nutrition, Gillings School of
Global Public Health, University of North Carolina, Chapel Hill, NC
Global Public Health, University of North Carolina, Chapel Hill, NC
Accepted for Publication: 9 February 2017
Accepted for Publication: 9 February 2017
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
Endurance Exercise Training and Male Sexual Libido
Anthony C. Hackney1,2, Amy R. Lane1, Johna Register-Mihalik1, and 1
1Department of Exercise & Sport Science and 2Department of Nutrition, Gillings School of
Global Public Health, University of North Carolina, Chapel Hill, NC
Running title: Exercise and Libido
Address correspondence to:
A.C. Hackney, Ph.D., D.Sc., University of North Carolina, CB # 8700 Fetzer Hall UNC-CH,
Chapel Hill, NC 27599, USA
Email: ach@email.unc.edu Fax: 919-962-0489 Tel: 919-962-0334
There was no internal or external funding in support of this project. The authors acknowledge
there are not Conflicts of Interests relative to this work. Also, the results are presented clearly,
honestly, and without fabrication, falsification, or inappropriate data manipulation, and the
present study do not constitute endorsement by ACSM.
Medicine & Science in Sports & Exercise, Publish Ahead of Print
DOI: 10.1249/MSS.0000000000001235
Department of Nutrition
,
Gillings
Gillings
School of
School of
, Chapel Hill, NC
, Chapel Hill, NC
Ph.D., D.Sc.,
Ph.D., D.Sc.,
University of North Carolina,
University of North Carolina,
Chapel Hill, NC 27599, USA
Chapel Hill, NC 27599, USA
ach@email.unc.edu
ach@email.unc.edu
Fax: 919
Fax: 919
-
-
962
962
There was no internal or external funding in support of this project. The authors acknowledge
There was no internal or external funding in support of this project. The authors acknowledge
there are not Conflicts of Interests relative to this work. Also, the
there are not Conflicts of Interests relative to this work. Also, the
honestly, and without fabrication, falsification, or inappropriate data manipulation, and the
honestly, and without fabrication, falsification, or inappropriate data manipulation, and the
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
ABSTRACT
Purpose: To study the associations between aspects of endurance exercise training and the sexual
libido in healthy men using a cross-sectional online survey study design. Methods: A developed
online survey questionnaire was utilized. The questionnaire was based upon pre-existing
validated questionnaires and use to assess elements of physical characteristics, exercise training-
habits and libido of participants (n=1077). Three evidence-based categories were created for the
primary outcome of total libido score and low, normal, and high response categories set. The
high and normal categories were combined to form a high/normal score group and the low
category formed a low score group. Odds ratios (OR) were calculated to examine group
categorization. Results: Age, training intensity, and training duration of participants had
significant (p<0.02) univariate relationships, with libido scores and were thus included in the
multivariate model. In the multivariate model, training intensity (p<0.0001) and duration
(p<0.002) components were the most significantly associated with libido group designation
(high/normal vs. low). Participants with the lowest (OR: 6.9; 95% CI: 2.6-17.9) and mid-range
training intensities (OR: 2.8; 95% CI: 1.4-5.3) had greater odds of high/normal libido state than
those with the highest training intensity. Participants with the shorter (OR: 4.1; 95% CI: 1.6-
10.0) and mid-range training durations (OR: 2.5; 95% CI: 1.3-4.8) at their current intensity also
had greater odds of high/normal libido score than those with a greatest duration. Conclusion:
Exposure to higher levels of chronic intense and greater durations of endurance training on a
regular basis are significantly associated with a decreased libido scores in men. Clinicians who
treat male patients for sexual disorders and, or council couples on infertility issues should
based up
based up
on preon pre
to assess elements of physical characteristics, exercise training
to assess elements of physical characteristics, exercise training
based categories were created for the
based categories were created for the
w, normal, and high response categories set. The
w, normal, and high response categories set. The
high and normal categories were combined to form a high/normal score group and the low
high and normal categories were combined to form a high/normal score group and the low
Odds ratios (OR) were calculated
Odds ratios (OR) were calculated
Age, training intensity, and training duration of pa
Age, training intensity, and training duration of pa
significant (p<0.02) univariate relationships, with libido scores and were thus included in the
significant (p<0.02) univariate relationships, with libido scores and were thus included in the
multivariate model. In the multivariate model,
multivariate model. In the multivariate model,
training intensity (p<0.000
training intensity (p<0.000
were
were
the most
the most
significantly associated with libido group designation
significantly associated with libido group designation
(high/normal vs. low). Participants with the lowest (OR: 6.9; 95% CI: 2.6
(high/normal vs. low). Participants with the lowest (OR: 6.9; 95% CI: 2.6
training intensities (OR: 2.8; 95% CI: 1.4
training intensities (OR: 2.8; 95% CI: 1.4
those with the highest training intensity. Participant
those with the highest training intensity. Participant
10.0) and mid
10.0) and mid
-
-
range training durations (OR: 2.5; 95% CI: 1.3
range training durations (OR: 2.5; 95% CI: 1.3
had greater
had greater
odds of high/normal libido
odds of high/normal libido
Exposure to h
Exposure to h
igher levels of chronic intense and greater durations of endurance training on a
igher levels of chronic intense and greater durations of endurance training on a
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
consider the degree of endurance exercise training a man is performing as a potential
complicating factor.
