JOURNAL OF SPORT & EXERCISE PSYCHOU)(jY, 1990, 12, 167-176

The Effects of Sensory Deprivation and Music on Perceived Exertion and Affect During Exercise

Stephen H. Boutcher and Michele Trenske University of Virginia

This study examined the effects of sensory deprivation and music on per- ceived exertion and affect. Volunteer women (N=24) performed three 18-min sessions on a cycle ergometer at light, moderate, and heavy workloads during which perceived exertion, affect, and heart rate were monitored. Each subject participated in a control, deprivation, and music condition. No significant differences where found in heart rate between conditions. In contrast, signifi- cantly lower perceived exertion existed during the music compared to the deprived condition at the low workload. Similarly, there was lower perceived exertion during the music compared to the control condition at the moderate workload. Also, significantly greater levels of affect were observed during the music compared to the deprived condition at the moderate and heavy work- loads. It was concluded that the influence of music and deprivation on per- ceived exertion and affect was load dependent. These results are discussed with regard to informational processing models of sensory and psychological input.

Rating of perceived exertion (WE) represents an individual's subjective assessment of work during exercise. Although much research (for overviews, see Mihevic, 198 1 ; Pandolf, 1983) has examined the effect of physiological cues on RPE (e.g., muscle strain, cardiopulmonary feedback), recent studies have sug- gested that psychological variables are also an important influence. For instance, self-presentation (Boutcher, Fleischer-Curtian, & Gines, 1988), social influence (Hardy, Hall, & Prestholdt, 1986), motivational strategies (Rejeski & Ribisl, 1980), and sex orientation (Rejeski, Best, Griffith, & Kenney, 1987) have all affected WE.

Recently, Hardy and Rejeski (1989) have suggested that other subjective states during exercise should also be measured. They have argued that although RPE represents what an individual feels during exercise, it does not reflect how a person feels. Thus, at high workloads fit and unfit individuals may report similar RPE but the fit may feel exhilarated whereas the unfit may feel uncomfortable. Rejeski and co-workers (Hardy & Rejeski, 1989; Rejeski et al., 1987) have de-

Stephen H. Boutcher and Michele Trenske are with the Department of Health & Physical Education at the University of Virginia, Charlottesville, VA 22903.

168 / Boutcher and Trenske

veloped a feeling scale (FS) to assess the affective component during exercise, which they suggest is not phenomenologically isomorphic with RPE (see Hardy & Rejeski, 1989).

To explain how psychological and physiological factors may influence RPE and affective responses, Rejeski (1985) has adapted a parallel informational processing model that had been developed in pain research (Levantha1 & Everhart, 1979). This model suggests that sensory and emotional information are precon- sciously processed in parallel. lPreconscious processing is seen as an active process that allows information to be filtered through to focal awareness. Thus, sensory information (e.g., effort sense) or affective information (apprehension caused by a heavy exercise load) can form the object of attention and determine W E or affective states during exercise. As it is difficult to focus attention on multiple sources, only a certain amount of information can be processed at a time. Rejeski (1985) has suggested that when individuals are working at near maximal aerobic capacity, phy&logical cues will predominate and will function as the most salient influence on RPE. When work is performed at less intensity, however, physio- logical cues will be less salient and psychological cues can become more relevant.

This informational processing model suggests that psychological stimuli have the potential to influence both W E and affect by occupying attention and by gener- ating feelings during exercise. Thus, situations that block out external stimuli could channel attention to internal information, making sensations associated with exercise more salient. Also, emotional cues could be processed that could generate increased or decreased affective states depending on the nature of the informa- -

tion processed. Support for attentional distractive effects during exercise has been demon-

strated by Pennebaker and Lightner (1980), who examined the effect of different attentional focus on exercising subjects by playing distracting sounds or tapes of their own breathing. In a second study, subjects either ran on an outdoor cross- country course or a lap course similar to a running track. Results of both studies indicated that factors promoting attention to the external environment reduced awareness of internal sensations.

Distraction strategies in the form of music have also been used to decrease the sensation of pain during dental procedures (Corah, Gale, Pace, & Seyrek, 1981) and electric shock (Lavine, Buchsbaum, & Poncy, 1976). As many exer- cisers appear to listen to music when exercising, it is possible that they may be utilizing the distracting and emotional qualities of music to avoid focusing atten- tion on internal feelings associated with discomfort. Conversely, screening out external distractive information through visual and auditory deprivation would presumably force exercising individuals to focus attention on internal processes, thereby increasing feelings of discomfort. The effect of distraction and depriva- tion on RPE and affective responses, however, has not been examined.

