The International Journal of Psychosocial Rehabilitation

Study on the Perceived Exertion during a Graded Exercise
 Test in Patients with Depressive and Anxiety Disorders


    J Knapen
 
D Vancampfort

J Raepsaet

M Probst 


Faculty of Kinesiology and Rehabilitation Sciences
Katholieke Universiteit Leuven, Tervuursevest 101, 3001 Leuven, Belgium
University Psychiatric Centre K.U.Leuven, Campus Kortenberg, Leuvensesteenweg 517, 3070 Kortenberg, Belgium


Citation:
Knapen J, Vancampfort D, Raepsaet J, & Probst M (2012). Study on the Perceived Exertion during a Graded Exercise Test in Patients
with Depressive and Anxiety Disorders
 International Journal of Psychosocial Rehabilitation. Vol 16(1) 44-51


Corresponding author:
Jan Knapen
University Psychiatric Centre K.U.Leuven, Campus Kortenberg
Leuvensesteenweg 517
3070 Kortenberg,
Belgium
Mail: jan.knapen@faber.kuleuven.be

Acknowledgements
The authors thank the patients who participated in the study and the physiotherapists for the evaluation of the physical fitness and the data collection. They have no conflicts of interest that are directly relevant to the content of this manuscript.


Abstract
Purpose: The aim of the present cross-sectional study was to explore which variables could explain the perceived exertion during a graded exercise test (GXT) in patients with depressive and anxiety disorders. Method: In three treatment units of a university psychiatric hospital in Belgium, 137 patients (49 males and 88 females) performed a submaximal GXT the first week of admission. The rate of perceived exertion (RPE) at 60% of the maximal heart rate reserve (MHRR) was measured by means of the Borg Category Ratio 10 Scale. Depression, anxiety, level of physical activity and perceived cardio-respiratory fitness were evaluated by means of questionnaires. The motivation towards exercise therapy was measured using a visual analogue scale. A linear multiple regression equation was used to ascertain the explaining variables for the perceived exertion. Results: The explaining variables for RPE at 60% of MHRR, in order of importance, were age, level of physical activity and state anxiety. Conclusions: Patients who are older, less active and/or patients with a high anxiety level perceive a high RPE during a GXT. These findings should be taken into account in the use of exercise tests and exercise prescriptions for depressed and anxious psychiatric patients.



Introduction
Physical (in)activity might be important for physical and mental health [1,2]. In general, patients suffering from depressive and anxiety disorders exhibit a more sedentary lifestyle and this results in a low level of fitness [3-7] and a poor physical health [8-10]. This is a first argument for the implementation of exercise therapy within comprehensive treatment programmes for these patients. Another argument is the therapeutic effect of regular exercise on severity of depression and anxiety [11-13]. Well-designed exercise therapy programmes for these patients require a measurement of their physical fitness and perceived exertion [5].

Direct measurement of maximal oxygen intake by way of a maximal exercise test is the most accurate indicator of cardio-respiratory fitness. Maximal tests, however, have the disadvantage of requiring the subject’s optimal motivation to work to ‘near exhaustion’, and need the supervision of a physician and the use of expensive equipment [14]. In exercise therapy for psychiatric patients, however, submaximal measures are highly recommended because many patients have a poor physical health, low levels of fitness and physical self-confidence, few experiences with aerobic training, and less energy and motivation for heavy physical effort [4]. These clinical considerations usually lead to the application of submaximal exercise tests in exercise therapy programmes. Craft and Landers [15] concluded in a meta-analytic review of studies on the effects of exercise on clinical depression that submaximal measurements are common in psychiatric settings; 18 of 20 surveys used submaximal exercise tests.

A high level of perceived exertion during exercise is negatively associated with participation in physical activity [16]. When the effort perceived by an individual increases, so too does the chance of drop-out. For depressed and anxious patients who often exhibit a high level of fatigue and a low motivation towards physical exercise, the rate of perceived exertion (RPE) is an important parameter when designing an appropriate exercise programme [5]. Generalised fatigue and lack of energy are typical symptoms of the depressive syndrome [17]. Patients with anxiety disorders might fear that aerobic effort will provoke physiological reactions such as shortness of breath, tachycardia, dizziness or sweating, which they associate with symptoms of panic attacks [4,5]. The RPE is a valuable tool in teaching these patients to monitor exercise intensity by taking account of their own level of fatigue and pain, rate of breathing and muscular sensations.