Key Words: hypogonadism, testosterone, sex drive, stress, health
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
Introduction
The Centers for Disease Control and Prevention reports that 1.5 million women in the US
(6%) are infertile (National Survey of Family Growth) and, the American Society for
Reproductive Medicine affirms that infertility affects men and women equally (2,29). Moreover,
in approximately 40% of infertile couples, the male partner is either the sole cause or a key
contributing cause of infertility (2). One of the factors influencing fertility in males is a low
sexual desire; i.e., decreased libido (2). Clinically decreased libido can manifest as Male
Hypoactive Sexual Desire Disorder (MHSDD - Diagnostic and Statistical Manual of Mental
Disorders [DSM-V]); which affects approximately 16-18% of the adult male population (8).
It is well known women who are involved with high levels of intensive exercise training
have an elevated risk for developing menstrual dysfunctions and potential infertility, especially if
the menorrhea as a result of hypothalamic-pituitary-gonadal (HPG) axis
disruption (31). Evidence indicates that exercising men develop a similar corollary HPG axis
ypogonadal Male Condition (EHMC) (16). In the male
condition a quasi-hypogonadotropic hypogonadism exists as testosterone and luteinizing
hormone levels are both suppressed; and, abnormal sperm characteristics are sometimes
manifested (3,14). Current evidence links the development of EHMC to the combining effects of
the volume and intensity of endurance exercise training in these men (3,14,16).
Testosterone is associated with many androgenic-anabolic processes in the male, and
while not universally accepted, it is thought to play a key role in male sexual libido (6). Being
more physically active has been shown to be beneficial reproductively for men who are
sedentary (or have a very low physical activity levels) as it results in improved testosterone
levels and libido (11,32). Conversely, there are many reports in the popular literature and on the
in approximately 40% of infertile couples, the male partner is either the sole cause or a
in approximately 40% of infertile couples, the male partner is either the sole cause or a
One of the factors influencing fertility in males is
One of the factors influencing fertility in males is
a a
l
ow
Clinically decreased libido can manifest as
Clinically decreased libido can manifest as
Male
and Statistical Manual of
and Statistical Manual of
8% of the adult male
8% of the adult male
population (
population (
omen who are involved with high levels of intensive exercise training
omen who are involved with high levels of intensive exercise training
have an elevated risk for developing menstrual dysfunctions and potential infertility, especially if
have an elevated risk for developing menstrual dysfunctions and potential infertility, especially if
as a result of
as a result of
hypothalamic
hypothalamic
Evidence indicates
Evidence indicates
that that
exercising men exercising men
ypo
ypo
gonadal M
gonadal M
hypogonadotropic
hypogonadotropic
hypogonadi
hypogonadi
levels are
levels are
both
both
suppressed
suppressed
;
;
manifested
(
3,14
3,14
). ).
Current eviden
Current eviden
ce links the development of
volume and intensity
volume and intensity
of
of
endurance
endurance
Testosterone is associated with
Testosterone is associated with
ile not universally accepted, it is
ile not universally accepted, it is
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
internet suggesting that men who participate in large amounts of endurance exercise training
(e.g., marathon running) can have suppressed testosterone and libido (3,5). An examination of
available peer-reviewed research literature, however, reveals the issue of libido status in males
engaged in endurance exercise has not been systematically or empirically studied. To this end,
we studied the associations between aspects of endurance exercise training and the libido status
in healthy men using a cross-sectional online survey study design.
METHODS
Development of the Survey Instrument
An online survey questionnaire was developed to assess elements of physical
characteristics, exercise training-habits and sexual libido of male participants. The questions
concerning exercise training-habits were based on the International Physical Activity
Questionnaire (IPAQ) and the Baecke Questionnaire; and followed recommendations of the
American Heart Association (1,4,12). The libido related questions were based on items within
the Androgen Deficiency in the Aging Male Questionnaire (ADAM), Sexual Desire Inventory
(SDI-2) and the Aging Male Symptoms (AMS) Scale (18,19,23,27). The IPAQ, Baecke, ADAM,
SDI-2 questionnaires and the AMS Scale are commonly used in research-clinical settings and the
validity of each has been assessed and reported elsewhere (
10,18,19,20,24,27). The completed online survey was reviewed by an exercise physiologist and a
fertility specialist who were not involved with the study to insure legitimacy of selected question
items (i.e., content validity). The completed questionnaire and procedures for distribution were
reviewed and approved by the University of North Carolina Institutional Review Board.
Participant consent was obtained via their online access to the questionnaire; and, in which they
xercise training and the libido status
xercise training and the libido status
online survey questionnaire was developed to assess elements of physical
habits and sexual
libido
ts were
based on
Baecke
Questionnaire
; and followed recommendations of the
Association
(
1,4,1
2
The libido related questions were based on
Androgen Deficiency in the Aging Male
and the Aging Male Symptoms (AMS) Scale
questionnaire
s
the
AMS Scale
validity
of each has
been assessed and reported
,18,19,20,24,2
7
)
The completed online survey was reviewed by an
fertility specialist who were not involved with the study to insure legitimacy of selected question
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
also indicated they were healthy and free of endocrine-related medical disorders and prescription
medication usage.