The purpose of this study therefore was to examine the effects of sensory deprivation and music on RPE and affect. It was hypothesized that subjects would report higher RPEs and lower affective responses during the deprivation condi- tion because depriving subjects of external stimuli will cause an internal focus on sensations of fatigue. In contrast, music will decrease W E and increase affect response because it will distract individuals from focusing attention on internal feedback.

Effects of Sensory Deprivation 1 169

Method

Subjects and Imtrumentation

Untrained female undergraduates (N= 24) were recruited from physical edu- cation activity classes under the guise that they would be participating in a fitness evaluation study. Biometric data are presented in Table 1.

Pe~onnance. Subjects exercised on a cycle ergometer (Monark, Model 868) calibrated before and during the study. A Franz electronic audiovisual metro- nome (Model LM-FB4) was employed to regulate subjects' pedaling revolutions per minute (60 rpm).

Physiological. A Cambridge electrocardiogram (Model VS4) was used to record HR. Electrodes were positioned at the sternum, at the fourth interspace at the right sternal margin, and to the left of the fifth thoracic vertebrae. An ECG strip was recorded for the last 10 seconds of each minute of the testing period, from which a minute rate was calculated using seven interbeat intervals.

Perception of Exertion. RPE was measured using the 15-point Borg scale (Borg, 1962), which has been found to be a valid and reliable measure of perceived exertion during exercise (Borg, 1982). Numerous studies have demonstrated the suitability of this instrument for assessing perceived effort during physical work (see Borg & Noble, 1974).

Affect. Affect was recorded using a 10-point bipolar scale developed by Rejeski (1985). For validity, see Hardy and Rejeski (1989). The scale ranged from + 5 to -5, with verbal anchors of +5 = very good, + 3 = good, + 1 = fairly good, 0 = neutral, -1 = fairly bad, -3 = bad, and -5 = very bad. Instructions for this scale were as follows:

While participating in this exercise you may experience various changes in mood (e.g., some individuals find the physiological changes that take place during exercise as pleasure while others perceive displeasure). Additionally, you may find your feelings fluctuating across time (i.e., you may jump back and forth between the two extremes at different times during exercise). Remem- ber that there are no expected changes, however, you may find that one de- velops. The important point is that you feel free to select one of the 10 points in a sequence that best represents your true feelings across the exercise.

Table 1

Biometric Data

Variables M SD

Age (Yrs) 19.20 1.53 Height (cm) 165.84 6.22 Weight (kg) 58.32 7.65 Estimated max VOp

(mllkglmin) 36.2 5.72

170 / Boutcher and Trenske

Procedures

Subjects participated in a submaximal fitness test and three separate experi- mental sessions distributed over a Cweek period. Each session lasted approxi- mately 40 minutes and every subject had a minimum of 2 days' rest between sessions. The three experimental conditions consisted of control, sensory depri- vation, and music. Subjects were asked to refrain from eating for 3 hours prior to testing, and each session was conducted at a similar time of day.

Workloads. The initial session involved completing an informed consent form as well as a personal health/exercise inventory, and undergoing a submaximal fitness test. A secondary purpose of the initial session was to acclimate subjects to the laboratory setting, instrumentation, and testing protocol. The submaximal fitness test consisted of three consecutive 6-min ergometer rides in which the work- loads were selected to produce HRs of approximately 120, 150, and 170 bpm. The working capacity was calculated by plotting IIR against the workload at the end of each trial (devries, 1980). From each subject's working capacity, loads corresponding to 60 % (light), 75 % (moderate), and 85 % (heavy) of maximal HR were determined.

Sessions. Upon arriving for the remaining three sessions, subjects were fitted with electrodes and were told that in each session they would be performing at three different work intensities which would increase in difficulty throughout the test period. Each session consisted of a 3-min warm-up at 50 watts (60 rpm), three successive 6-min trials at workloads equal to 60,75, and 85 % of predicted maximal HR, followed by a 3-min cool-down at 60 rpm. The experimenter sat behind the subject during testing. The Borg scale and the FS were positioned on a table at eye level 2 m directly in front of the cycle ergometer. RPE and affect was assessed every 1, 2.5, 4, and 5.5 minutes of each workload.

