|
EVALUATING THE EFFECTS OF A LOW VOLUME STAIRCLIMBING PROGRAMME ON
MEASURES OF HEALTH-RELATED FITNESS IN SEDENTARY OFFICE WORKERS
|
1School of Sports Studies, University of Ulster, Jordanstown, County Antrim,
UK, 2Institute for Sport and Health, University College Dublin, Belfield,
Dublin, Ireland, 3Department of Clinical Biochemistry, Institute of Clinical
Science, Queen's University, Belfast, UK, 4Department of Sport, Culture
and Arts, Strathclyde University, Glasgow, UK.
| Received |
|
10 May 2007 |
| Accepted |
|
18
July 2007 |
| Published |
|
01
December 2007 |
©
Journal of Sports Science and Medicine (2007) 6, 448- 454
Search
Google Scholar for Citing Articles
| ABSTRACT |
| Despite its obvious advantages, few studies have examined health
outcomes of regular stariclimbing. In this study, we investigated
the training effects of eight weeks of stairclimbing on recognised
measures of health-related fitness in an occupational setting. Forty-five
public sector employees (22 male, 23 female) aged 42.3 ± 9.0 years
were randomly assigned to control (n = 16) or stairclimbing (n = 29)
groups. Stairclimbing training began with 1 bout 5d·wk-1 in week 1,
increasing by one climb per day every two weeks until week 5, where
a maintenance level of 3 climbs per day was reached. Participants
climbed on staircases located within an 8 storey office block, consisting
of 145 steps. The prescribed exercise intensity involved climbing
the 8 flights of stairs at a rate of 75 steps·min-1. All
participants agreed not to change their diet or lifestyle over the
experimental period. Relative to controls, the stairclimbing group
showed a significant increase of 9.4% in predicted VO2max
(p < 0. 05). No significant changes in blood pressure, blood lipid
concentrations or body composition were noted. These findings provide
evidence that stairclimbing can enhance an important component of
health-related fitness, namely cardiovascular fitness. Given that
such improvement resulted from less than 30 minutes per week of moderate
exercise, stairclimbing in the workplace should be promoted as a health-enhancing
physical activity.
KEY
WORDS: Exercise
therapy, physical fitness, dyslipidemias, occupational health.
|
| INTRODUCTION |
|
A physically active lifestyle is well established as a central
component in the maintenance of good health and disease prevention
(Shephard, 1999).
However, the majority of adults in our society appear reluctant
to undertake even the minimum exercise recommendation to achieve
discernible health benefits (Pate et al., 1995).
Moreover, the prevalence of sedentary behaviour is greater than
that for cigarette smoking, hypercholesterolemia, or hypertension
(U.S. Department of Health and Human Services, 1996).
Consequently, it has been postulated that the overall impact of
stimulating our society to engage in a more active lifestyle could
effectively lower coronary heart disease (CHD) rates, to a greater
extent than by altering any other single risk factor (Caspersen
and Heath, 1993).
The increased mechanization and automation of work procedures means
the longest sedentary phase in waking hours, for many people, occurs
during the working day (Ilmarinen et al., 1979).
The workplace has therefore been identified as a critical setting
for the delivery of interventions designed to reduce chronic disease
among adult populations (Oldenburg and Harris, 1996).
Ideally, the programme must not interfere with work, take only a
minimal amount of time, incur no financial costs, involve no special
equipment and be effective in altering health-related fitness (Booth
et al., 1997;
Bouchard and Shephard, 1994;
Ilmarinen et al., 1979;
Zunft et al., 1999).
One possible solution is the inclusion of stairwalking into the
daily schedule, particularly in an urban working environment that
offers few alternative forms of exercise (Winett and Carpinelli,
2000).
Stairclimbing is a familiar mode of activity that has been shown
to independently predict longevity in populations (Lee and Paffenbarger,
2000;
Paffenbarger et al., 1994).
Despite the apparent practicality of stairwalking in an urban occupational
setting, only a paucity of literature has investigated the potential
health benefits. The first report evaluating the feasibility and
efficacy of stairclimbing dates back to Fardy and Ilmarinen, 1975.
