Occupational cardiovascular disease risk profile and physical activity categories of university cleaners

ORIGINAL RESEARCH

PEER REVIEWED

 

N Rugbeer, TE Pila

 

Department of Sport, Rehabilitation and Dental Science, Tshwane University of Technology, Pretoria, South Africa
 

Correspondence: Mr Nivash Rugbeer, Private Bag X680, Pretoria, 0001. e-mail: rugbeern@tut.ac.za

 

ABSTRACT

Background: Cleaners are engaged in sustained work activities, such as standing, walking, pushing, pulling and mopping. Occupational physical activity for a prolonged period of time with inadequate levels of cardiovascular fitness increases arterial endothelial damage which contributes to cardiovascular disease.

Objectives: To determine the cardiovascular disease risk profile of university cleaners, and highlight the common risk factors associated with cardiovascular disease in this occupational group.

Methods: The study was conducted in the university’s biokinetics laboratory in Pretoria. A total of 57 university cleaners participated in the cross-sectional descriptive study. Participants were interviewed using adapted versions of the validated International Physical Activity Questionnaire and American College of Sports Medicine Risk Stratification Questionnaire. Body composition, fasting blood cholesterol and fasting blood glucose were measured in all participants at one point in time.

Results: The average age of the cleaners was 41.0 years (SD = ± 8.83). Their mean body mass index was 29.1 kg/m2 
(SD = ± 7.0). Almost a third (29.2%) of university cleaners were pre-diabetic (fasting glucose 5.6-6.9 mmol/L), and the most prevalent risk factor for cardiovascular disease was overweight (79.0%). Only 28.0% of the cleaners were engaged in moderate and high-intensity physical activity, either at work or outside of working hours.

Conclusion: Symptoms for cardiovascular disease are evident in cleaners, which suggests that an underlying chronic disease might be present. University cleaners should adhere to a supervised elevated-intensity exercise programme, individualised to their physical fitness, to reduce the risk of cardiovascular disease.

 

Keywords: chronic disease, cardiovascular symptoms, exercise intensity, cardiovascular fitness

 

INTRODUCTION

Cardiovascular disease (CVD) includes diseases such as coronary artery disease, cerebrovascular disease, congenital heart disease, heart failure and valvular heart disease, which affect the normal function of the heart and blood vessels.1 Poor cardiovascular fitness is directly related to premature mortality in the general population.2 According to the World Health Organization (WHO), the most common risk factors for CVD globally are smoking, pre-diabetes, high blood pressure, sedentary lifestyle, obesity, raised total serum cholesterol, poor diet, and excessive alcohol consumption.3 In South Africa, there is a high prevalence of CVD risk factors for atherosclerotic disease, contributing to heart disease.4 Furthermore, cardiovascular and cerebrovascular diseases, such as stroke, hypertension and ischaemic heart disease, are the leading causes of mortality in South Africa.5

Occupational physical activity tasks are activities that are task dependent, and are performed at work for a period of time. The metabolic equivalent of task (MET) is defined as the amount of oxygen consumed at rest or oxygen uptake per unit of body mass, which is equal to 3.5 ml of oxygen per kg body weight per minute.6 Classification of occupational physical activity tasks is as follows: 
< 3 METs is regarded as low activity, 3-6 METs as moderate activity, and > 6 METs as vigorous activity.7 Occupational physical activity tasks, such as walking, vacuuming and mopping, performed for 30-60 minutes, are equivalent to moderate physical activity; however, when performed throughout the day, they are regarded as physically demanding occupational tasks.8 Cleaners engage in physical occupational activity tasks, such as standing, walking, pushing, pulling, vacuuming and mopping throughout the day.9 It has been suggested that sustained occupational physical activity tasks throughout the day increase the risk of CVD in cleaners.10 The rationale for this is that sustained occupational physical activity tasks are not individualised to the cleaners’ physical capacities.11Furthermore, sustained occupational physical activity tasks require dynamic and static movement patterns for a period of 7-8 hours.8 The constant work stress reduces the cleaners’ ability to recover from occupational tasks.8 Cleaners do not adapt to sustained occupational physical activity tasks because the tasks are not individualised to their aerobic capacity, which overworks the cardiovascular system.9

Cardiovascular fitness is the ability of the heart to pump oxygenated blood to active tissue to sustain work. It has been reported that cleaners have low cardiorespiratory fitness, which generates a high relative workload during occupational physical activity tasks.9,12 Hence, low cardiorespiratory fitness contributes to the greater demand of the cardiorespiratory system to sustain occupational work.13,14 Furthermore, sustained occupational physical activity tasks, compounded by low cardiorespiratory fitness in cleaners, increases arterial endothelial damage, which contributes to CVD.15

It has been found that elevated upper extremity physical workload in cleaners is directly related to an increased risk of CVD.16 Constant upper extremity occupational tasks increase heart rate and blood pressure compared to lower extremity activities at the same absolute workload.16 With upper extremity activities, there is an increase in total peripheral resistance which results in increased workload of the myocardium.17 This contributes to excessive stress on the arterial wall, thereby increasing the risk of CVD.16,17

There is insufficient research on the CVD risk profile of university cleaners in South Africa. Furthermore, there is a paucity of literature regarding risk factors and symptoms associated with CVD risk in university cleaners. The aim of this study was to describe the CVD risk profile of university cleaners and identify common risk factors associated with CVD.

