Heart-Rate Response of Elderly Women to Nonweightbearing Ambulation with a Walker
INGRID M. BARUCH
and KURT A. MOSSBERG
The purpose of this study was to determine the heart-rate reponse to nonweightbearing ambulation with a walker in a group of active, healthy 60- to 80-year-old
women. The subjects walked for three minutes over a smooth-surfaced tile track
using a three-point nonweight-bearing gait at a self-paced rate. Heart rate was
monitored by biotelemetry at rest, during the last minute of exercise, and for the
first five minutes of recovery. The mean velocity of ambulation with a walker
selected by this group was 12 ± 5 m/min. Mean heart rate increased 49 ± 14
bpm during the third minute of activity over the mean resting rate of 77 ± 8
bpm. Group heart rates rose to an average of 83 percent of their age-predicted
maximum heart rate. All subjects achieved steady-state heart rate during the
third minute of walking. This study suggests that an excessive amount of cardiac
work may be demanded of the elderly individual during walker use. This stress
on the heart is a major source of concern to the physical therapist whose goal
is to provide a safe and effective therapeutic program for the geriatric patient.
Key Words: Gait, Geriatrics, Heart rate, Physical therapy.
Gait training with various assistive devices has
been described as vigorous and brief, intense exercise1
and has long been studied in terms of its stress on the
heart of an individual performing such a task. 2 ' 3
However, investigation of the stress of walker use is
a topic that has received little attention in the literature. Many physical therapists may not be aware of
just how much is demanded of the cardiovascular
system when an elderly patient receives gait training
with a walker.
A variety of physiological and pathological changes
associated with aging create a general condition of
instability and weakness that warrants the use of an
assistive device to aid in performing functional walking. Although the walker is the gait aid most frequently used for the unstable elderly patient who
needs extra support and security during walking,4
only one published report has been found that studied
the stress of using a walker on an elderly population. 2
Cordrey and colleagues in 1958 compared energy
expenditure of 20 patients, 50 to 87 years of age, who
were asked to walk with axillary crutches, in parallel
Ms. Baruch was a student in the master's degree program in
physical therapy, Texas Woman's University, Houston, TX, when
this study was conducted. She is now a physical therapist in the state
of New York and resides at 50-45 184 St, Fresh Meadows, NY 11365
(USA).
Mr. Mossberg is an instructor at Texas Woman's University,
School of Physical Therapy, Houston, TX 77030.
This paper was submitted February 7, 1983; was with the authors
for revision six weeks; and was accepted June 28,1983.
1782
bars, or with a walker using either a nonweightbearing (NWB) or partial weightbearing (PWB) gait.
No significant differences between the oxygen consumption of the various modes of ambulation were
found, although use of the walker in a NWB gait
resulted in the greatest increases in heart rate.
In the only other study found of walker use, Harsh
in 1982 studied oxygen consumption in a group of 25
young females, 19 to 30 years of age, using a NWB
gait with axillary crutches and with a walker (unpublished data, FL Harsh, 1982). When Harsh considered
velocity of ambulation, she found that use of the
walker required a significantly higher level of oxygen
consumption than use of the crutches. This study
demonstrated that at the same rate of energy expenditure, crutch users could ambulate a greater distance
than the walker users.
Most of the studies of energy expenditure during
specific tasks have been carried out by measuring
oxygen consumption. This technique requires the collection of expired air with the Douglas bag apparatus.
Its use is impractical, however, in a clinical setting,
especially with the aged, handicapped children, or
anyone who might become anxious while using such
a cumbersome contraption. 5 In an elderly group
tested with the face mask and Douglas bag system,
many were unable to tolerate the mouthpiece, and
some panicked because of a feeling of lack of air.6
Because heart rate has been shown to be linearly
related to oxygen uptake and energy cost at submaxPHYSICAL THERAPY
RESEARCH
imal work loads, researchers have proposed heart rate
as a valid and reliable index of exercise intensity
under controlled conditions.7 (pp344-355),8 In addition,
heart rate is considered to be a valid indicator of the
work performed by the heart in response to
exercise.9(p51) Many researchers have adopted guidelines for the use of heart-rate responses as indicators
of levels of safe and tolerable exercise intensities in
relation to age and physical condition. Some guidelines call for monitoring actual heart rate attained
during the exercise,10 and then reporting the percent
of the age-predicted maximum heart rate attained. 9(pp2-4),11,12 (pp22-24) Other methods including
using predetermined standard heart-rate values at
which activity is considered too strenuous2,13,14 and
tables listing functional work-load intensity by heartrate response.10,15,16
Determining the cardiovascular stress of walker use
is needed to provide safe and effective gait training to
elderly patients. The purpose of this study was to
determine the heart-rate response to NWB ambulation with a walker in a group of active, apparently
healthy, 60- to 80-year-old women.
