article, Young investigator
RESISTANCE TRAINING IMPROVES SLEEP QUALITY IN OLDER ADULTS A PILOT
1Department of Physiology, 2Department of Health, Exercise,
and Sport Sciences, 3Department of Pathology, Texas Tech University Health
Sciences Center/Texas Tech University, Lubbock, TX, USA
16 June 2005
Journal of Sports Science and Medicine (2005) 4, 354 - 360
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individuals, as a group, tend to experience difficulty sleeping compared
to younger adults. Improving sleep in the elderly would have beneficial
public health consequences. This study utilized 8 sedentary, older
adults, 78.1 ± 3.1 years of age, who participated in a six-month long
resistance training (RT) program. The Pittsburgh Sleep Quality Index
(PSQI) was used to examine sleep quality, and a 1 repetition max test
(1-RM) was used to determine upper (bench press) and lower (leg press)
body strength. Total strength, defined as the sum of the bench press
and leg press 1-RM results, was also reported. The training resulted
in significant improvements (p < 0.05) in total (19%) and upper
body (52%) strength and in sleep quality (38%). Future studies should
examine the effects of strength gain/loss and time-of-day training
on sleep quality.
WORDS: Chronic disease, resistance training, older participants,
process of aging results in many physiological changes. Arthritis,
diabetes, cancer, stroke, hypertension, and heart disease are chronic
conditions that commonly afflict the elderly. Further, the incidence
of most of these conditions, for both men and women >
70 years of age, increased over an 11-year period from 1984 to 1995
(Federal Interagency Forum on Aging-Related Statistics, 2002).
Researchers have recently postulated that the incidence of at least
20 chronic disorders can be reduced by regular exercise given that
modern lifestyles do not lend themselves to optimal gene expression
(Booth et al., 2002).
Human beings are endowed with a genetic legacy that evolved to meet
the challenges of the hunter/gatherer lifestyle, which is characterized
by frequent exercise, famine, and feasts (Booth et al., 2002).
In present times the abundance of easily affordable food, coupled
with a diminished requirement to exercise, is a situation encountered
by many, if not most, Americans. The quality of life in later years
in the United States is the focus of ever increasing attention given
the shifting demographics toward a society that is becoming increasingly
comprised of older citizens (Federal Interagency Forum on Aging-Related
Problems with sleep tend to occur as one gets older (Montgomery
and Dennis, 2002)
and these phenomena have health ramifications (Schubert et al.,
A notable consequence of insomnia, for example, is compromised function
during desired waking times (Neubauer, 2003)
which is a potentially dangerous condition. For example, chronic
insomniacs have 2.5 times more fatigue-related automobile accidents
than do good sleepers (Mendelson and Jain, 1995).
Monetary concerns also arise as a consequence of poor sleeping;
the need to purchase sleeping aides can be cost prohibitive for
older adults, many of whom are living on limited income and already
shoulder a substantial financial burden for health care costs (Crystal
et al., 2000).
Older adults also experience loss of muscle mass and strength as
they age (Hunter et al., 2004).
Tasks that younger adults take for granted, such as walking and
climbing stairs, can be challenging for many senior citizens. A
sedentary lifestyle, also common among the elderly, predisposes
one to injury thus exacerbating preexisting limited mobility, level
of activity, and accelerates the rate of decline of muscular function.
Studies have shown that exercise, under certain conditions, may
have beneficial effects upon sleep (Driver and Taylor, 2000),
however, the use of exercise as a treatment method (for poor sleep
or any ailment), is rare in clinical practice. Indeed, one only
has to sample the clinical literature to see examples of physical
activity underrepresented or missing altogether as a therapeutic
measure for those who suffer from poor sleep (Woodward, 1999;
In regard to the elderly with sleep problems, even in the research
literature there is variability in the between-studies average subject
age that may limit the extent to which conclusions can be generalized.
Further, a previous study has also implicated a time-of-day training
effect upon sleep; above a certain exercise threshold, regular exercise
in the mornings may promote sleep at night, while the same exercise
performed regularly in the evening may retard it (Tworoger et al.,
To the best of our knowledge few studies have been performed that
examine the effect of resistance training on sleep in older participants
who are not suffering from clinical depression. The present study
was designed to determine the effects of a 6-month resistance training
(RT) program performed in the mornings on strength and sleep in
older participants. We hypothesized that resistance training in
these older participants would result in significant improvements
in strength and sleep quality.