 

METHODS

A cross-sectional descriptive study was conducted among permanently employed female cleaners at a university in South Africa, who were recruited into the study using purposive sampling. Cleaning staff managers were excluded because they spend most of their time performing administrative tasks rather than occupational physical activity tasks.

 

Data collection

A pilot study was conducted amongst five cleaners at the university to minimise procedural errors and improve the reliability of the results. As language barriers were experienced during the pilot study when the questions were asked in English, the researcher explained the questions in the participants’ preferred language in the main study, to facilitate understanding.

University cleaners who met the inclusion criteria were interviewed about their general health, physical activity levels and cardiovascular disease risk profiles, using adapted versions of the validated International Physical Activity Short Form Questionnaire (IPAQ-SF) and the American College of Sport Medicine (ACSM) Risk Stratification Screening Questionnaire.

The IPAQ-SF is a self-reported questionnaire which determines levels of physical activity,18 and comprises the following domains: leisure time physical activity, domestic and gardening activities, work-related physical activity, and transport-related physical activity.19 The IPAQ-SF asks about walking, moderate-intensity activities and vigorous-intensity activities in each of these four domains. The raw scores of walking, moderate activity and vigorous activity in each domain classify persons into low intensity, moderate intensity, and high intensity activity categories, using the IPAQ core group classification model (Table 1).20 The computation of the MET scores is not specific to each domain, however.

MET scores were computed from the raw data from responses to the IPAQ-SF in the last seven days to determine physical activity categories:19 low intensity = 3.3 METs, moderate intensity = 4.0 METs and vigorous intensity = 8.0 METs.20

The ACSM Risk Stratification Screening Questionnaire was used to classify the risk for cardiovascular disease (Tables 2 and 3).21

Blood pressure was measured manually twice on the right arm, ten minutes apart, and the second reading was recorded. If blood pressure was elevated (≥ 140/90 mmHg), a referral letter was given to the participant who was encouraged to visit the medical doctor on campus, or a private general practitioner, for further evaluation and treatment.

Anthropometry measures to determine the proportions of the human body were measured according to the International Standards for Anthropometric Assessment Guidelines.22 These included the sum of skinfolds, circumference measurements, body mass index, waist to hip ratio, height and weight. Fasting blood cholesterol and random blood glucose were measured using the Accutrend GCT machine (Roche Diagnostics, Mannheim, Germany). The biokineticist and primary researcher performed all the measurements.

 

Statistical analysis

Data was analysed using the Statistical Package for Social Science Version 18.0 (SPSS) for Windows software. Descriptive analysis was performed to describe the demographic profiles and cardiovascular risks of participants. Continuous variables were summarised as means and standard deviations, and categorical variables as numbers, percentages and ranges.

Ethical clearance for this study was obtained from the Tshwane University of Technology’s Committee for Research Ethics (referral number REC/2015/06/003). The study was conducted in accordance with the Declaration of Helsinki (last update: October 2008).

 

RESULTS

A total of 57 cleaners participated in the study, aged 22-62 years (mean 41 ± 8.83 years). Mean body mass index (BMI) was 29.1 ± 7.0 kg/m2 (Table 4); 21.0% (n = 12) were normal weight (BMI 18.5-24.9 kg/m2); 28.0% (n = 16) were overweight (BMI 25-29.9 kg/m2); and 51% (n = 29) were obese (BMI ≥ 30 kg/m2). 
A high proportion had raised cholesterol (37.2%) and almost a third (29.2%) were pre-diabetic (Table 5).

The most common risk factors in the study participants were overweight (79%), dyslipidaemia (37%) and pre-diabetes (29%)  (Table 5). Many participants reported symptoms of CVD, such as pain and discomfort in the chest, neck, jaw, arms, or other areas (32%); unusual fatigue or shortness of breath with usual activities (26%); chest pains (23%); palpitations or tachycardia (19%); and fainting or dizziness (18%) (Table 6). The majority of the cleaners reported low-intensity activities (72%); few cleaners reported moderate (17.5%) or high-intensity activities (10.5%) (Table 7).

