Public Health Nutrition: 4(5A), 1107-1116 DOI: 10.1079/PHN2001192

Physical activity patterns in a nationally representative sampleof adults in Ireland

MBE Livingstone1'* PJ Robson1, S McCarthy2, M Kiely3, K Harrington2, P Browne1,M Galvii/, NJ Wareham4 and KL Rennie4

Irish Universities Nutrition Alliance (IUNA) at: Northern Ireland Centre for Diet and Health (NICHE),University of Ulster, Coleraine, Co. Londonderry, BT52 ISA, Northern Ireland: department of Clinical Medicine,Trinity Centre for Health Sciences, St James's Hospital, Dublin 8, Republic of Ireland: 3Nutrition Sciences,Department of Food Science and Technology, University College, Cork, Republic of Ireland:institute of Public Health, University of Cambridge, Cambridge, CB2 2SR, UK

AbstractObjective: To evaluate habitual levels of physical activity in a nationallyrepresentative sample of adults in Ireland.Design: Cross-sectional survey using a self-administered questionnaire. Usual levelsof work, recreational and household activities were evaluated in relation toanthropometric, demographic and socio-economic characteristics. The amount andintensity of all activities were quantified by assigning metabolic equivalents (METS)to each activity.Setting: Republic of Ireland and Northern Ireland, 1997-1999.Subjects: Random sample of 1379 adults aged 18-64 years.Results: Men were approximately twice as active in work and recreational activity(139.7 ± 83-9 METS) as women (68.5 ± 49-8 METS; P < 0.001), but women werethree times more active in household tasks (65-9 ± 58.7 METS vs. 22.6 ± 24.6 METS;P < 0.001). Overall levels of physical activity declined with increasing age,particularly leisure activity in men. In women the decline in work activity wasoffset by spending more time in household pursuits. Twenty-five per cent of thesubjects were extremely overweight (body mass index (BMI) > 28kgm~2) or obese(BMI > 30kgm~2). Fewer obese subjects reported higher levels of work and leisureactivities. However, a higher percentage of obese women reported participation inthe higher levels of household activities. Participation rates in recreational activitieswere low. Walking was the most important leisure activity of both men (41%) andwomen (60%). In terms of hours per week spent in vigorous physical activity, menwere more active than women, professional and skilled non-manual women weremore active than women in other social classes, and younger subjects (aged 18-35years) were more active than older subjects.Conclusions: The holistic approach used in the assessment of physical activity in thisstudy has revealed important and subtle differences in the activity patterns of menand women. Failure to fully characterise the respective activity patterns of men andwomen could lead to ill-informed public health policy aimed at promoting andsustaining lifetime habits of physical activity. The results suggest that simplepopulation-focused programmes to promote physical activity are unlikely to offerthe same chance of long-term success as more sensitive and individualised strategies.

KeywordsPhysical activity patterns

OverweightObesityIreland

Social dossCross-sectional survey

During the course of the last century, changes in lifestylehave had a profound impact on patterns of energyexpenditure and physical activity in affluent countries.Increased mechanisation in the workplace has markedlyreduced the need for moderate and high intensity activity.In the home, the energy cost of housework has also beenminimised while television viewing and related pursuitsnow monopolise much of the available leisure time of a

significant proportion of the population. As a result,predominantly sedentary populations can survive withminimal exertion and can achieve energy equilibrium at alevel of energy expenditure below that consideredoptimal for health.

Epidemiological evidence has demonstrated thatphysically inactive adults are at increased risk of variouschronic diseases including coronary heart disease1"7,

* Corresponding author: Email mbe.livingstone@ulst.ac.uk © The Authors 2001

1108 MBE Livingstone et al.

hypertension8'9, non-insulin-dependent diabetes melli-tus10'11, osteoporosis12"14, various cancers15"17, anxietyand depression18 as well as all-cause mortality19"22. Theinfluence of an inactive lifestyle on weight regulation ismore complex, since the relative contributions made byovereating and inactivity in long-term positive energybalance are unclear. While there is little doubt that asedentary lifestyle is implicated in the aetiology ofobesity, there is a paucity of longitudinal data examiningthe role of physical activity in body weight control.Indices of a sedentary lifestyle, such as the number of carsper household or hours watching TV per week, provideonly indirect evidence of a causal relationship23. Never-theless, participation in physical activity is one of the bestpredictors of success in long-term maintenance of weightreduction24"26, and for attenuating weight gain over timein healthy adults27"29.

It appears that physical activity does not have to bevigorous in order to produce health benefits. Recentreports30'31 emphasise that substantial health benefits canresult by accumulating 30 minutes or more of moderate-intensity activity on most - and preferably all - days ofthe week. Moreover, because the total amount of activityis more important than its form, intensity or duration, thebenefits can be accrued by participating in a variety ofstructured and unstructured activities. However, while thebenefits of regular physical activity are well-documentedand exercise is now included in most health promotionrecommendations, it is clear that while activity levels arevariable, overall, only a minority of adults in the USA32'33

and Europe34"38 are sufficiently active for health. Thelowest levels of inactivity are observed in women32"35'38,older adults32"35'38 and those with a lower level ofeducation32"35'38"40.