METHOD
Subjects
Twenty-five women between 60 and 80 years of
age with no history of cardiovascular, respiratory, or
major musculoskeletal abnormalities consented to be
studied. No subject was under a physician's care or
taking prescribed medication for any of the abovementioned conditions. The subjects solicited were
from various hospital volunteer organizations in the
Texas Medical Center and other community volunteer organizations from the surrounding area. Participants were asked not to consume food and beverages
other than water for at least two hours before testing.
Smoking was prohibited at least 30 minutes before
the exercise.
Equipment
Heart rate was monitored using a Narco Biotelemetry unit* and recorded by a desk model Physiograph®.† Electrode sites were cleansed with alcoholsoaked gauze pads. Conductive gel and tape were
used to ensure good contact between the monitoring
electrodes and the subject's skin. An adjustable adult
aluminum four-point walker was the ambulatory assistive device. As each subject walked at a self-selected
comfortable pace for the three-minute exercise, we
* Model FM-1100-E2 and FM-1100-6, Narco Bio-Systems, Inc,
Houston, TX, 77061.
† Model DMP-4B, Narco Bio-Systems, Inc, Houston, TX, 77061.
Volume 63 / Number 11, November 1983
measured velocity with a stopwatch and a tape measure.
Procedure
The protocol for this research had been approved
by a Human Subjects Review Committee and by a
separate committee composed of faculty members
from the Department of Physical Therapy of Texas
Woman's University. After the subject had arrived at
the testing area, we explained the procedure and the
subject signed a consent form. Subjects were reminded before the experiment that if at any time
during the walk, they felt short of breath, excessive
fatigue, or too much discomfort, the experiment
would be stopped immediately and the subject would
be under no obligation to complete the task.
The walker was fitted to the subject in the standing
position. With the walker approximately 30 cm (1 ft)
in front of the subject, the height was adjusted so that
there was an approximate angle of 30 degrees of
elbow flexion when the hands were placed on the
walker and the shoulders were relaxed. Instructions
and demonstration of the three-point NWB gait were
given, but subjects did not receive training sessions
before the experiment. The women were allowed to
select whichever leg was most comfortable for weight
bearing, but they could not switch legs at any time
during the exercise.
The subject was then prepared for electrode placement. We cleansed the areas over the manubrium and
the fifth intercostal space with alcohol and gauze until
slight erythema occurred. The silver disk electrodes,
filled with electrode gel, and the telemetry transmitter
were placed and secured by tape. After the subject
rested for five minutes in a sitting position, we obtained resting heart-rate values. Following the rest,
the subjects ambulated with the walker at a comfortable but steady pace using the NWB gait for three
minutes over a smooth-surfaced tile track. Heart rate
response during the last minute of exercise (actual
number of ECG cycles during 60 seconds) and during
each of the first five minutes of the recovery phase
were recorded by the physiograph. Measurement of
the velocity of the walk was determined as distance
covered over the three-minute period in meters per
minute.