Most commonly, the evaluation of degree of perceived exertion can be derived from the psychophysiological concept of Borg [16,18,19]. The Borg 15 Graded Category Scale and the Borg Category Ratio 10 Scale (Borg CR 10 scale) quantify the sensations that the subject experiences during physical effort. The Borg 15 Graded Category Scale has a score range from 6 to 20 (15 grades), and the Borg CR 10 scale from 0 to 10 (10 grades). Both scales show a linear relationship with heart rate during progressive incremental exercise (r = 0.94 and r = 0.88, respectively).

In a previous study [20], we investigated the likelihood of drop-out during a graded exercise test (GXT) in a group of depressed and anxious psychiatric inpatients (n=124). During the course of the study, 40.3% of the patients were unable to complete the incremental GXT to 80% of the maximal heart rate reserve (MHRR). The determining variables for drop-out, in order of importance, were: the severity of depression in interaction with gender, the motivation towards exercise therapy and the body mass index (BMI). Female patients suffering from high severity of depression, less motivated patients and those patients with a higher BMI all have a higher risk of dropping out during the GXT. In this study the RPE was not included as a potential explaining variable for the drop-out.

The purpose of the present study was to investigate which psychological and physical variables could explain the perceived exertion during a GXT in patients with depressive and anxiety disorders. To the best of our knowledge, this is the first study that investigates this topic in a sample of psychiatric patients.

Methods

Subjects
During the course of the research project, 142 patients suffering from depressive and/or anxiety disorders [17] were admitted into three treatment units in a university psychiatric hospital in Belgium. All patients were asked to take part in the study; only five individuals refused. The investigated group therefore consisted of 137 patients (49 males and 88 females). Exclusion criteria were psychosis, treatment with beta-blockers and somatic disorders that would rule out any form of submaximal exercise testing. Before performing the GXT, the subjects answered the questionnaires.

Cardio-respiratory fitness
Cardio-respiratory fitness was measured by means of a submaximal incremental Graded Exercise Test (GXT) on an electronically braked bicycle ergometer (Ergo 2000) according to the Franz test [5,21]. The protocol for this test is to increase the work load by 10 Watts every minute, starting with a work load that corresponds to the body weight. Since such a work load was not feasible for many of the patients, the first stage work load was reduced by 30 Watts for male subjects and 50 Watts for the females. At the end of each stage the heart rate was registered by means of a heart rate monitor. The subjects were advised to maintain a steady pace of 60 rotations per minute. The GXT was terminated when: (a) the participant showed certain symptoms making it necessary to stop the GXT (14), (b) the subject was no longer able to maintain the pace of 60 rotations per minute, and (c) the subject reached the predetermined end point heart rate: 80% of the estimated MHRR. Patients were requested to refrain from eating, drinking coffee or smoking during a two-hour period prior to the test. After the testing every participant performed a cooling down with the same intensity in the second stage. Previous research by Knapen et al. [5] showed that the Franz test has a good reliability in a sample group of psychiatric inpatients (r ranged from 0.74 to 0.90).

Perceived exertion
For the evaluation of perceived fatigue, the short Borg CR 10 Scale [19] was chosen for the reason that the longer Borg 15 Graded Category Scale requires a greater differentiation capacity. Considering that patients were not familiar with the evaluation of perceived exertion and that Franz’s cycling test in most cases only lasts 10 minutes, the shorter test seemed more appropriate. Prior to the examination, the test leader gave clear information concerning the rating procedure and the range of the scale. At the end of each stage, patients indicated their perceived exertion. The Borg 60% at MHRR was the rate on the Borg CR 10 scale that was related to 60% of the MHRR. 