This investigation showed that, in a subgroup of men climbing about
25 floors·day-1 or 125 floors·week-1, maximal
oxygen consumption (VO2max) increased by about 10% over
a 12-week period. Four subsequent investigations with sedentary
men and women have been carried out; these studies have reported
improvements (≈5-25%) in VO2max (Fardy and Ilmarinen,
1975;
Ilmarinen et al., 1979;
Ilmarinen et al., 1978,
Boreham et al., 2005)
and other indices of cardiorespiratory fitness and blood lipid concentrations
(Boreham et al., 2000;
Boreham et al., 2005).
To date, the effects of smoking cessation and changes in dietary
habits on risk factors for CHD have been the focus of most worksite
health promotion interventions, with only a small number of randomised-controlled
trials targeting physical activity (Emmons et al., 1999).
Therefore, the purpose of the present study was to investigate the
effects of accumulated bouts of stairwalking on cardiorespiratory
fitness, body composition and blood lipids in sedentary office workers.
| METHOD |
|
Study design
This was an 8-week intervention study involving
previously
sedentary adults randomly assigned to stairclimbing or control
groups after baseline testing. In accordance with the Declaration
of Helsinki for Research Involving Human Beings (American
College of Sports Medicine, 1996),
the design and performance of each experimental procedure
was clearly formulated in an experimental protocol. The protocol
was approved by the Research Ethics Committee of the Queen's
University of Belfast, and each participant gave written consent
after a full explanation of the procedures and risks involved.
Measurements were made at baseline and again after 8-wk of
training.
Participants
Participants were recruited from employees at a public sector
office block. The procedures for selecting and screening for
the study are illustrated in Figure
1. In accordance with the ACSM recommendations on non-physician
supervised submaximal exercise testing, participants were
required to be stratified as moderate risk cases for coronary
heart disease (Franklin et al., 2000). Therefore, absolute exclusion criteria for volunteers
included known cardiovascular, pulmonary, or metabolic disease.
Relative exclusionary criteria included exceeding a threshold
of two or more risk factors for CHD and being considered by
a supervising physician to be unable to safely complete the
required exercise testing and prescription. Participants were
required to be non-smokers, not taking any pharmotherapeutic
drugs and sedentary i.e. not participating in a regular exercise
programme or meeting the minimal physical activity recommendations
(U.S. Department of Health and Human Services, 1996).
Assessment of morphological fitness
The measurements of height, body mass and subsequently body
mass index were determined using standard methods (Bray, 1978). Percentage body fat was assessed using bioelectrical
impedance analysis (Bodystat®1500; Douglas, Isle
of Man) using standard methods (Heyward and Stolarczyk, 1996).
Assessment
of cardiorespiratory fitness
Following 5 minutes of rest in a seated position, duplicate
measurements of resting blood pressure were made by the same
observer using standard methods (Black et al., 1997) with a validated automated sphygmomanometer (Omron HEM-705CP,
Washington, U.S.A).
After a habituation session within the testing environment,
VO2max was estimated using a sub-maximal multi-stage
exercise test on an electronically braked cycle ergometer
(SECA, Cardiotest 100, Hamburg, Germany). The YMCA test protocol
was used, consisting of two to four, 3-minute stages of continuous
exercise designed to raise the heart rate of participants
to between 110 beats·min-1 and 85% of age predicted
maximum in at least two consecutive stages (Golding et al.,
1989).
Heart rate was monitored by a short wave telemetry system
(Vantage NV; Polar Electro, Kempele, Finland). The work rate
corresponding to age-predicted maximum (220-age) was determined
by linear extrapolation of the sub-maximal heart rate responses,
using Microsoft Excel (Microsoft Excel
97, Microsoft Corporation, U.S.A). VO2max was the
then estimated from the work rate using the ACSM formula for
cycle ergometry (Franklin et al., 2000).