Analysis
We used a descriptive design to gather data. Means
of group age, resting heart rate, exercise heart rate
during the third minute of ambulation, and velocity
in meters per minute were calculated. We reported
heart-rate response during the third minute of ambulation in several ways. First, we determined mean
increases in the heart rate reported in beats per minute
1783
HR ex
Subject
Age
(yr)
HR rest
(bpm)
HRex
(bpm)
HR max
minus
(220-age)
HR rest
(bpm)
Percent
Increase
Of HRex
over
HR rest
Walker Ambulation for Three Minutes
Percent
of
HR max
Reached
1
60
80
110
160
30
38
69
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
64
80
72
72
70
73
63
60
64
70
75
69
73
62
73
66
72
71
65
61
61
70
65
68
80
69
76
68
65
74
76
92
89
84
67
62
70
84
70
81
90
82
82
88
78
70
78
78
132
150
108
135
111
129
118
128
128
124
136
96
107
148
124
135
151
124
129
116
137
114
112
144
156
140
148
148
150
147
157
160
156
150
145
151
147
158
147
154
148
149
155
159
159
150
155
152
52
81
32
67
46
55
42
36
39
40
69
34
37
64
54
54
61
42
47
28
59
44
34
66
65
117
42
99
71
74
55
39
44
48
103
55
53
76
77
67
68
51
57
32
76
63
44
85
85
107
73
91
74
88
75
80
82
83
94
64
73
94
84
88
102
83
83
73
86
76
72
95
HRrecov
after
5 min
(bpm)
TABLE 1
Data for Twenty-Five Women (Ages, 60 to 80) Performing Nonweight-bearing
not
measured
92
82
81
80
66
91
77
85
91
85
79
69
73
86
86
95
91
87
92
96
90
75
79
85
Distance
Traveled
(m)
Velocity
(m/min)
39.0
13.0
30.5
24.1
14.3
57.6
33.8
28.4
24.1
31.4
20.1
32.3
30.8
24.7
30.8
63.7
41.2
32.9
44.2
36.6
36.6
27.1
94.5
28.1
30.5
48.8
10.2
8.0
4.8
19.2
11.3
9.5
8.0
10.5
6.7
10.8
10.3
8.2
10.3
21.2
13.7
10.9
14.7
12.2
12.2
9.0
31.5
9.4
10.2
16.3
above the resting level. Second, we calculated mean
percent increases over resting values, and third, we
derived percentage of the age-predicted maximum
heart rate (220 minus the age in years).7 (pp189-191),
9 (pp2-4)
Variability within the group was described for
the above characteristics by calculating standard deviations and reporting the ranges.
returned to within 5 bpm of their resting heart rates
during the first five minutes of the recovery period.
On the average, the group traveled 36 m (117 ft)
during the three-minute walk resulting in a self-selected mean speed of 12 ± 5 m/min.
RESULTS
Nonweight-bearing use of a walker elicited heartrate responses that were considered excessively high
in most of the elderly women studied.
In studies that have investigated activities similar
to NWB use of a walker, reports of excessive stress
on the cardiovascular system have been emphasized.
In Cordrey's study of 20 elderly patients with femoral
fractures who ambulated with a walker, with axillary
crutches, or in parallel bars, use of a walker with a
NWB gait elicited pulse rates that were almost twice
that observed in patients using the other assistive
devices.2
In two separate studies of unilateral amputees using
either their prostheses or axillary crutches, Erdman
and colleagues17 and Ganguli and Datta5 found that
the static component of weight support by the upper
extremities involved in walking with crutches, especially with a NWB gait, resulted in a heavy load
placed on the heart. Even in groups of healthy young
Raw scores for each individual are listed in Table
1. The descriptive results of this study are summarized
in Table 2.
The mean age for the group was 68 ± 5 years
(range, 60 to 80 years). Mean resting heart rate was
77 ± 8 bpm. Group mean for heart rate reached
during the third minute of exercise was 125 ± 15
bpm. By comparing the number of heart beats during
the second half of the third minute with the number
of heart beats during the first 30 seconds of that
minute, we determined that every subject had reached
steady state by the end of the three-minute task. The
work performed resulted in a mean increase of 64 ±
21 percent (49 ± 14 bpm) over the resting heart rate.