Depression
The Beck Depression Inventory (BDI) was used to evaluate the severity of depression [22]. This is a 21-item self-reporting questionnaire consisting of symptoms and attitudes relating to depression. The range of possible total scores is 0-63; with higher scores indicating greater depression. The Dutch version of the BDI has been shown to be a valid and reliable measure of depression severity [22].

Anxiety
The State Anxiety Inventory (SAI) was used to assess state anxiety [23]. This self-rating scale consists of 20 items, with response scores on a scale from one to four. The range of possible total scores is 20-80; higher scores indicate higher levels of anxiety. The SAI represents one of the most reliable and valid instruments for assessing trait anxiety in psychiatric settings, and has been validated for use in Dutch by Hermans [23].

Level of physical activity
Habitual physical activity before admission was assessed using the Baecke questionnaire [24]. Philippaerts and Lefevre [25] showed the Baecke questionnaire to be a reliable and valid instrument in the assessment of regular physical activity in a Belgian sample group.

Perceived cardio-respiratory fitness
Perceived cardio-respiratory fitness was assessed using the sub-domain scale perception of sports competence and physical condition of the Dutch version of the Physical Self-Perception Profile [26,27]. This sub-domain scale consists of 12 items which measure perceptions of sport and athletic performances, level of stamina, capacity to learn sport skills and maintain physical fitness. Each item is scored on a scale from one to four, with higher scores indicating more positive self-perceptions. The range of possible total scores is 0-48. Van de Vliet et al. [27] demonstrated an adequate reliability and validity of the Dutch version of the PSPP in a sample group of Belgian psychiatric inpatients.

Motivation for participation in exercise therapy
Motivation was assessed by means of a visual analogue scale, ranging from zero (not at all motivated) to 10 (extremely motivated).

Anthropometric measures
For the calculation of the BMI, measurements of height and weight were assessed during the first week of admission. The BMI was calculated by dividing weight by the square of height.

Statistical Analysis
A linear multiple regression equation (backward elimination method) was used to ascertain the explaining variables of the RPE at 60% of MHRR [28]. The following variables were available for selection method: depression, state anxiety, level of physical activity, perceived cardio-respiratory fitness, motivation, BMI, age and gender. The statistical significance level was set at 0.05.

Ethical Committee
The study procedures were approved by the Ethical Committee of the Faculty of Medicine of the Catholic University of Leuven in accordance with the principles of the Declaration of Helsinki of 1975, and all participants gave their informed consent.

Results
Thirteen of 137 recruited patients were not used for the multiple regression equation because of missing values. The characteristics of the sample group are presented in table 1.

Table 1 Characteristics of the sample group

Variables

Mean

± SD

Age (years)

33.51

±10.62

Borg at 60% MHRR

4.95

± 2.16

Depression

25.37

± 10.29

State Anxiety

56.97

± 12.41

Level of Physical Activity

7.30

± 1.59

Perceived Cardio-respiratory Fitness

22.36

± 6.41

Motivation

6.28

± 2.47

BMI (kg/m²)

23.68

± 4.91

The higher the score, the higher the perceived exertion, severity of depression and anxiety, level of physical activity, perceived cardio-respiratory fitness and motivation


The regression equation revealed that age was the most important explaining variable for the scores on the Borg CR 10 scale at 60% of MHRR. The second most important explaining variable was the level of physical activity, and the third was found to be state anxiety. No additional variables met the 0.05 significance level for inclusion into the model. The analysis of variance of the final model is presented in table 2.

Table 2 Analysis of variance for age, level of physical activity and state anxiety 

Table 2

Source

DF

Sum of
Squares

Mean
Square

F Value

Pr > F

Model

3

36.90379

12.30126

2.69

0.0495

Error

121

553.84421

4.57722

 

 

Corrected Total

124

590.74800

 

 

 



The parameter estimates and standard errors can be found in table 3

Table 3 Parameter estimate and standard error of age, level of physical activity and state anxiety 

Variable

DF

Parameter Estimate

Standard Error

F Value

Pr> F

Intercept

1

4.55792

1.45719

9.78

0.0022

Age

1

0.00294

0.00154

3.63

0.0592

Level of P. Activity

1

- 0.20597

0.12124

2.89

0.0919

State Anxiety

1

0.01357

0.01536

0.78

0.3785



Discussion
The aim of the present study was to explore which variables could explain the degree of perceived exertion during a GXT at 60% of the estimated MHRR in a sample group of 137 depressed and anxious psychiatric inpatients. The investigated variables were age, gender, BMI, depression, state anxiety, level of physical activity, perceived cardio-respiratory fitness and motivation towards exercise therapy. The explaining variables, in order of importance, were age, level of physical activity and state anxiety.