Survey Sample - Administration
The completed survey questionnaire was formatted into the Qualtrics (Quatrics, 2014)
online survey platform and made accessible through a specific world-wide web link
(https://jfe.qualtrics.com/form/SV_eWESbBdaONSuUPb). Subsequent to establishment of the
web link, a series of email notifications were sent to sports clubs, national sports organizations,
university athletic departments, and sporting magazines publicizing the existence of the survey
and the web link site for access (~300 club/organizations were contacted). These emails
requested announcement of the survey and encouragement of participation by individuals
associated with the group/organization. The target population was adult males (>18 years old)
involved with sporting activities (e.g., walking, running, bicycling, swimming) on a recreational
and competitive basis in North America. However, clubs and organizations associated with
endurance based activities (e.g., running, triathlons, bicycling) were predominately targeted since
EHMC is more prevalent in men engaged in such activities (3,14,16). The survey administration
period was January 2014 to January 2015. Approximately every four months reminder emails
were sent to prior contacts to encourage them to continue to promote and distribute information
about the survey.
Dependent measures
The survey was constructed in three parts. The first section addressed elements of the
participant involvement (e.g., gender, medical status) and physical
(Quatrics, 2014)
w
orld
-
wide web link
. Subsequent
to establishment of
clubs, national sports organizations,
sporting magazines
publicizing
the existence of the survey
club/organizations
were contacted)
requested announcement of the survey and encouragement of participation
associated with the group/organization
.
The target
p
opulation was
(e.g., walking, running, bicycling, swimming)
and competitive basis in North America.
However,
(e.g., running, triathlons,
more prevalent in men
engaged in
period was January 2014 to January 2015.
were sent to prior contacts
to encourage
about the survey.
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
characteristics/demographic information. The second part focused on exercise habits and history
of regular frequency of exercise (days/week), intensity of training effort (number of light,
moderate, hard sessions per week), duration of exercise (hours/session; total hours/week),
primary and secondary types-forms of exercise engagement, endurance sports competition
participation (type and number of events), years in training, stability of training (i.e., our intent
injury, tapering or overreaching), focus of
training (recreation, health, sporting competition), and physical activity requirements at work
(level of activity, minutes/day). Approximate oxygen uptake (VO2) percentages for respective
recommendations of Bouchard et al. (6). The third part of the survey addressed questions on
libido, targeting such issues as sexual activity, arousal, desire, attraction, fantasy, appetite,
fulfillment, needs for intimacy, and infertility issues or confounders (i.e., concussions, children
sired).
Parts one and two of the survey allowed participants to click on predetermined answer
button options, which provided appropriate ranges for each particular question and parameter
being assessed. Part three (libido) involved a three category format structure to the answer
options where participants clicked answer buttons of Yes, Maybe, No; and, based on answers
some follow-up questions were presented. Answers to part three were scaled and scored in a
Likert- ; answers were assigned plus or minus
values towards final libido score depending on the nature of the specific question. All libido
questions (15 in total) were scored and an aggregate total libido score computed (i.e., > score = >
libido).
stability of training
stability of training
(i.e., (i.e.,
our
our
tapering or overreaching)
tapering or overreaching)
,
focus
focus
activity
activity
requirements
requirements
at work
at work
Approximate oxygen uptake (VO
Approximate oxygen uptake (VO
22
) percent
) percent
ages
ages
for respective
for respective
The third part
The third part
of the survey
of the survey
addressed questions on
activity,
activity,
arousal, desire, attraction,
arousal, desire, attraction,
fulfillment, needs for intimacy, and infertility issues
fulfillment, needs for intimacy, and infertility issues
or confounders (i.e., concussions
or confounders (i.e., concussions
of the survey
of the survey
allowed participants to c
allowed participants to c
which provided appropriate ranges for each particular question and parameter
which provided appropriate ranges for each particular question and parameter
. Part three
. Part three
(libido)
(libido)
involved a involved a
where participant
where participant
s clicked answer
s clicked answer
some follow
some follow
--
up questions w
up questions w
Likert
-
values towards final l
values towards final l
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
Statistical analysis
All statistical analyses were conducted using IBM® SPSS ® v19 (2010). Frequencies
and missing data checks were conducted to confirm data integrity (i.e., relative to missing data).
Specific variables of interest included age categories, elements of exercise training intensity and
exercise training duration (see above) at the current levels of training; but all response variables
were included in initial analyses. Additionally, several exercise training variables were computed
in which elements of frequency, intensity and, duration relative to time (hour per week and years
of training) were integrated into composite scores to estimate overall dose of exercise effects.
Tertiles categories were created for the variables of interest listed above and three evidence-
based categories were created for the primary outcome of total libido score (30). The cut-points
representing the libido score categories were as follows: Low 7, normal 8-14, high 15. The
high and normal categories were combined to form a single high/normal score group and the low
category formed the low score group. Combining high/normal score groups was utilized since
the focus of the study was on the presence and occurrence of lower libido in relation to
endurance exercise training.
Demographic, exercise training, and libido characteristics of the participants were
summarized with the use of means, standard deviations, and percentages. Demographic and
exercise training outcomes potentially related to our primary outcome of libido score were
analyzed using univariate statistics (Chi-Square analyses and t-tests). Subsequently,
multivariable logistic regression (entry method) was utilized to determine adjusted odds ratios
(OR) and 95% confidence intervals (CI) for libido score (i.e., placement in high/normal vs. low
score group) for the factors with significant univariate relationships to libido score categories.
Alpha level for all analyses was set to 0.05 a priori.