The deprived condition consisted of subjects wearing opaque goggles and cottonball earplugs. Background noise was screened out by the earplugs but sub- jects could still hear the metronome that established the cadence for pedal rate. RPE and affect responses were initiated with a tactile prompt. When receiving the prompt, subjects lifted the goggles in order to read the scales and give their response. The music condition consisted of subjects listening through earphones to their favorite music. Subjects were asked to bring a tape that they would enjoy listening to while exercising, and 21 chose music classified as lively whereas 3 chose music that was more relaxing. The control condition consisted of subjects working on the cycle ergometer without sensory deprivation or music. Order of conditions was counterbalanced. At the completion of the final session, subjects were informed of an upcoming debriefing session during which the results of the study would be discussed.

Results

Results are divided into three sections: RPE, affect, and heart rate. All analy- ses involved repeated measures for which the conservative F test correction for degrees of freedom (Geisser & Greenhouse, 1958) was applied. The Bonferroni t test procedure, which adjusts the significance level to the number of pairwise comparisons, was used to analyze cell means.

Effects of Sensory Deprivation / 171

Rating of Perceived Exertion

A 3 x 3 (condition: control, deprivation, music X work intensity: light moderate, heavy) within-subjects design was used to examine the hypotheses of interest for RPE, affect, and HR. For RPE the analysis revealed a significant main effect for condition, F(2,46)=4.77, 6 . 0 1 , and a significant main effect for load, F(2,46) = 278.21,6.01. Bonferroni t statistics were used to examine the mean comparisons at each workload. As illustrated in Table 2, RPE responses in the music condition (M=7.91) were significantly lower than responses in the deprivation condition (M=8.48) at the low load intensity, t(23)=2.91,6.01. Significant differences also existed between the control (M= 12.2 1) and deprivation conditions (M= 11.77) at the moderate load intensity, t(23) =2.53, p<.01. No significant differences existed between any of the conditions at the heavy load intensity (Table 2). Figure 1 indicates the RPE means for each workload during the three conditions. These results indicate that the only significant changes in RPE between conditions occurred between music and deprived and between control and deprived at the light and moderate workloads (Figure 1).

Table 2

Mean and Standard Errors for Rating of Perceived Exertion Responses

Control Deprived Music Workload M SE M SE M SE

Light 8.32 .27 8.48 .23a 7.91 .21a Moderate 12.21 .35a 11.77 .36a 11.74 .47 Heavy 15.35 .40 15.35 .44 14.96 .47

a = Significantly different at the 0.05 level.

Affect

For affect, the analysis revealed a significant condition-by-load interaction, F(4,92)=3.39,p<.0lY a significant main effect for load, F(2,46)=21.67,p<.01, and a significant main effect for condition, F(2,46) = 6.5 I,*. 01. No significant differences between any condition was found at the low load intensity. As shown in Table 3, however, affect responses at the moderate load intensity in the music condition (M=9.43) were significantly higher than responses in the control (M=8.95), t(23)=2.35,6.05, and deprived conditions (M=8.65), t(23)=2.98, p<.01. At the heavy load intensity, significant differences existed between the deprived (M=7.41) and music conditions (M= 8.40), t(23) = 3.37, 6 . 0 1 . No sig- nificant differences existed between any other condition at any of the three work- loads (Table 3). Figure 2 indicates the affect means for each workload during

172 1 Boutcher and Trenske

n-a Control 0-0 Deprived *-* Music

tight Moderate Heavy

LOAD

Figure 1 - RPE responses during the control, deprivation, and music conditions for low, moderate, and heavy workloads.

n-• Control 0-0 Deprived 0-* Music

10

9 b W LL

8

7

6 tight Moderate Hee y

LOAD

Figure 2 - Affect responses during the control, deprivation, and music conditions for low, moderate, and heavy workloads.

Effects of Sensory Deprivation / 173

Table 3

Means and Standard Errors for Affect Responses

Control Deprived Music Workload M SE M SE M SE

Light 9.80* .24 9.49 .28 9.87 .23 Moderate 8.95 .24a 8.65 .25b 9.43 .25a9b Heavy 7.84 .43 7.41 .40a 8.40 .35a

a= Significantly different at the .05 level; b = significantly different at the .05 level. 'Affect scores converted from the - 5 to +5 scale into a 1 to 11 scale.