Age was found to be the most important explaining variable for RPE at 60% of MHRR, reflecting Borg’s finding that age is an important determinant of RPE response [16]. Similar results have been found by others. In a study of Allman & Rice [29] isometric task fatigue was evaluated considering different ages. During the intermittent contractions of the elbow flexors normalized to 60% of each subject’s maximal voluntary contraction, perceived exertion was found to be significantly greater for the old men compared to the young men. In the investigation of Navalta et al. [30] significant differences were observed for age, where older subjects perceived walking down hill more effortful than younger subjects.

The level of physical activity was the second most important explaining variable. Less active patients perceived a higher level of RPE during the GXT than more active ones. Garcin et al. [31] found a similar difference in perceived exertion during exhausting runs among individuals with high and moderate fitness levels. Likewise, Travlos and Marisi [32] also concluded that relative submaximal workloads were perceived harder by untrained subjects in comparison with trained ones.

The third most important explaining variable was state anxiety. According to Morgan [18], anxious and depressive patients make less accurate interpretations regarding bodily sensations during physical activity than healthy controls. The depressed mood and anxiety causes certain physiological reactions such as perspiration, dyspnoea, tachycardia and the linked catastrophic cognitions that influence the perceptual process [5,33]. Morgan`s [18] research demonstrated a significantly positive correlation between perceived exertion and anxiety. These findings are in agreement with the present study.

It is conceivable to suppose that the results could be generalized to patients treated in other Belgium psychiatric hospitals. The following features of the study might guarantee a certain value of generalization: (a) an unselected sample group of 142 patients of both sexes was recruited in three treatment units of a large psychiatric hospital over a period of 16 months, (b) only five individuals refused to take part in the study, and (c) the complexity of psychiatric (co)morbidity of most patients seems to be representative of those of patients who are treated in other psychiatric hospitals.

Furthermore, in the present study no distinction was made between patients with depressive or anxiety disorders. The symptoms of depression and anxiety often overlap as most (90%) patients diagnosed with depression have comorbid symptoms of anxiety disorders. Similarly, it is common that patients diagnosed with an anxiety disorder get a diagnosis of depression [34].

The present study has some methodological limitations. A first limitation was that the maximal heart rate was not measured but estimated by means of the formula: 220 minus age [14]. The estimation of the maximal heart rate allows space for an estimation error although the measurement of the maximal heart rate is not easy for such populations. Secondly, the level of physical activity was recorded in a subjective manner by questioning the patient. The questionnaire technique was applied as it is the most commonly used physical activity assessment. It is a very cheap method and easily applicable in large samples. Other methods like accelerometers and heart rate monitoring are more accurate but on the other hand expensive and difficult in a sample of 137 subjects [35]. A third limitation was the use of a less specific measurement for the severity of anxiety. The SAI measures state anxiety in different situations, not exclusively in exercise conditions. The use of more specific instruments assessing fear to move, such as the Dutch version of the Tampa Scale for Kinesiphobia [36] or the Body Sensation Questionnaire [37], would be recommended for further research. A fourth limitation was that the physiological mechanisms (lactate accumulation, hyperventilation etc.) as well as the local muscular pain sensations that are responsible for the RPE during aerobic exercise were not examined [38]. Finally, further research will be needed to include other factors relating to the RPE. In particular, the influence of smoking and the adverse effects of psychotropic drugs, especially the cardiovascular adverse effects such as tachycardia, orthostatic hypotension and dizziness, should be taken into account [39].