; but all response variables
; but all response variables
everal exercise training variables were computed
everal exercise training variables were computed
time (
time (
hour per week and hour per week and
to estimate overall dose of exercise effects
to estimate overall dose of exercise effects
for the variables of interest
for the variables of interest
listed abovelisted above
and
and
primary outcome of t
primary outcome of t
otal libido score
otal libido score
categories were
as follows: Low
as follows: Low
7, normal 8
combined to form a single
combined to form a single
high/normal
score group
score group
..
C
C
ombining high/normal score groups
ombining high/normal score groups
the focus of the study was on the presence and occurrence of low
the focus of the study was on the presence and occurrence of low
endurance exercise training.
endurance exercise training.
Demographic,
Demographic,
exercise
exercise
training, and libido characteristics of the participants were
training, and libido characteristics of the participants were
summarized with the use of means, standard deviations, and percentages. Demographic and
summarized with the use of means, standard deviations, and percentages. Demographic and
exercise
exercise
training outcomes potentially related to our
training outcomes potentially related to our
analyzed using
analyzed using
univariate statistics (Chi
univariate statistics (Chi
multivariable
multivariable
logistic regression
logistic regression
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
RESULTS
A total of 1366 individuals responded to the survey. Only respondents meeting all study
criteria (n=1077; healthy male and 18 years or older, complete surveys ) were included in
the analyses. The mean (±SD) physical characteristics and demographic outcomes of the
participants are reported in Table 1.
Age, exercise training intensity, and training duration components of participants had
significant univariate relationships (p<0.02; Table 2) with libido scores and were thus included in
the multivariate model. In the multivariate model, training intensity (p<0.0001) and
duration (p<0.002) were significantly associated with libido score group designation
(high/normal vs. low). Total intensity was a computed variable representative of number of
training sessions at a low, moderate, hard intensity times the hours of each per week (~oxygen
uptake (VO2) percent for respective intensities were; and high
) (see Methods). Chronic duration was a computed value representative of hours per
week training times the number of years training (at current level).
Specifically, participants with the greatest amount of low intensity training (OR: 6.9;
95% CI: 2.6-17.9) and moderate amount training (OR: 2.8; 95% CI: 1.4-5.3) had greater odds of
being in the high/normal libido score group than those participants with a greater amounts of
high intensity training (Table 3).
Likewise, participants with lower duration amounts to their training (OR: 4.1; 95% CI:
1.6-10.0) and moderate duration amounts of training (OR: 2.5; 95% CI: 1.3-4.8) also had greater
odds of high/normal libido state than those with a greatest amounts of training duration (Table
3).
components
components
of participants of participants
had
scores
scores
and were and were
thus thus
included in
included in
the multivariate model. In the multivariate model, training
the multivariate model. In the multivariate model, training
intensity
intensity
(p<
(p<
0.000
(p<0.002) were significantly associated with libido
(p<0.002) were significantly associated with libido
score score
group designation
group designation
Total intensity was a computed variable representative o
Total intensity was a computed variable representative o
a low, moderate, hard intensity
a low, moderate, hard intensity
times
times
the
the
hours
of each
percent for respective intensities were;
percent for respective intensities were;
. Chronic duration was a computed value representative of hours per
. Chronic duration was a computed value representative of hours per
the number of year
the number of year
s training (
s training (
at
at
Specifically, p
articipants with the
articipants with the
greatest amount
17.9) and
17.9) and
moderate
moderate
amountamount
being in the
high/normal libido s
high/normal libido s
intensity
intensity
training training
(
(
Table 3)
Table 3)
Likewise, participants with
Likewise, participants with
10.0) and
10.0) and
moderate
moderate
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
Age was also a
OR: 1.9, 95% CI: 1.0-3.9) and those in the mid-age category (41-55 yr; OR: 1.9, 95% CI: 0.9-41)
were more likely to be in the high/normal libido score group than those participants in the oldest
age- 56 yr).
Cronbach alpha values within the current survey ranged from 0.64 to 0.88. These were
slightly lower than the values originally reported from the survey/questionnaires on which the
current one was based (see Methods).
DISCUSSION
In this cross-sectional survey study we found that an inverse relationship exists between
endurance exercise training factors and male libido scores. Specifically, higher amounts of
intensive training or training involving greater amounts of duration within the endurance
program were associated with lower libido scores. When comparing the OR responses among
libido score classifications, participants in the low score group were approximately 64.5 to
85.5% ([1-[1/OR]] x 100) more likely to fall in that category since they did greater amounts of
higher intensity exercise. Also the low libido score group were 60.0 to 75.6% more likely to fall
into that category since they were doing greater amounts of longer duration exercise training
(28). Conversely, the effect of low - moderate intensity and shorter - moderate duration exercise
training seemed highly comparable in clearly influencing the libido scores of the participants in a
positive fashion which is in support of prior published work (32).
To our knowledge this is the first scientific, research-based study to examine the issue of
male libido and endurance exercise training. Several surveys on sexual habits and exercise
training have been conducted previously by sporting magazines (e.g., Runners World) and
0.64 to 0.88. These
0.64 to 0.88. These
slightly lower than the values originally reported from the survey/questionnaires on which the
slightly lower than the values originally reported from the survey/questionnaires on which the
sectional survey study we found
sectional survey study we found
that an inverse that an inverse
relationship exist
relationship exist
and male libido scores
and male libido scores
.