Eight older residents (> age 60) from a local assisted
living center completed 6 months of resistance training designed
to improve upper and lower body strength. At the initial screening
visit, consent was obtained and a medical history was documented.
Inclusion criteria included (i) male or female 60 years of age and
older, (ii) willingness to participate in a resistance training
intervention for 24 weeks, (iii) ambulatory, and (iv) consent of
their primary family doctor. Exclusion criteria included (i) any
uncontrolled chronic illness, (ii) current exercise volume of more
than 1 hour per week, and (iii) currently smoking. Participant description
is as follows: 3M/5F; age 78.1 ± 3.1 yr, average body mass index
26.4 ± 1.8 kg·m-2 (means ± SE). Participant use of sleeping
medication was not pronounced. Of the 8 participants, 6 never used
any sleep aides. Of the two that did report the use of sleeping
medication at the study onset, their use declined as the study progessed
(data not shown). The Texas Tech University Health Sciences institutional
review board approved the research protocol.
Resistance Training Protocol
Participants performed 1-circuit resistance training (RT) of bench
press, leg press, leg extension, rowing, shoulder press and arm
curl at 10-12 reps per exercise. Two minutes of rest was allowed
between each exercise. Each training session lasted approximately
30 minutes. Training began at 50% of the one-repetition maximum
(1-RM) and was increased as tolerated. Training was performed Monday,
Wednesday, and Friday mornings for 24 weeks on site using a Precor®
S3.21 Strength Multi-Station (Woodinville, WA, USA). The shoulder
press and arm curl were performed using dumbbells. The training
sessions were monitored by a certified fitness trainer.
At baseline, after 3 months, and after 6 months of RT, each subject
performed a 1-RM test to determine upper (bench press) and lower
(leg press) body strength. Briefly, the 1-RM was the greatest weight
the subject could lift as determined by a stepwise increase in the
load. The participants performed the exercise initially using submaximal
weight. As the load and perceived difficulty moving the load progressively
increased, the target number of repetitions per load decreased.
The 1-RM was the weight of the last successful lift.
To determine sleep quality, each participant completed the Pittsburgh
Sleep Quality Index (Buysse et al, 1989) at baseline, after 3 months,
and after 6 months of RT. The Pittsburgh Sleep Quality Index assesses
7 areas in arriving at a global score: sleep quality, sleep latency,
sleep duration, habitual sleep efficiency, sleep disturbance, use
of sleeping medication, and daytime dysfunction. The 7 domains are
each scored from 0 to 3, with a total or global score ranging from
0-21. A better sleeper would have a lower global PSQI score. The
PSQI may have several longitudinal applications in clinical practice
and research (Buysse et al, 1989), thus making it a logical sleep
assessment tool for this study. Previous studies have used the PSQI
to assess subjective sleep quality in the elderly with (Singh et
Li et al, 2004)
and without (Buysse et al, 1991)
multi-week exercise interventions. For the purposes of this study,
the use of sleeping medication, a component of the PSQI, and the
global PSQI score, were examined.
Data were analyzed using SigmaStat for Windows Version 2.03. All
values are presented as the means ± SE. A one-way repeated measures
analysis of variance (ANOVA) was used to examine differences among
the three reported 1-RM measurements and also for the sleep data.
A Student-Newman-Keuls post hoc test was performed where indicated.
Statistical signficance was accepted at p < 0.05.
The average 6-month attendance rate for the protocol participants
was 85.4 ± 3.9%. Figure 1 shows
mean strength values for the participants. RT yielded a significant
increase in total body strength (top panel) at 3 (p = 0.034) and
6 months (p = 0.034) relative to baseline (22% and 19%, respectively).
Upper body strength (middle panel) increased at 3 and 6 months,
however this reached statistical significance (p = 0.011) only at
the 6 month measurement period. RT yielded a 31% and 52% increase
in upper body strength at 3 and 6 months, respectively, relative
to baseline. No statistically significant changes in lower body
strength (lower panel) were detected at 3 and 6 months, however
lower body strength was increased by 16% and 9%, respectively.