This walking task elicited a heart-rate increase equal
to 83 ± 11 percent of the age-predicted maximum
heart rate. The heart rates of 12 of the 25 subjects
1784
DISCUSSION
PHYSICAL THERAPY
RESEARCH
TABLE 2
Summary of Descriptive Data Related to Nonweight-bearing Use of a Walker in Twenty-five Elderly Women
Age
(yr)
HR ex a
(bpm)
HRrest
(bpm)
HRex minus Percent InHRrest (bpm) crease of
HRex over
Percent of
HRmaxb
Velocity
(m/min)
Reached
HRrest
Mean
Standard deviation
Range
a
b
67.9
5.3
77.3
8.2
125.8
14.5
48.5
14.1
63.9
21.4
82.9
10.5
60-80
62-92
96-151
28-81
32-117
64-107
11.9
5.4
4.8-31.5
HRex = heart rate response during the third minute of exercise.
HRmax = 220 minus the age in years.
adults, use of the swing-through and NWB gait patterns with axillary crutches at various speeds resulted
in excessively high heart rates.18,19
Unfortunately, we cannot compare our work with
others' because relatively few studies of the elderly
performing gait activities have been conducted. Acquiring a sufficiently large control group from the
elderly population is difficult because in addition to
their intolerance to many of the common testing
procedures described earlier, many elderly people
cannot be selected as subjects because they take medications or have varying degrees of physical and
mental disabilities.
Yet, study of older individuals is of vital importance because with advancing age, cardiopulmonary
function declines and physical strength and the ability
to sustain strenuous exercise are gradually reduced.20
The older person, when asked to perform rehabilitative exercise, is carrying much more of a burden than
the young, healthy, physically active individual asked
to perform the same task. The present study was
designed, therefore, to investigate the heart-rate response to NWB ambulation with a walker in a group
of normal, apparently healthy, elderly individuals.
Four major factors (systolic arterial pressure, left
ventricular size, heart rate, and contractility) determine myocardial oxygen demand and the work performed by the heart. Of these factors, heart rate is
most easily monitored. With the use of radiotelemetry, which is easily attached to the patient and allows
freedom of movement throughout the activity,21 heart
rate is now considered to be a direct, simple, accurate,
and highly reliable means of assessing the intensity
of an exercise protocol in a clinical setting.5,22
Because many researchers have defined various
ways of assessing exercise stress according to heartrate response, a comparison of the results of the
present study with the results of others is of interest.
Several authors have stated that when heart rate has
exceeded 120 bpm in response to exercise, the activity
should be stopped.2,14 The mean heart-rate response
to the NWB walker exercise was 126 bpm; 16 out of
the 25 subjects exceeded a heart rate of 120 bpm. The
World Health Organization has recommended that in
Volume 63 / Number 11, November
1983
persons over 60 years of age, cessation of exercise
should occur when heart rate has reached 130 bpm.13
Of the 25 women studied, 9 exceeded these limits.
According to Grandjean, most investigators in the
field of exercise physiology agree that the optimum
limit of work performance is reached when the average pulse rate during work is approximately 30 bpm
over the resting level.10 Twenty-three of the 25 subjects produced heart rates that exceeded this limit in
response to three minutes of work with the mean
increase over the resting level at 49 bpm.
Determining a target heart rate during graded work
based on age-predicted maximum heart-rate values
has been widely used in many exercise rehabilitation
programs.11,12 (pp22-24) These training heart-rate ranges
represent an estimate of the safest effective training
intensity. Amundsen has stated that at intensities of
exercise that increase heart rate to a maximum of 60
to 75 percent of the age-predicted maximum heart
rate, the patient should be able to reach and maintain
steady-state conditions for 20 minutes or more.9 (pp2-4)
Based on calculations of these levels in the subjects
under study, the mean percent of maximum heart
rate (HRmax) reached during the third minute of
exercise was 83 percent. Only two subjects were able
to stay below the 70 percent mark during this activity.
Most subjects reached between 70 and 95 percent of
their HRmax levels. Two subjects even exceeded 100
percent of their age-predicted HRmax levels. These
results strongly indicate that NWB walker ambulation
is a stressful activity in regard to its work demands
on the heart.