Assessment
of metabolic fitness
Venous blood samples (~10ml) were obtained from an antecubital
vein after a 12-hour overnight fast with participants lying
supine and rested for 5 minutes. Post-intervention samples
were obtained 60 hours after each participants' last stairclimb
to control for any possible transient effects of physical
activity on blood lipid concentrations (Crouse et al., 1997). At pre-intervention blood sampling, all female participants
were asked to complete a form indicating the stage of their
menstrual cycle. Post-intervention blood samples were scheduled
for the same stage of each individual's menstrual cycle, minimising
the potential effects of endogenous hormones on blood lipid
concentrations (Krummel et al., 1993). In the present study, all female participants reported
having normal menstrual cycles of between 27-32 days (Gordon
et al., 1998).
Within three months, pre- and post-samples were analysed for
total serum cholesterol, triglycerides and high density lipoprotein
cholesterol (HDL-C) using a Vitros® 950 IRC automated
analyser (Johnson and Johnson, U.S.A). The concentration of
low density lipoprotein cholesterol (LDL-C) was calculated
using the Friedewald formula (Friedewald et al., 1972). All samples were assayed in the same batch, within a
laboratory subject to external quality control (United Kingdom
National Quality Assurance Scheme). Within batch co-efficients
of variation on all tests were < 5%.
Exercise
prescription
Participants allocated to the exercise group embarked upon
an 8-week progressive stairclimbing programme. The programme
began with 1 bout of stairclimbing 5d·wk-1 in weeks
1 and 2, increasing by one climb per day every two weeks until
weeks 7 and 8, where a maintenance level of 3 climbs per day
was reached. Participants climbed in one of four identical
staircases located in the office block, consisting of 145
steps with a total vertical displacement of 23.9 metres. The
prescribed exercise intensity involved climbing the 8 flights
of stairs at a rate of 75 steps·min-1, which was
determined in a pre-programme familiarisation session as a
comfortable but brisk rate. Participants were instructed to
descend the stairs afterwards at their leisure.
To document the completion of each stairclimb all participants
kept training logs. Each bout of stairclimbing was integrated
into the working day at the convenience of the subject, with
a minimum of one hour between climbs. To encourage compliance
to the programme and the prescribed intensity of exercise,
all stairclimbers underwent once weekly supervised sessions,
supplemented by regular telephone calls. All participants
were also provided with contact numbers to telephone if they
needed help or information. All participants agreed not to
change their diet or lifestyle over the experimental period.
Statistical
analysis
Changes over time were adopted as a summary measure of the
response over time for each subject (Bland, 1995; Matthews et al., 1990). Mean changes were compared using an unpaired t-test
to identify differences in response between groups. The 0.05
level was used as criterion for statistical significance.
The results are presented as means and standard deviations.
|
| RESULTS |
|
Participants'
characteristics at baseline are presented in Tables 1
and 2. There were no
significant differences between groups for any variable, with
the exception of age and body fatness (p < 0.05). Compliance
within the stairclimbing group was good, with a mean 88.0
± 9.2 % climbs completed over the experimental period.
The changes in the dependent variables of interest
for the groups over the 8-week intervention period are presented
in Tables 3 and
4. Relative to controls,
the stairclimbing group showed a significant increase in predicted
VO2max (p < 0.05). No other significant changes
were noted.
|
| DISCUSSION |
The findings of this study demonstrate that a
low volume stairclimbing intervention can lead to favourable
changes in VO2max, but not to improvements in metabolic
or morphological fitness among sedentary middle-aged office
workers.
In the present study, a significant increase in predicted VO2max
of 9.4% was recorded in the stairclimbing group. Such an improvement
is consistent with previous exercise training literature (Pollock
et al., 1998) and may appear unexceptional. However, it is noteworthy
that this improvement in cardiorespiratory fitness was associated
with relatively low volumes of exercise. Stairclimbing training
of approximately 6 minutes per day resulted in a similar improvement
in VO2max as walking for 45 min per day (Duncan et
al., 1991). Furthermore, continuing this level of training by a
further 4-6 weeks has been shown to further improve VO2max
(Fardy and Ilmarinen, 1975), and in the case of very unfit men by as much as 25%
(Ilmarinen et al., 1979). It therefore appears that short bouts of endurance training
performed at the high end of the intensity zone recommended
for cardiorespiratory conditioning (Pollock et al., 1998) can elicit similar improvements in VO2max
as endurance training performed at low-moderate intensities
for longer durations. The duration of the training bout may
therefore be relatively insignificant to the overall training
effect of a programme designed to improve cardiorespiratory
fitness relative to the frequency and, especially, the intensity
of training (Shephard, 1968).