Sleep quality, as measured by the PSQI global score, improved from
the beginning of the training period to the three month time point
(p = 0.043) (Figure 2). The
average sleep score was 5.0 at the study onset, and by 3 months
the average score was 3.1, a 38% decrease. A decrease in the global
PSQI represents an improvement in sleep. The trend of an increasing
slope from 3 to 6 months (a partial reversal in the measured sleep
improvements noted at 3 months) coincides with the loss of strength
gains in lower and total body strength which also occurred from
3 to 6 months as shown in Figure
studies have shown that aerobic exercise training can exert positive
effects on sleep quality. A 1997 meta-analysis (Youngstedt et al.,
showed that acute exercise increased total sleep time. Likewise,
older individuals also benefit from exercise training with respect
to sleep quality. A training regimen consisting of low-impact aerobics
and brisk walking resulted in improvements in participants' global
PSQI scores as well as improvements in various domains which contribute
to the global score (King et al., 1997).
Comparatively few studies have examined the relationship between
resistance training and sleep as opposed to aerobic-based regimens,
and fewer still have examined the effect of resistance training
on sleep in older participants. Singh and colleagues demonstrated
that a supervised weight-training program performed three times
per week for ten weeks yielded improvements in measured subjective
sleep quality for a group of depressed, mostly poor sleepers whose
average age was 71.3 ± 1.2 years (Singh et al., 1997).
Our results are in agreement with Singh et al. and indicate that
a regular resistance training program can improve major skeletal
muscle strength and sleep in older participants whose average age
is near 80, and who are characterized as "good sleepers."
The percent changes in strength parameters in the present study
are comparable to those reported previously for older adults (Vincent
et al., 2002).
This study utilized a multi-station machine (Precor® S3.21 Strength
Multi-Station) and dumbbells purchased specifically for the protocol.
All equipment was placed in a pre-existing physical fitness facility
located at the assisted living center. The average 6-month attendance
rate for the protocol participants was 85.4 ± 3.9%. We feel that
this approach combines the best aspects of home-based training (no
travel required, participants feel at ease) while simultaneously
providing a social network and social support that enhances compliance
and enjoyment of strength training (Seguin and Nelson, 2003).
It is possible that the improvement in sleep was due, to some extent,
to the social engagement that occurred while training in the facility's
fitness room. However, the results of a study by Morgan (2003)
support the possibility that the improvement in sleep was due to
the RT alone.
Lower body strength did not improve significantly from the resistance
training. This protocol contained 4 exercises that worked upper
body muscles; bench press, rowing, shoulder press and arm curl.
Two exercises, leg press and leg extension, worked lower body muscles.
Since our participants were sedentary, and ambulation, which utilizes
the lower limbs, is the common movement in all non- handicapped
individuals, we sought to emphasize upper body training. We viewed
it as likely that upper body strength in these individuals had diminished
more from disuse and therefore warranted an emphasis in resistance
training. It is also possible, however, that this emphasis in training
led to the disparities in strength gains seen in the lower and upper
body regions. Future investigations would be advised to ensure a
balanced approach regarding body regions exercised.
It is possible that as gains in strength taper, a corresponding
reduction of gain in sleep parameters also occurs. Although our
subject pool was not of sufficient size to yield a significant correlation,
the graphical trends are clear; from 3 to 6 months the average total
strength declined while the average global PSQI increased (worsened)
relative to the midpoint. This data is consistent with Singh and
who reported that increase in strength was a significant predictor
of the improvement in the total PSQI among depressed elders.
A topic receiving much attention is the of time-of-day training
effect on sleep. Our participants trained only in the mornings.
It would be informative if future research with older participants
contrasted the effects of an identical training intervention regularly
performed in the morning against one done in the evening. Multiple
studies are needed to address this issue because it appears that
exercise duration, as well as possibly intensity and other factors
determine if a given protocol is best performed in the early or
latter part of the day with respect to sleep quality.