Still another means of interpreting these results is
based on tables of work-load classification according
to heart rate. Buskirk has categorized "heavy" work
as that which elicits a heart-rate response between
120 and 140 bpm and "very heavy" work as causing
responses of 140 to 160 bpm.15 Thus, this task caused
12 subjects to perform heavy work and 4 subjects to
perform very heavy work. If one looks at activities
categorized as "heavy" work according to heart rate,
oxygen consumption, and metabolic equivalent level
(METS), the stress that may be placed on the person
who must use a walker with a NWB gait pattern is
1785
emphasized. Twelve subjects performed work comparable to heavy shoveling and carrying objects
weighing between 60 and 90 lbs.9(p26) The problem
encountered with the use of these work-load classification tables is that no listing is made of the duration
of exercise related to these heart-rate responses or the
age group for which these levels apply. Robinson,
however, in a study of healthy older men observed
that during an exercise routine that he described as
"exhaustive," heart-rate responses ranged from 130
to 150 bpm after three minutes of exercise.16 Thus, by
Robinson's standards, nine of the subjects in our
study performed exhaustive activity during NWB
ambulation with a walker.
The heart rates of only 12 out of the 25 subjects
returned to within 5 bpm of their resting levels during
the first five minutes of the recovery phase. This
finding is also indicative of a high level of exercise
intensity because the time required for the heart rate
to return to normal after exercise depends on the
fitness level of the individual and the severity of the
work.9(p8)
The subjects in this study were all instructed to
walk at a comfortable but steady pace for the threeminute task. We chose self-selected velocity because
a subject walking at a comfortable or natural speed
will adopt a velocity comparable to the one at which
minimal energy expenditure occurs.23 The use of a
naturally selected speed provides baseline data for
comparison of these results with those of physically
disabled people who can walk only at self-selected
rates. A study by Blessey and colleagues in 1976
determined that 20- to 60-year-old healthy women
who performed unrestrained or "free" walking chose
74 m/min as their mean comfortable speed.24 Although the subjects in the present study were older,
the intensity of the NWB walker activity may be
emphasized by the slowness of the mean velocity of
12 m/min selected by the group; this is considerably
slower than normal walking.
The task length of three minutes is considered to
be a functional duration that would be used by an
elderly patient (time needed to walk to the bathroom
from their bed or walk outside to a car). The mean
distance walked during the three-minute exercise was
36 m (117 ft), which is quite close to the distance
commonly attained in physical therapy departments
during ambulation training. The task was of short but
functional duration, and the women were allowed to
move at their own pace. Their slow speed and high
heart-rate responses indicate that the activity was a
costly one in terms of energy expenditure.
1786
The picture is complicated even further when the
whole condition of the patient is taken into consideration. In addition to the normal decline in the
efficiency of the cardiovascular system with aging,
the hospitalized patient experiences heightened anxiety and cardiac stress because of the unfamiliar
surroundings, in addition to the physical and mental
discomfort resulting from their disease or injury. Another factor that must be considered when applying
these results to a patient population is the potential
effect of medication on heart-rate response. Also, the
detrimental effects of bedrest alone on the physical
condition of an individual have been well documented.22'25
This investigation focused on one group of relatively active and healthy 60- to 80-year-old women.
Future studies using a larger group of subjects whose
physical condition more closely resembles that of the
elderly hospitalized patient would be informative. A
measurement of the rate-pressure product (heart rate
multiplied by systolic blood pressure) during gait
activities such as walker ambulation would be helpful
in providing a more accurate picture of the myocardial work demanded during such exercises.12(p9) Another area for research would be a study to determine
whether receiving a training program using the upper
extremities before ambulation training would affect
the subject's heart rate response during gait. Comparison of the energy required of the elderly individual
using different ambulation aids (crutches, walker, or
wheelchair) is also an area in need of investigation.
CONCLUSION
Because the subjects involved in this study were
healthy women with no history of cardiovascular
disease, the results suggest that an elderly patient who
may have some degree of cardiac dysfunction is at
risk of developing cardiac intolerance during a therapeutic activity such as NWB use of a walker. Physical therapists must be more aware of how stressful
certain therapeutic exercises actually may be and how
patients can easily be monitored during potentially
hazardous rehabilitative activities. Teaching the patient to monitor pulse rate independently with a
simple measure before and after exercise may be
sufficient.22 Physical therapists have a responsibility
to recognize and prevent intolerance to exercise,
thereby minimizing the risks of physical exercise and
guiding each patient in selecting a safe, yet beneficial,
level of activity during treatment.