An inevitable consequence of a sedentary way of life is a low
level of cardiorespiratory fitness, thus such individuals have
the greatest potential for absolute and relative increases in
fitness (Wenger and Bell, 1986). Nonetheless, it continues to surprise many health professionals
that low volumes of training such as 30 minutes of exercise
once per week (Gettman et al., 1976) or 10 min of exercise 3 times per week will also significantly
improve cardiorespiratory fitness in previously sedentary individuals
(Wilmore et al., 1970), albeit to a lesser degree. In sedentary individuals
the minimum threshold to exhibit a cardiorespiratory training
effect is extremely low (Shephard, 1968). Furthermore, a number of studies have examined the training
effects of several short bouts of exercise versus one long session
per day (Ebisu, 1985; Macfarlane et al., 2006; Murphy and Hardman, 1998; Woolf-May et al., 1999). In relation to changes in cardiorespiratory fitness,
limited evidence shows that short bouts are just as effective
as those comprising of longer sessions (Hardman, 2001). Therefore, stairclimbing can be promoted within the
typical urban working environment as proven method of improving
cardiorespiratory fitness in a way that may be more easily incorporated
into an individual's lifestyle (Woolf-May et al., 1999).
The health benefits associated with the reported improvements
in cardiorespiratory fitness have not always been wholly appreciated
(Farrell et al., 1998). Indeed, it was incorrectly assumed that a physically
active lifestyle exerted its beneficial effects by simply improving
conventional risk factors such as blood pressure, insulin sensitivity,
and lipoproteins (American College of Sports Medicine, 1991). However, it has been established that low cardiorespiratory
fitness is as strong a predictor of mortality as the more conventional
modifiable risk factors, such as cigarette smoking, hypercholesterolemia,
and hypertension (Blair et al., 1996; Wei et al., 1999). A number of reports have been published over the past
two decades on the relationship between cardiorespiratory fitness
and mortality from all causes and cardiovascular disease in
particular (Blair et al., 1998; Erikssen et al., 1998). Although the genetic component of the inter-individual
variation in VO2max is somewhere between 25% and
40% (Bouchard and Perusse, 1994), the level of physical activity is regarded as the principal
determinant of cardiorespiratory fitness (Ĺstrand and Rodahl,
1986; Powell et al., 1987). Additionally, research findings that report training
gains of up to 30% (Holly and Shaffrath, 1998),
the rapid detraining related losses (Coyle, 1998) and the natural regression associated with the aging
process (Lemura et al., 2000) illustrate not only the plasticity of cardiorespiratory
fitness but the requirement of life-long physical activity (Lamonte
et al., 2000; U.S. Department of Health and Human Services, 1996). In view of the fact that the majority of benefit
transpires when an individual moves forward from the lowest
to a slightly greater level of cardiorespiratory fitness (Blair
et al., 1995; Erikssen et al., 1998), modest amounts of stairclimbing may therefore be one
of the most time efficient methods of improving and maintaining
the health of sedentary individuals.
There is broad agreement that physical activity has significant
effects on CHD risk factors other than VO2max, such
as body mass index, blood pressure and lipoprotein concentrations
(Franklin et al., 2000).
The volume of exercise performed in the present study was relatively
low and of a type that could be easily integrated into many
individuals' daily routine, factors that are likely to have
the added benefit of greater compliance (Woolf-May et al., 1998;
1999). However, in terms of the effectiveness of stairclimbing
to reduce the risk of CHD by improving indices of body composition,
blood pressure and lipoprotein concentrations, the results were
not supportive. The failure to observe significant changes in
these parameters with concomitant increases in cardiorespiratory
fitness is in agreement with other physical activity interventions
(Asikainen et al., 2003;
Grandjean et al., 1996;
Hinkleman and Nieman, 1993;
Stensel et al., 1994;
Woolf-May et al., 1998).