Specifically,
intensive training or training involving greater amounts of duration within the endurance
intensive training or training involving greater amounts of duration within the endurance
lower
lower
libido libido
scores
scores
.
W
W
hen comparing the OR responses among
hen comparing the OR responses among
do score classifications, participants in the low
do score classifications, participants in the low
100)
more likely to fall in t
more likely to fall in t
higher intensity exercise
higher intensity exercise
. Also the low libido score group were
. Also the low libido score group were
into that category since they were
into that category since they were
Conversely
Conversely
, t
he effect of
he effect of
training seemed
training seemed
highly comparable in
highly comparable in
positive fashion
positive fashion
which is in support of prior
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
sporting goods manufacturers (e.g., Brooks Sports Inc., Seattle, WA, USA). However, the
constructs of the questions presented in those surveys were not based upon clinical assessment
instruments used in sexual behaviors and fertility research. Furthermore, the statistical
approaches employed with these surveys tended to be descriptive in nature and not analytical-
inferential.
Several recent laboratory studies have examined issues of sexual satisfaction and libido
with exercise, but the generalizability applicability (to the current study) of the findings are
hampered by the small sample sizes utilized (n < 20) and a focus on female participants (17,22).
The findings of these latter studies did suggest that an acute exercise session enhances sexual
arousal-desire via activation of the sympathetic nervous system (SNS), enhanced SNS activity is
a common response to a single bout of exercise (9). It is unclear if these aforementioned studies
used habitual exercisers (such as within the current study). This last point is an important
consideration as it is well established that exercise training improves the sensitivity of tissue
responses to the SNS via enhanced receptor actions, resulting in substantially lower overall
sympathetic autonomic neural tone following chronic training (9,15).
Our focus was to establish whether an association between libido and endurance training
characteristics exists. As noted an inverse relationship between the duration/intensity
characteristics of endurance training and libido was identified. However, why increasing
duration and, or intensity of exercise training reduces a male s libido score cannot be ascertained
from the data obtained in this study. This study was not designed to explore a potential
mechanism. As mentioned earlier, the presence of EHMC is more prevalent in endurance-trained
men and the condition is associated with lowered basal testosterone, which can be linked to
reduced libido. But, currently the only means of detecting the existence of EHMC is through
have examined issues of sexual satisfaction a
have examined issues of sexual satisfaction a
nd libido
nd libido
applicability (to the current study)
applicability (to the current study)
of the findings are
of the findings are
and a focus on female participants
and a focus on female participants
an acute
exercise
session
via activation of the sympathetic nervous system (SNS)
exercise
(
9
)
t is unclear if these
used habitual exercisers (such as within the current study)
it is well established that exercise training improves the sensitivity of tissue
via enhanced receptor actions,
neural
tone
following chronic training
Our focus was to establish whether an association between libi
Our focus was to establish whether an association between libi
characteristics
exists. A
exists. A
s noted a
s noted a
characteristics of endurance training and libido
characteristics of endurance training and libido
duration
and
and
, ,
or or
i
i
ntensity of
ntensity of
from the data obtained in this
from the data obtained in this
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
measurement of reproductive hormonal levels within the blood or saliva. The present study did
not ascertain hormonal profiles of the respondents. Hence, we cannot state whether EHMC was a
direct factor in our participants with lower libido scores. Likewise, select medication use (e.g.,
performance enhancing drugs [PED]), existing psychological disorders (i.e., depression), and/or
chronic low caloric intakes are well established factors associated with suppression of
testosterone and reduced libido (13,14,26). For participation, we asked our males if they were
healthy and not under medical supervision, thus we feel the likelihood of these factors
confounding our outcomes is unlikely -
adherence and must acknowledge these were potential confounders in our data.
Increased volumes of intensive exercise training may also result in greater levels of
physical and mental fatigue in an individual, which could
motivation towards sex. In the current survey, we did not ask participants to report on their
overall level of general fatigue or lethargy. Typically with excessive physical fatigue,
experienced exercising individuals reduce their training loads to allow recovery (25). Our
participants reported they were in a stable period of consistent training for a number of months at
the time of the survey. This last fact also suggests that they were not overreaching / overtraining
which is associated with the development of the Overtraining Syndrome, which is linked to
sexual dysfunction (15). Nonetheless, the influential aspects of general exercise fatigue from
chronic exercise training as a possible causative mediator of reduced libido scores seems a
logical likelihood and needs to be pursued in future research.
It was expected the age of the participants would be associated with libido score
categorization. We found the two younger age groups participants had a greater likelihood of
placement in the high/normal libido score group than the oldest age group. Evidence indicates
are well established factors associated with
are well established factors associated with
suppression of suppression of
For participation, we asked our males
For participation, we asked our males
if they
if they
were
were
healthy and not under medical supervision, thus we feel the likelihood of these facto
healthy and not under medical supervision, thus we feel the likelihood of these facto
potential confounder
potential confounder
s
in our data
in our data
.
.
ncreased volumes of intensive exercise training
ncreased volumes of intensive exercise training
may
also result
also result
physical and mental fatigue in an individual, which
physical and mental fatigue in an individual, which
could
could
In the current survey, w
In the current survey, w
e did not ask participants to report on their
e did not ask participants to report on their
level of general fatigue
or lethargy
or lethargy
.