PHYSICAL THERAPY
RESEARCH
REFERENCES
1. Amundsen LR: Assessing exercise tolerance: A review. Phys
Ther 59:534-537, 1979
2. Cordrey LF, Ford AB, Ferrer MT: Energy expenditure in
assisted ambulation. Journal of Chronic Diseases 7 : 2 2 8 233, 1958
3. Fisher SV, Gullickson G: Energy cost of ambulation in health
and disability: A literature review. Arch Phys Med Rehabil
5 9 : 1 2 4 - 1 3 3 , 1978
4. Steinberg FU: Gait disorders in old age. Geriatrics 2 1 : 1 3 4 143,1966
5. Ganguli S, Datta SR: Prediction of energy cost from peak
heart rate in lower extremity amputees. J Med Eng Technol
10:52-55, 1975
6. Kavanagh T, Shephard RJ: The application of exercise testing to the elderly amputee. Can Med Assoc J 108:314-317,
1973
7. Astrand PO, Rodahl K: Textbook of Work Physiology, ed 2.
New York, NY, McGraw-Hill Inc. 1977
8. deVries HA: Prescription of exercise for older men from
telemetered exercise heart rate data. Geriatrics 2 6 : 1 0 2 111,1971
9. Amundsen LR (ed): Cardiac Rehabilitation. New York, NY,
Churchill Livingstone Inc, 1981
10. Grandjean E: Fitting the Task to the Man. London, England,
Taylor & Francis Ltd, 1971, pp 5 3 - 5 6
11. American College of Sports Medicine: Guidelines for Graded
Exercise Testing and Exercise Prescription, ed 2. Philadelphia, PA, Lea & Febiger, 1980, pp 3 9 - 4 8
12. The Committee on Exercise: Exercise Testing and Training
of Apparently Healthy Individuals: A Handbook for Physicians. Dallas, TX, The American Heart Association, 1972, pp
9, 2 2 - 2 4
13. Anderson KB, Shephard RJ, Denolin H, et al: Fundamentals
of Exercise Testing. Geneva, Switzerland, World Health Organization, 1971, pp 4 5 - 4 6
Volume 63 / Number 11, November 1983
14. Tobis JS, Zohman LR: A rehabilitation program for patients
with recent myocardial infarction. Arch Phys Med Rehabil
49:443-448, 1968
15. Buskirk ER: An introduction to exercise and performance
evaluation. JSC Med Assoc 65 (Suppl):4-7, 1969
16. Robinson S: Experimental studies of physical fitness in relation to age. Arbeitsphysiologie 10:251-323, 1938
17. Erdman WJ, Hettinger T, Saez F: Comparative work stress
for above-knee amputees using artificial legs or crutches.
Am J Phys Med 3 9 : 2 2 5 - 2 3 1 , 1960
18. Sankarankutty M, Stallard J, Rose GK: Relative efficiency of
'swing-thru' gait on axillary, elbow and Canadian crutches
compared to normal walking. J Med Eng Technol 1:55-57,
1979
19. Patterson R, Fisher SV: Cardiovascular stress of crutchwalking. Arch Phys Med Rehabil 62:257-260, 1981
20. Harris R, Frankel LF, Harris S: Guide to Fitness after Fifty.
New York, NY, Plenum Publishing Corp, 1977, pp 5 - 1 0
2 1 . Clarke CP, Itoh M, Solomon M, et al: Radioelectrocardiogram
monitoring during ambulation training of patients with amputations. Phys Ther 51:906-913, 1971
22. Lunsford BR: Clinical indicators of endurance. Phys Ther
58:704-709, 1978
23. Bassey EJ, Fenten PH, MacDonald IC: Self paced walking
as a method for exercise testing in elderly and young men.
Clinical Science and Molecular Medicine 5 1 : 6 0 9 - 6 1 2 , 1 9 7 6
24. Blessey RL, Hislop HJ, Waters RL, et al: Metabolic energy
cost of unrestrained walking. Phys Ther 56:1019-1024,
1976
25. Saltin B, Blomqvist B, Mitchell JH, et al: Response to exercise
after bedrest and after training. Circulation 38(Suppl 7 ) : 1 78, 1968
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