 

Table 1. Categories of physical activity intensity based on the IPAQ core group classification model 20

 

Table 2. Risk factors for CVD in university cleaners 21

 

Table 3. Classification of CVD risk in university cleaners 21

 

Table 4. Descriptive and demographic statistics of university cleaners (N = 57)

 

Table 5. Participants with risk factors for cardiovascular disease

 

Table 6. Cardiovascular disease symptoms experienced by university cleaners

 

Table 7. Cardiovascular disease risk profile and physical activity categories

 

DISCUSSION

A key finding was that the cleaners spent most of their working days performing light activities, with little time spent on moderate or vigorous activities. The long durations of light activity predispose the cleaners to chronic low-grade stress, which overloads the cardiovascular system.13,14 The occupational tasks that cleaners perform on a daily basis are not individualised to their aerobic capacities and thus inhibit adaptations to the cardiovascular system.9 Structured physical activity, quantifying intensity, frequency and duration specific to the cleaners’ physical capacities will provide a training effect.23,24 The ACSM recommends 30-60 minutes of moderate-intensity exercise five days per week, or 20-60 minutes of vigorous-intensity exercise three days per week, to reduce the risk of CVD.21

The cleaners presented with a variety of risk factors that are associated with CVD, the most common of which were overweight, dyslipidaemia and pre-diabetes. In South Africa, an estimated 65% of women and 31% of men are overweight or obese.25 A total of 24% of South Africans have elevated total cholesterol, with only 4% being aware of this.4 Furthermore, one in 10 South Africans are diagnosed with diabetes, with one in five reporting pre-diabetes.25 In 2008, the ‘Heart of Soweto Study’ postulated that there is a high prevalence of CVD risk factors in Gauteng, South Africa:4 56% of participants were diagnosed with hypertension, 44% of whom were obese.4

The cleaners also reported symptoms associated with CVD. There is a strong correlation between signs and symptoms and underlying cardiovascular or cerebrovascular disease.21 Therefore, to reduce the risk of an acute cardiovascular incident, university cleaners should be medically screened on a regular basis for cardiovascular disease, to facilitate early detection of CVD.

Cleaners are exposed to a limited degree of moderate and vigorous occupational physical activity tasks. Sustained occupational physical activity tasks stress the cardiovascular system.10 Furthermore, sustained occupational physical activity tasks that are not individualised to cleaner’s relative aerobic capacity, increase arterial endothelial damage, which contributes to CVD.15 Therefore, university cleaners should engage in individualised and supervised structured moderate and high-intensity exercise programmes, relevant to their aerobic capacity. This will improve cardiovascular fitness and reduce the workload of the heart, which will concomitantly reduce the risk of CVD.

 

Limitations

Physical activity was reported using the IPAQ Questionnaire and not measured objectively. Future studies should measure physical activity objectively using accelerometers. Furthermore, non-communicable diseases, such as hypertension, diabetes, chronic lung disease, asthma and cancer should be investigated in university cleaners with a larger sample size.

 

CONCLUSION

University cleaners should engage in moderate and high-intensity physical activity quantifying intensity, frequency and duration specific to their physical capacities, which will provide adaptations to the cardiovascular system and reduce the risk of CVD. Additionally, to reduce the risk of an acute cardiovascular incident, university cleaners should be regularly screened for CVD.

 

LESSONS LEARNED

1. Cleaners spend little time performing moderate and high intensity physical activities and are at risk of CVD.

2.  In order to reduce the CVD risk, university cleaners should engage in exercise programmes after screening by biokineticists to customise and individualise their exercise according to cardiorespiratory fitness.

 

ACKNOWLEDGEMENTS

A kind word of thanks goes to Gladys Mahlangu, the senior manager of the cleaners, for her interest in the study. The authors express their gratitude to the university and cleaners who participated in the study.

 

DECLARATION

The authors declare that they have no financial or personal relation-ship(s) that may have inappropriately influenced them in writing this paper.

 

REFERENCES

1. Mozaffarian D, Benjamin EJ, Go AS, Arnett DK, Blaha MJ, Cushman M, et al. Heart disease and stroke statistics – 2015 update: a report from the American Heart Association. Circulation. 2015; 131(4):e29-322.

2. Lee D-c, Artero EG, Sui X, Blair SN. Mortality trends in the general population: the importance of cardiorespiratory fitness. J Psychopharmacol 
(Oxford, England). 2010; 24(4_supplement):27-35.

3. World Health Organisation. Cardiovascular diseases (CVDs): Fact sheet No. 317 [Internet]. 2011. Available from: http://www.who.int/mediacentre/factsheets/fs317/en/ (accessed 12 Feb 2018).

4. Sliwa K, Wilkinson D, Hansen C, Ntyintyane L, Tibazarwa K, Becker A, et al. Spectrum of heart disease and risk factors in a black urban population in South Africa (the Heart of Soweto Study): a cohort study. Lancet. 2008; 371(9616):915-922.