Light Moderate Heavy

LOAD

Figure 3 - Heart rate responses during the control, deprivation, and music condi- tions at low, moderate, and heavy workloads.

the three conditions. These results indicate that the significant changes in affect between conditions occurred during the music, control, and deprived conditions at the moderate and heavy workloads (Figure 2).

Heart Rate Analysis on the HR data failed to produce any significant differences for

any condition among any of the workloads. These results are presented in Figure 3.

174 1 Boutcher and Trenske

Discussion

Results of this study indicate that both RPE and affect were influenced by music and deprivation. For RPE, responses were lower during music compared to deprivation for the light workload, and deprivation was higher than control during the moderate exercise workload. For affect, responses were higher (more positive) during music compared to the deprived condition at the moderate and heavy workloads. In contrast, HR did not show any change across conditions. These data suggest that both music and deprivation influenced both RPE and affect; however, RPE was affected at light and moderate workloads whereas affect was influenced at moderate and heavy workloads.

The RPE results support prior research that has demonstrated that psycho- logical variables can influence RPE (Boutcher et al., 1988; Hardy et al., 1986; Steptoe & Cox, 1988). In this study music resulted in lower RPE at the light work intensity but was similar to deprivation at both the moderate and heavy work- loads. That music only affected RPE in the light workload supports Rejeski's notion that the greatest influence of psychological factors on RPE is experienced at submaximal exercise (Rejeski & Ribisl, 1980). Thus, when exercise approaches aerobic capacity, physiological cues will tend to occupy attention and exert the greatest influence on RPE.

The influence of music on affect, in contrast to WE, occurred at the moder- ate and high work intensities. Thus subjects reported feeling better during moderate and heavy exercise when accompanied by music than when exercising in the deprived condition. The positive effects of music on RPE and affect support prior research which has demonstrated that music is effective in reducing pain during dental procedures (Jacobs & Nicastro, 1978; Silberstein, 1977). However, as the influence of music on RPE and affect was load dependent, the mechanisms under- lying these changes are unclear. For instance, as previously described, it is feasible that the effects of music on RPE were distractional in nature. Listening to music may occupy attention, thus distracting individuals and preventing them from focus- ing on feelings of discomfort. As psychological cues appear to become less salient with increases in physical work, however, this hypothesis does not explain how music can bring about significant positive changes in affect at the moderate and heavy exercise intensities.

As the Musical Mood Induction Procedure (Sutherland, Newman, & Rachman, 1982) has been successfully used to induce mood (Richards, 1981; Teasdale & Spencer, 1982), it is possible that music played during exercise may have generated positive emotional states rather than acting as a distractor. Subjects may have associated the music with positive past experiences, may have indulged in pleasant fantasizing, or may have focused attention on pleasant future events. Thus the combination of exercise-induced arousal and pleasant external stimuli may have formed the essential components of the increased affect witnessed in the music condition. Interestingly, 21 of 24 subjects chose music that was lively and uptempo in nature. Although different intensity music has been shown to differentially affect anxiety and strength performance (Pearce, 1981; Smith & Morris, 1976, 1977), future research is needed to examine the effect of lively or soothing music on affective states during exercise.

This load-dependent effect of music on RPE and affect supports the notion that RPE and affect during exercise may be separate but related phenomena (Hardy

Effects of Sensory Deprivation 1 175

& Rejeski, 1989). Thus, exercising individuals' effort sense may be similar across workloads, but how they are feeling may vary according to factors such as environ- mental conditions (e.g., music, climate, scenery) and individual differences (e.g., fitness level and training state).

Collectively, these results support an informational processing model of RPE and affect formation and imply that attentional focus and the kind of material processed perceptually will be essential determinants of RPE and affect. In the exercise setting it appears that the availability of both internal and external sources of information may differentially influence RPE and affect depending on exercise workload. If future research supports the finding that vigorous exercise and music consistently generate positive affective states, the playing of music over earphones or as background music may help people to enjoy aerobic exercise more and thus increase exercise adherence (Rejeski & Kenney, 1988).

In summary, these results suggest that psychological as well as physiological factors are important determinants of RPE and affect during exercise. In this study the effects of music on RPE and affect were load dependent. RPE was affected at light exercise levels whereas affect was influenced at more vigorous work inten- sities.

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Acknowledgment We gratefully acknowledge Lisa Rollins and Gail Nash for their help with data

collection.

Manuscript submitted: April 14, 1989 Revision received: October 4, 1989