Factors that may explain the non-significant results obtained
in the current study are numerous. The most important of these
are exercise intensity, duration, frequency, length of training
programme, initial fitness level, pre-training lipoprotein levels,
weight, body fat percentage, age and gender, and socio-economic
factors. Cognisant of these multiple factors, the conclusions
drawn must therefore be limited to the population the participants
represent and the specific conditions under which the study
was conducted (Gaesser and Rich, 1984).
Nonetheless, the salient factor appears to be the extremely
low training volume. Although the minimum effective volume of
training for coronary risk factors such as body composition,
blood pressure and lipoprotein concentrations is unknown (Asikainen
et al., 2003),
it appears to be greater than the estimated 287 kcal·week-1
used in the current study (Franklin et al., 2000).
The somewhat arbitrary range of 1000-1500 kcal·week-1
is gaining some acceptance as a threshold for change (Asikainen
et al., 2003;
Durstine et al., 2001;
Leon and Sanchez, 2001)
and is reflected in current physical activity guidelines (Pate
et al., 1995;
U.S. Department of Health and Human Services, 1996). However, it should be noted that volumes of
training as low as 500 kcal·week-1 are recognized
to have some beneficial effects on all-cause mortality (Kohl,
2001;
Lee and Skerrett, 2001)
and walking for as little as 60 minutes·week-1 has
been shown to reduce CHD risk in women (Lee et al., 2001).
The optimal pattern of physical activity to obtain health benefits
and the associated mechanisms is therefore by no means a resolved
issue and has been previously debated (Despres and Lamarche,
1994;
Pate et al., 1995;
U.S. Department of Health and Human Services, 1996; Winett and Carpinelli, 2000). |
|
| CONCLUSION |
| In summary, regular stairclimbing selected for
its widespread applicability, has been shown to positively enhance
an important component of health-related fitness, namely cardiorespiratory
fitness. Our findings however do not support the suggestion that a
low volume stairclimbing modifies body composition, blood pressure
or lipoprotein concentrations in middle- aged men and women and strengthens
the argument for additional research into alternative mechanisms that
might mediate the effect of stairclimbing on the risk of CHD. |
| ACKNOWLEDGMENT |
| The authors thank the participants for their time
and efforts. |
| KEY
POINTS |
- Low
volumes of stairclimbing significantly increased a key component
of cardiorespiratory fitness, namely VO2max.
- Stairclimbing
can therefore be promoted within the typical urban workplace as
a health enhancing activity.
- Indices
of morphological or metabolic fitness may require larger volumes
of stairclimbing than as prescribed in the current study.
|
| AUTHORS
BIOGRAPHY |
Rodney A. KENNEDY
Employment: School of Sports Studies, University of Ulster,
Jordanstown, County Antrim, BT37 OQB, United Kingdom.
Degree: PhD.
Research interests: Physical activity, exercise and health.
E-mail: r.kennedy@ulster.ac.uk
|
|
Colin
A.G. BOREHAM
Employment: Institute for Sport and Health, University College
Dublin, Belfield, Dublin 4, Ireland.
Degree: PhD.
Research interests: Physical activity, exercise and health.
E-mail: Colin.Boreham@ucd.ie
|
|
Marie
H. MURPHY
Employment: School of Sports Studies, University of Ulster,
Jordanstown, County Antrim, BT37 OQB, United Kingdom.
Degree: PhD.
Research interests: Walking and health.
E-mail: mh.murphy@ulster.ac.uk |
|
Ian
S. YOUNG
Employment: Department of Clinical Biochemistry, Institute
of Clinical Science, Queen's University, Belfast, BT12 6BJ,
United Kingdom.
Degree: MD.
Research interests: Oxidative stress in disease.
E-mail: I.Young@qub.ac.uk |
|
Nanette
MUTRIE
Employment: Department of Sport, Culture and Arts, Strathclyde
University, Glasgow, G13 1PP.
Degree: PhD.
Research interests: Physical activity and mental health.
E-mail: nanette.mutrie@strath.ac.uk
|
|
|
|
|