T
T
y
y
pically with excessive
pically with excessive
y
y
y
exercising individuals reduce their training loads to allo
exercising individuals reduce their training loads to allo
participants reported they
were in a stable period of
were in a stable period of
the time of the survey
the time of the survey
.
This last fact also suggests
This last fact also suggests
which is associated with the
which is associated with the
development of the
development of the
sexual
sexual
dysfunction
dysfunction
(
(
15
15
)
)
.
.
Nonetheless, the influential aspects of
Nonetheless, the influential aspects of
chronic exercise training
chronic exercise training
logical likelihood and
logical likelihood and
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
that male libido does decrease with aging (13), and one could argue this was a factor influencing
membership in the low libido score group. However, Lindau and Gavrilova (21) report that
medically healthy men of this age group (i.e., 56 yr) have active sexual desires and not until
70-85 years of age may there be sizable declines; being ~50-80% less than that observed 20-40
years earlier in life. Relative to this last point, the odds ratio observed for the influence of
exercise training intensity and duration were of a significantly larger magnitude than that of age
alone.
We acknowledge our sample was one of convenience, with potential response bias and
hence is a limitation. We also asked our subjects to complete the questionnaire only once, but
with multiple reminded notices sent to organizations it is possible some duplication occurred.
Another aspect of our study which limits the interpretation and generalizability of the findings is
our reliance upon self-reports and recall from our respondents. As a result of these factors, our
findings should be viewed as preliminary in nature and more work on this topic is needed.
To conclude, this systematic study using an online survey approach suggests men
engaged in higher intensities and greater durations of endurance training on a chronic basis (i.e.,
years) are significantly associated with decreased libido scores. Although our findings are
preliminary, the results suggest that clinicians who treat male patients with regard to Male
Hypoactive Sexual Desire Disorder and/or council couples on infertility issues should take into
account the degree of endurance exercise training a man is performing as a potential
complicating factor.
for the influence of
for the influence of
larger magnitude than that of
larger magnitude than that of
age
ur sample was one of convenience, with potential response bias
ur sample was one of convenience, with potential response bias
We also asked our subjects to complete the questionnaire only once, but
We also asked our subjects to complete the questionnaire only once, but
to organizations it is possible some duplication occurred.
to organizations it is possible some duplication occurred.
the interpretation and gen
the interpretation and gen
eral
and recall from our respondents.
and recall from our respondents.
viewed as preliminary in nature
viewed as preliminary in nature
and more work on this topic is
and more work on this topic is
, this systematic study using an online survey approach
, this systematic study using an online survey approach
igher intensities and greater
igher intensities and greater
durations of
durations of
are significantly associate
are significantly associate
d withd with
preliminary,
the
the
results
results
suggest that clinic
suggest that clinic
poactive Sexual Desire Disorder
poactive Sexual Desire Disorder
account the degree of
account the degree of
complicating
complicating
factor.
factor.
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
Acknowledgements
There was no internal or external funding in support of this project. The authors acknowledge
there are not Conflicts of Interests relative to this work. Also, the results are presented clearly,
honestly, and without fabrication, falsification, or inappropriate data manipulation, and the
present study do not constitute endorsement by ACSM. The authors wish to acknowledge the
support of all the different sports clubs and organizations that aided in the distribution of our
questionnaire.
The authors wish to acknowledge the
The authors wish to acknowledge the
support of all the different sports clubs and organizations that aided in
the
the
distribution of our
distribution of our
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
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Table 1. The physical and exercise training characteristics of the participants. *Mean and SD for
categorical rating of measurement (Age: 1: < 18 years = not included in analysis; 2: 18-25; 3: 26-
40; 4: 41-
Measurement
Minimum Maximum Mean SD
Age Group
(category)
2.0 5.0 3.39* 0.96
Weight
(kg)
51.8 159.0 76.4 12.3
Height
(m)
1.42 2.29 1.79 0.08
BMI*
(kg/m2)
16.0 35.0 23.63 3.06
12.3
12.3
0.080.08
23.63
23.63
3.06
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
Table 2. Summary of key responses from survey on aspects of exercise training characteristics
and elements. Associations * = statistically significant association with libido groups (Low vs.
Normal/High). Abbreviations: Med = medium (tertile), yr = year, IS = intensity sessions/week (#
low, # moderate, # high), T = tertile, hr = hour, hr/wk = hours per week, VO2% = approximated
VO2%/ IS (# low [ 35%], # moderate [50%], # high [ 70%]) (7). = rounding of numbers to
0.1 decimal (i.e., affects overall percentage totals).