From this study can be concluded that physiotherapists should take into account that older patients, less active patients and/or patients with a high anxiety level perceive a high exertion during aerobic exercise. The Borg CR10 Scale is a valuable tool, especially for these patients, to learn to monitor exercise tolerance. To avoid overload of these patients, the intensities from low to moderate corresponding to a value of 3-4 (moderate to somewhat strong) on the Borg CR 10 Scale should be prescribed.


 

References:

[1] World Health Organization. Global strategy on diet, physical activity and health. Geneva: World Health Organization; 2004.

[2] Pedersen B, Saltin B. Evidence for prescribing exercise as therapy in chronic disease. Scand J Med Sci Sports 2006;16:3-63.

[3] Martinsen E, Strand J, Paulsson G. Physical fitness level in patients with anxiety and depressive disorders. Int J Sport Med 1989;10:58-61.

[4] Meyer T, Broocks A. Therapeutic impact of exercise on psychiatric diseases. Guidelines for exercise testing and prescription. Sports Med 2000;30:269-79.

[5] Knapen J, Van de Vliet P, Van Coppenolle H, Peuskens J, Pieters G. Evaluation of cardio-respiratory fitness and perceived exertion for patients with depressive and anxiety disorders: A study on reliability. Disabil Rehabil 2003a;25:1312-5.

[6] Knapen J, Van de Vliet P, Van Coppenolle H, David A, Peuskens J, Knapen K, Pieters G. The effectiveness of two psychomotor therapy programmes on physical fitness and physical self-concept in nonpsychotic psychiatric patients: a randomized controlled trial. Clin Rehabil 2003b;17:637-47.

[7] Sørensen, M. Motivation for physical activity of psychiatric patients when physical activity was offered as part of treatment. Scand J Med Sci Sports 2006;16:391-8.

[8] Fenton W, Stover E. Mood disorders: cardiovascular and diabetes comorbidity. Curr Opin Psychiatry 2006;19:421-7.

[9] Kahl K, Greggersen W, Rudolf S, Stoeckelhuber BM, Bergmann-Koester CU, Dibbelt L, Schweiger U. Bone mineral density, bone turnover, and osteoprotegerin in depressed women with and without borderline personality disorder. Psychosom Med 2006;68:669-74.

[10] Whooley M. Depression and cardiovascular disease. Healing the broken-hearted. JAMA 2006;295:2874-81.

[11] Bartholomew J, Morrison D, Ciccolo J. Effects of acute exercise on mood and well-being in patients with major depressive disorder. Med Sci Sports Exerc 2005;37:2032-7.

[12] Dunn A, Trivedi M, Kampert J, Clark CG, Chambliss HO. Exercise treatment for depression: efficacy and dose response. Am J Prev Med 2005;28:1-8.

[13] Knapen J, Van de Vliet P, Van Coppenolle H, David A, Peuskens J, Pieters G, Knapen K. Comparision of changes in physical self-concept, global self-esteem, depression and anxiety following two different psychomotor therapy programs in non-psychotic psychiatric inpatients. Psychother Psychosom 2005;74:353-61.

[14] American College of Sports Medicine (US). ACSM’s health/fitness facility standards and guidelines. 6th ed. Champaign, IL: Human Kinetics; 2006.

[15] Craft L, Landers D. The effect of exercise on clinical depression and depression resulting from mental illness: A meta-analysis. J Sport Exerc Psychol 1998;20:339-57. 

[16] Borg G. External, physiological and psychological factors and perceived exertion. In: Borg G, editor. Borg’s Perceived exertion and pain scales. Champaign, Il: Human Kinetics; 1998. p 68-74.

[17] American Psychiatric Association. Diagnostic and statistical manual of mental disorders. 4th ed. Washington: American Psychiatric Association; 1994.

[18] Morgan W. Psychological components of effort sense. Med Sci Sports Exerc 1994;26: 1071-7.

[19] Borg E, Kaijser L. A comparison between three rating scales for perceived exertion and two different work tests. Scand J Med Sci Sports 2006;16:57-69.

[20] Knapen J, Van Gool M, Van de Vliet P, Van Coppenolle H, David A, Pieters G, Peuskens J,  Knapen K. Likelihood of drop-out during a graded exercise test in non-psychotic psychiatric patients. Int J Ther Rehabil 2003c;10:305-9.