It is known that acute exercise can lead to a stimulation of growth
hormone (GH) secretion (Weltman et al., 2003).
It is tempting to speculate that the involvement of GH and growth
hormone-releasing hormone (GHRH) subsequent to exercise were causative
factors in the noted sleep improvement. This is consistent with
the traditional hypothesis that sleep serves body restoration (Driver
and Taylor, 2000)
and hence exercise will improve sleep. Indeed, it has been suggested
that hypothalamic GHRH leads to anabolic restoration via GH release
and such activity coincides with a GHRH-induced promotion of NREM
sleep (Obal and Krueger, 2001).
The resistance training performed in this study may therefore have
resulted in an increased pulsatile release of endogenous GH at rest
yielding an increased 24-hour secretion. Such an outcome would be
consistent with the results from a study of older males who were
regular runners and age- matched sedentary controls; the runners
had higher resting GH levels (Hurel et al., 1999).
However, another study showed that the 24-h GH secretion in older
adults does not increase after a year of RT (Hartman et al., 2000),
but the authors in a review article (Wideman et al., 2002)
acknowledge that more investigation needs to occur before conclusions
can be made about the usefulness of RT for elevating GH in the elderly.
There are limitations related to the present study. The participants
in this study had an average baseline global PSQI of 5.0. The authors
of the paper in which the PSQI was introduced describe a poor sleeper
as one who has a global PSQI score of > 5. Hence, the participants
for this study, at the onset, are considered to have been "good"
sleepers, albeit barely. It is tempting to conclude that a strength
training intervention for the very old that do not sleep well would
be more beneficial, given the results with same-age good sleepers.
Future studies with elderly, poor sleepers are needed to confirm
(or disprove) this hypothesis. Additionally, the small sample size
limited the power of statistical analysis in this study and no control
group was utilized. The number of willing participants at the assisted
living center was limited and could be attributed to the fact that
there was no remuneration. The constraints of the inclusion and
exclusion criteria (see Methods) further restricted the size of
the experimental group, and the aforementioned factors likewise
precluded the creation of a control group.
resistance training performed three times per week in the morning
leads to an improvement in strength and sleep in older participants
whose average age is circa 80 years. We suggest future studies are
needed to explore the effects of different training times and strength
gains/losses upon sleep, as well as to determine the efficacy of
such regimens upon individuals who are characterized as poor sleepers.
gratefully acknowledge Allen Stephens, D.O., for his medical assistance.
We greatly appreciate the participants from Carillon who willingly
gave of their time during the study period. This work was supported
by a grant from the Helen Jones Foundation and The Carillon Research
and Education Center. The results of this study were presented as
a free communication at the 51st annual meeting of the American College
of Sports Medicine (2004), Indianapolis, IN.
sleep and deterioration of skeletal muscle mass and function are
commonly found among the aged.
show that RT led to improvements in upper and total body strength
in older participants who trained three times per week in the
resistance training led to improvements in sleep as measured by
a self-report sleep questionnaire, the Pittsburgh Sleep Quality
small sample size used, lack of control group, and the fact that
the participants on average were characterized as "good"
sleepers at the study onset, necessitates that further investigation
suggest that further research is required to explore the effects
of RT performed at different times of the day as well as to determine
the relationship between sleep gains or losses upon changes in
Lee T. FERRIS
Employment: Department of Physiology, Texas Tech University
Health Sciences Center.
Degree: MS (PhD candidate).
Research interests: Exercise training, cognitive function,
Employment: Departments of Health, Exercise, and Sport Sciences
and Physiology, Texas Tech University/Texas Tech Univ. Health
Research interests: Cardiopulmonary limitations to exercise,
control of breathing during exercise.
Employment: Departments of Pathology and Diagnostic &
Primary Care, Texas Tech University Health Sciences Center.
Research interests: Exercise intervention and bone pathology,
lipids and bone pathology including osteoporosis, osteoarthritis,
and skeletal metastasis
Employment: Department of Health, Exercise, and Sport Sciences,
Texas Tech University.
Research interests: Aging, women's health, fitness, exercise
Employment: Department of Health, Exercise, and Sport Sciences,
Texas Tech University.
Research interests: Aging and women's health