Characteristic
Libido Score Group
Total X
2
p
Low
% (count)
Normal/High
% (count)
% (count)
Age*
(year)
18
25
33.3 (20)
18.8 (191)
19.6 (211)
0.000
0.000
26
40
13.3 (8)
38.5 (392)
37.1 (400)
41
55
25.0 (15)
28.8 (293)
28.6 (308)
> 56
28.3 (17)
13.9 (141)
14.7 (158)
Frequency
exercise (per
week)*
1
3
1.7 (1)
9.3 (94)
8.9 (95)
0.000
0.000
4
6
21.7 (13)
58.3 (589)
56.2 (602)
7
10
30.0 (18)
25.8 (261)
26.1 (279)
> 10
46.7 (28)
6.6 (67)
8.9 (95)
Hours of
exercise
(per week)*
1
3
1.7 (1)
9.6 (98)
9.2 (99)
0.000
0.000
4
6
10.0 (6)
33.1 (336)
31.8 (342)
7
10
23.3 (14)
35.0 (356)
34.4 (370)
> 10
65.0 (39)
22.2 (226)
24.6 (265)
Primary exercise
mode
Walking
1.7 (1)
1.9 (19)
1.9 (20)
0.711
0.711
Running
88.3 (53)
79.9 (812)
80.4 (865)
Biking
5.0 (3)
9.4 (95)
9.1 (98)
Swimming
0.0 (0)
1.0 (11)
1.0 (11)
Weightlifting
3.3 (2)
5.5 (56)
5.4 (58)
Other
1.7 (1)
2.3 (23)
2.2 (24)
Other exercise
modes regularly
performed*
Walking
no
63.3 (38)
70.8 (720)
70.4 (758)
0.219
0.219
Walking
yes
36.7 (22)
29.2 (297)
29.6 (319)
Running
no
81.7 (49)
73.3 (745)
73.7 (794)
0.150
0.150
Running
yes
18.3 (11)
26.7 (272)
26.3 (283)
Biking
no
71.7 (43)
68.1 (693)
68.3 (736)
0.568
0.568
Biking
yes
28.3 (17)
31.9 (324)
31.7 (341)
Swimming
no
90.0 (54)
85.2 (866)
85.4 (920)
0.301
0.301
Swimming
yes
10.0 (6)
14.8 (151)
14.6 (157)
*Wt. Lift
no
80.0 (48)
57.6 (586)
58.9 (634)
0.001
0.001
*Wt. Lift
yes
20.0
(12)
42.4 (431)
41.1 (443)
rounding of numbers to
rounding of numbers to
Total
Total
X
X
22
XX
X
Normal/High
Normal/High
% (count)
% (count)
% (count)
% (count)
18.8 (191)
18.8 (191)
19.6 (211)
19.6 (211)
0.000
0.000
38.5 (392)
38.5 (392)
37.1 (400)37.1 (400)
28.8 (293)
28.8 (293)
28.6 (308)
28.6 (308)
28.3 (17)
28.3 (17)
13.9 (141)
13.9 (141)
14.7 (158)
14.7 (158)
1.7 (1)
1.7 (1)
9.3 (94)9.3 (94)
8.9 (95)
21.7 (13)
21.7 (13)
58.3 (589)
58.3 (589)
30.0 (18)30.0 (18)
25.8 (261)
25.8 (261)
46.7 (28)46.7 (28)
6.6 (67)
6.6 (67)
1.7 (1)1.7 (1)
9.6 (98)
9.6 (98)
10.0 (6)
10.0 (6)
33.1 (336)
33.1 (336)
23.3 (14)
23.3 (14)
65.0 (39)
65.0 (39)
Walking
Walking
1.7 (1)
1.7 (1)
Running
Running
88.3 (53)
88.3 (53)
Biking
Biking
Swimming
Swimming
WeightliftingWeightlifting
Other
Other
Other exercise
Other exercise
modes regularly
modes regularly
performed*
performed*
Walking
Walking
Walking
Walking
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
Other
no
81.7 (49)
72.4 (736)
72.9 (785)
0.115
0.115
Other
yes
18.3 (11)
27.6 (281)
27.1 (292)
Compete
regularly*
No
28.3 (17)
47.8 (485)
46.7 (502)
0.003
0.003
Yes
71.7 (43)
52.2 (529)
53.3 (572)
Reason for
exercise training
*Wt. Loss
no
63.3 (38)
39.0 (397)
40.4 (435)
0.000
0.000
*Wt. Loss
yes
36.7 (22)
61.0 (620)
59.6 (642)
Stress Relief
no
40.0 (24)
30.1 (306)
30.6 (330)
0.106
0.106
Stress Relief
yes
60.0 (36)
69.9 (711)
69.4 (747)
*Enjoyment
no
50.0 (30)
14.5 (147)
16.4 (177)
0.000
0.000
*Enjoyment
yes
50.0 (30)
85.5 (870)
83.6 (900)
*Strength/Fit
no
70.0 (42)
34.9 (355)
36.9 (397)
0.000
0.000
*Strength/Fit
yes
30.0 (18)
65.1 (662)
63.1 (680)
*Competition
no
20.0 (12)
35.8 (364)
34.9 (376)
0.013
0.013
*Competition
yes
80.0 (48)
64.2 (653)
65.1 (701)
Physical activity
at work (per day)
< 30 minutes
58.3 (35)
66.9 (679)
66.4 (714)
0.121
0.121
30
60 minutes
28.3 (17)
16.7 (170)
17.4 (187)
1
2
hours
10.0 (6)
10.0 (102)
10.0 (108)
> 3 hours
3.3 (2)
6.3 (64)
6.1 (66)
Completed a
marathon*
No
31.7 (19)
45.6 (463)
44.8 (482)
0.035
0.035
Yes
68.3 (41)
54.4 (553)
55.2 (594)
Number of