[21] Franz I. Vergleichende Untersuchungen zur Messung der PWC 170 (Comparative investigations on the measurement of the PWC 170). In: Hansen G, Mellerowicz H, editors. Internationales Seminar für Ergometrie. Berlin: Institut für Leistungsmedizin; 1972. p 136-42.

[22] Bosscher R, Koning H, van Meurs R. Reliability and validity of the Beck Depression Inventory in a Dutch college population. Psychol Rep 1986;58:696-8.
[23] Hermans D. De 'Zelf-Beoordelings-Vragenlijst' (The state-trait anxiety inventory). Gedragstherapie 1994;27:145-8.

[24] Baecke J, Burema J, Frijters J. A short questionnaire for the measurement of habitual physical activity in epidemiological studies. Am J Clin Nutr 1982;36:936-41.
[25] Phillippaerts R, Lefevre J. Reliability and validity of three physical questionnaires in Flemish males. Am J Epidemiol 1998;147:982-90.

[26] Fox K. The physical self-perception profile manual. Dekalb, Il: Office for Health Promotion, Northern Illinois University; 1990.

[27] Van de Vliet P, Knapen J, Onghena P, Fox K, Van Coppenolle H, David A, Pieters G,  Peuskens J. Assessment of physical self-perceptions in normal Flemish adults versus depressed psychiatric patients. Pers Individ Dif 2002;32:855-63.

[28] SAS Institute (US). SAS language and procedures: Usage 2, Version 6 (computer program). Cary, NC: SAS Institute; 1991. 

[29] Allman B, Rice C. Perceived exertion is elevated in old age during isometric fatigue task. Eur J Appl Physiol 2003;89:191-7.

[30] Navalta J, Sedlock D, Park K. Physiological responses to downhill walking in older and younger individuals. Journal of exercise physiology online 2004;7(6):45-51. 

[31] Garcin M, Mille-Hamard L, Billat V. Influence of aerobic fitness level on measured and estimated perceived exertion during exhausting runs. Int J Sports Med 2004;25:270-7.

[32] Travlos A, Marisi D. Perceived exertion during physical exercise among individuals high and low in fitness. Percept Mot Skills 1996;82:419-24.

[33] Broocks A, Meyer T, Bandelow B, George A, Bartmann U, Rüther E, Hillmer-Vogel U. Exercise avoidance and impaired endurance capacity in patients with panic disorders. Neuropsychobiology 1997;36:182-7.

[34] Kaplan H, Sadock B. Kaplan and Sadock's Synopsis of Psychiatry: Behavioral Sciences/Clinical Psychiatry. 9th ed. Philadelphia: Lippincott Williams & Wilkins; 2005.                               

[35] Vanhees L, Lefevre J, Philippaerts R, Martens M, Huygens W, Troosters T, Beunen G. How to assess physical activity? How to assess physical fitness? Eur J Cardiovasc Prev Rehabil 2005;12:102-14.

[36] Vlaeyen J, Kole-Snijders A, Boeren R, Van Eek H. Fear of movement/(re)injury in chronic low back pain and its relation to behavioural performance. Pain 1995;62:363-72. 

[37] Bouman T. The body sensations questionnaire. Gedragstherapie 1998;31:165-8.

[38] Dishman R, Berthoud H, Booth F, Cotman CW, Edgerton VR, Fleshner MR, Gandevia SC, Gomez-Pinilla F, Greenwood BN, Hillman CH, Kramer AF, Levin BE, Moran TH, Russo-Neustadt AA, Salamone JD, Van Hoomissen JD, Wade CE, York DA, Zigmond MJ. Neurobiology of exercise. Scand J Med Sci Sports 2006;16:470-70.

[39] Martinsen E, Stanghelle J. Drug therapy and physical activity. In: Morgan W, editor. Physical activity and mental health. Washington: Taylor & Francis; 1997. p 81-90.

 


Copyright © 2012  ADG, SA. All Rights Reserved.  
A Private Non-Profit Agency for the good of all, 
published in the UK & Honduras