5. Pillay-van Wyk V, Dorrington R, Bradshaw D. Rapidly changing mortality profiles in South Africa in its nine provinces. S Afr Med J. 2017; 107(3):168-169.

6. Jette M, Sidney K, Blumchen G. Metabolic equivalents (METs) in exercise testing, exercise prescription, and evaluation of functional capacity. Clin Cardiol. 1990; 13(8):555-565.

7. Hills AP, Mokhtar N, Byrne NM. Assessment of physical activity and energy expenditure: an overview of objective measures. Frontiers in nutrition. 2014; 1:5.

8. Sjøgaard G, Christensen JR, Justesen JB, Murray M, Dalager T, Fredslund GH, et al. Exercise is more than medicine: the working age population’s well-being and productivity. J Sport Health Sci. 2016; 5(2):159-165.

9. Korshoj M, Krustrup P, Jespersen T, Sogaard K, Skotte JH, Holtermann A. A 24-h assessment of physical activity and cardio-respiratory fitness among female hospital cleaners: a pilot study. Ergonomics. 2013; 56(6):935-493.

10. Li J, Loerbroks A, Angerer P. Physical activity and risk of cardiovascular disease: what does the new epidemiological evidence show? Curr opin cardiol. 2013; 28(5):575-583.

11. Søgaard K, Sjøgaard G. Physical activity as cause and cure of muscular pain: evidence of underlying mechanisms. Exerc sport sci rev. 2017; 45(3):136-145.

12. Korshoj M, Lidegaard M, Skotte JH, Krustrup P, Krause N, Sogaard K, et al. Does aerobic exercise improve or impair cardiorespiratory fitness and health among cleaners? A cluster randomized controlled trial. Scand J Work Environ Health. 2015; 41(2):140-152.

13. Clays E, Lidegaard M, De Bacquer D, Van Herck K, De Backer G, Kittel F, et al. The combined relationship of occupational and leisure-time physical activity with all-cause mortality among men, accounting for physical fitness. Am J Epidemiol. 2013; 179(5):559-566.

14. Holtermann A, Burr H, Hansen JV, Krause N, Søgaard K, Mortensen OS. Occupational physical activity and mortality among Danish workers. Int Arch Occup Environ Health. 2012; 85(3):305-310.

15. Krause N, Brand RJ, Arah OA, Kauhanen J. Occupational physical activity and 20-year incidence of acute myocardial infarction: results from the Kuopio Ischemic Heart Disease Risk Factor Study. Scand J Work Environ Health. 2015; 41(2):124-139.

16. Korshøj M, Krustrup P, Jørgensen MB, Prescott E, Hansen ÅM, Kristiansen J, et al. Cardiorespiratory fitness, cardiovascular workload and risk factors among cleaners; a cluster randomized worksite intervention. BMC Public Health. 2012; 12(1):645.

17. Mayet J, Hughes A. Cardiac and vascular pathophysiology in hypertension. Heart. 2003; 89(9):1104-1109.

18. Bassett DR, Jr. International physical activity questionnaire: 12-country reliability and validity. Med Sci Sports Exerc. 2003; 35(8):1396.

19. Malambo P, Kengne AP, Lambert EV, De Villiers A, Puoane T. Prevalence and socio-demographic correlates of physical activity levels among South African adults in Cape Town and Mount Frere communities in 2008-2009. Arch Public Health. 2016; 74:54.

20. IPAQ Group. Guidelines for Data Processing and Analysis of the International Physical Activity Questionnaire (IPAQ) – Short and Long Forms. IPAQ Group, 2005.

21. ACSM’s Guidelines for Exercise Testing and Prescription-8th ed. Philadelphia: Lippincott Williams & Wilkins; 2010. p. 23-37.

22. Marfell-Jones TOASLCM, Stewart A, Marfell-Jones M. International standards for anthropometric assessment. International Society for the Advancement of Kinanthropometry; 2006.

23. Rivilis I, Van Eerd D, Cullen K, Cole DC, Irvin E, Tyson J, et al. Effectiveness of participatory ergonomic interventions on health outcomes: a systematic review. Appl Ergon. 2008; 39(3):342-358.

24. Holtermann A, Jørgensen MB, Gram B, Christensen JR, Faber A, Overgaard K, et al. Worksite interventions for preventing physical deterioration among employees in job-groups with high physical work demands: background, design and conceptual model of FINALE. BMC Public Health. 2010; 10:120.

25. Shisana O, Labadarios D, Rehle T, Simbayi L, Zuma K, Dhansay A, et al. South African National Health and Nutrition Examination Survey (SANHANES-1). Cape Town: Health Sciences Research Council; 2013.

Download this Article

Login

Email address
Password
Forgot password?

 

  Login