marathons
completed*
1
3
19.5 (8)
43.8 (242)
42.1
(250)
0.001
0.001
4
5
7.3 (3)
12.1 (67)
11.8 (70)
6+
73.2 (30)
44.1 (244)
46.1 (274)
Completed a
triathlon*
No
61.7 (37)
75.6 (769)
74.8 (806)
0.016
0.016
Yes
38.3 (23)
24.4 (248)
25.2 (271)
Number of
triathlons
completed
1
3
52.2 (12)
48.6 (120)
48.9 (132)
0.799
0.799
4
5
13.0 (3)
10.1 (25)
10.4 (28)
6+
34.8 (8)
41.3 (102)
40.7 (110)
Concussions
No
76.7 (46)
75.1 (763)
75.2 (809)
0.785
0.785
Yes
23.3 (14)
24.9 (253)
24.8 (267)
Number of
Concussions*
1
84.6 (11)
50.2
(127)
51.9 (138)
0.044
0.044
2
15.4 (2)
31.6 (80)
30.8 (82)
3+
0.0 (0)
18.2 (46)
17.3 (46)
Years exercise
training at
current level
(year)*
< 1
3.3 (2)
6.4 (65)
6.2 (67)
0.002
0.002
1
2
8.3 (5)
20.6 (210)
20.0 (215)
3
5
20.0 (12)
31.0
(315)
30.4 (327)
6
10
20.0 (12)
14.9 (152)
15.2 (164)
> 10
48.3 (29)
27.0 (275)
28.2 (304)
Chronic i
ntensity
(T; IS x yr)*
Low (0
-
1100)
13.8 (8)
34.9 (324)
33.7 (332)
0.000
0.000
Med (1140
2480)
19.0 (11)
33.2 (308)
32.4 (319)
High
(2500
10000)
67.2 (39)
31.9 (296)
34.0 (335)
Exercise at
current level (T;
Low (< 1
2)
11.7 (7)
27.0 (275)
26.2 (282)
0.001
0.001
Med (3
10)
40.0 (24)
45.9 (467)
45.6 (491)
0.106
0.0000.000
0.000
0.000
83.6 (900)
83.6 (900)
36.9 (397)
36.9 (397)
0.000
0.000
0.000
0.000
63.1 (680)
63.1 (680)
34.9 (376)34.9 (376)
0.013
0.013
65.1 (701)65.1 (701)
66.9 (679)
66.9 (679)
66.4 (714)
66.4 (714)
0.121
0.121
16.7 (170)
16.7 (170)
17.4 (187)
17.4 (187)
10.0 (102)
10.0 (102)
10.0 (108)10.0 (108)
6.3 (64)
6.3 (64)
6.1 (66)
6.1 (66)
31.7 (19)
31.7 (19)
45.6 (463)
45.6 (463)
44.8 (482)
44.8 (482)
68.3 (41)
68.3 (41)
54.4 (553)
54.4 (553)
55.2 (594)
19.5 (8)
19.5 (8)
43.8 (242)
43.8 (242)
7.3 (3)7.3 (3)
12.1 (67)
12.1 (67)
73.2 (30)
73.2 (30)
44.1 (244)
44.1 (244)
61.7 (37)
61.7 (37)
75.6 (769)
75.6 (769)
38.3 (23)
38.3 (23)
24.4 (248)
52.2 (12)52.2 (12)
5
13.0 (3)
13.0 (3)
6+
6+
34.8 (8)
34.8 (8)
No
No
Yes
Yes
Number of
Concussions*
Concussions*
11
2
2
3+
3+
Years exercise
Years exercise
training at
training at
current level
current level
< 1< 1
1
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
y
ea
r)*
High (> 10)
48.3 (29)
27.0 (275)
28.2 (304)
Training hours
per week (T; hr)*
Low (1
-
6)
11.7 (7)
42.7 (434)
41.0 (441)
0.000
0.000
Med (7
-
10)
23.3 (14)
35.0 (356)
34.4 (370)
High (> 10)
65.0 (39)
22.2 (226)
24.6 (265)
Total intensity
(T; IS x hr/wk x
VO2%)*
Low (0
305)
8.6 (5)
33.9 (315)
32.5 (320)
0.000
0.000
Med (310
405)
22.4 (13)
33.0 (306)
32.4 (319)
High (410
1000)
69.0 (40)
33.1 (307)
35.2 (347)
Chronic Duration
(T; hr/wk x yr)*
Low (1
16)
11.7 (7)
31.0 (315)
29.9 (322)
0.000
0.000
Med (20
40)
21.7 (13)
34.9 (355)
34.2 (368)
High (50
100)
66.7 (40)
34.1 (346)
35.9 (386)
0.000
0.000
35.9 (386)
35.9 (386)
Copyright © 2017 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.
Table 3. Multivariate (logistic regression) model with adjusted odds ratios for libido score
group. Only significant clinical and biological factors noted.
Investigative
Variable
C
omparison
Between Tertiles
Odds Ratio
(placement in
high/normal
Vs. low)
CI (95%)
Chronic
Duration
Low
Low vs. High
4.0
1.6
10.0
Med
ium
Med
ium
vs. High
2.5
1.3
4.8
High
Total
I
ntensity
Low
Low vs. High
6.9
2.6
17.9
Med
ium
Med
ium
vs. High
2.8
1.4
5.3
High
Age
(years)
Low vs. High
1.9
1.0
3.9
Med
ium
(41
55)
Med
ium
vs. High
1.9
0.9
4.1
1.6 1.6
1.3
1.3
4.8
4.8
6.96.9
2.6
2.6
17.9
17.9
2.8
2.8
1.4
1.4
Low vs. High
1.91.9
vs. High
vs. High
1.9
1.9