To date there has been no comprehensive analysis ofthe usual levels of physical activity in a nationallyrepresentative sample of the Irish population. Conse-quently the aim of the present study was to evaluatetheir habitual levels of physical activity in self-reportedoccupational, recreational and household pursuits inrelation to anthropometric, demographic and socio-economic characteristics.

Methods

The assessment of habitual levels of physical activity of arandom sample of 1379 Irish adults aged 18-64 years wascarried out as part of the North/South Ireland FoodConsumption Survey (NSIFCS). In brief, the primary aimof the survey was to establish a database of the habitualfood and drink consumption of a representative sampleof Irish adults. Supplementary information was alsocollected on anthropometry, employment status, socio-demographic variables, lifestyle factors, smoking habits,alcohol consumption, usual levels of physical activity,health status and attitudes, medication and supplement

use. The methods used in the survey, including recruit-ment procedures, are described in detail elsewhere 1. Themain phase of the fieldwork started in October 1997 anddata collection was completed in October 1999.

Body weight in light indoor clothing and without shoeswas measured to the nearest 0.1 kg (Seca Alpha model707; Seca, Hamburg, Germany) and height to the lastcompleted 0.1 cm using a free-standing portable stadio-meter. The body mass index (BMI) of each subject wascalculated as weight in kilograms divided by the squaredheight in metres (kg m~2). According to the criteria of theInternational Obesity Task Force42, overweight or pre-obesity was defined as a BMI between 25 and29.99 kg m~2 and obesity as BMI > 30kgm"2. No furthersubdivision by grade of obesity (1, 2 or 3) was made inthis analysis.

The division of the sample into social class groups wasbased on the respondents' occupation (including lastmain occupation for those not working or retired) or, ifthe respondent was not the head, the head of household'soccupation. All subjects were classified according to theUK Standard Occupational Classification of the Office ofPopulation Censuses and Surveys (OPCS)43 and theCentral Statistics Office, Census % Occupations of theRepublic of Ireland44. However, because of the broadsimilarity between the two systems of classification andfor simplicity and consistency with other surveys, theOPCS system was adopted for all subjects in this study. Inaddition, the OPCS social class categories have beenreduced to four categories (professional, managerial andtechnical; skilled non-manual; skilled manual; partlyskilled and unskilled) in order to provide large enoughsamples to examine the results separately for men andwomen from different age groups.

Levels of customary physical activity were assessed by aself-administered questionnaire that was developed at theInstitute of Public Health, University of Cambridge. Thequestionnaire consisted of three sections: activity athome, work and recreation. Information on physicalactivity was collected in the context in which it wasundertaken, and in such a way that the data could beanalysed according to the dimension of physical activityof interest. In each case, questions were closed ratherthan open-ended, to make them easy to complete and tofacilitate large-scale data entry. Under household pursuits,the amount of time spent on TV viewing and relatedactivities, stair climbing, shopping, cooking, cleaning andcare-giving were queried in detail. Questions on occupa-tional activity were derived from the Modified TecumsehOccupational Activity Questionnaire, which has beenvalidated elsewhere45'46. Subjects were questioned on themode of travel to and from work, and the duration ofwork of varying intensities while sitting, standing andwalking. In addition, subjects were asked about fre-quency of stair climbing, kneeling and squatting. Theleisure time section was based on the validated Minnesota

Physical activity patterns in Ireland 1109

Leisure Time Activity Questionnaire47'48 with activitiesordered according to the frequency in a UK population34.Respondents were asked to identify the frequency andduration of their participation in 36 named recreationalpursuits, including sports and gardening activities. Foreach activity, respondents indicated the number of timesthey performed the activity in the past year and theaverage duration per episode. For activities that couldinvolve varying levels of intensity such as walking andgardening, subjects were also asked to indicate the levelof intensity of such activities. An additional open-endedquestion assessed information on recreational physicalactivities not specified in the questionnaire.

The intensity of all self-reported physical activity inwork, household and recreational activities wasexpressed as an activity metabolic equivalent (MET)index by assigning a multiple of resting metabolic rate(MET score) to each activity. One MET score is equivalentto the energy expenditure during seated rest, approxi-mately 35 ml of oxygen consumed per kilogram of bodyweight per minute. Metabolic equivalents thereforerepresent the ratio of work metabolic rate to restingmetabolic rate and are independent of body weight49.Metabolic equivalent levels were obtained for eachactivity from the compendium of physical activitiesdeveloped by Ainsworth et al.49. The time spent in eachactivity was multiplied by the appropriate MET score andsubsequently summed over all activities to give an overallestimate of MET hours per week (referred to as METS inthis study). METS therefore represent both the amountand relative intensity of physical activity during the weekfor each subject.

The overall weekly MET hours for leisure time (Leisure-METS), work (Work-METS) and household (Home-METS)activity were computed. Total-METS were calculated bysumming Leisure-METS and Work-METS. Additionally, thetime spent on various recreational activities, includingvigorous activities (any activity of 5.0 MET or more) andTV viewing and related pursuits was also reported.

Statistical analysisStatistical analysis was carried out using SPSS forWindows version 9.0.1 (SPSS Inc., Chicago, IL). Physical

characteristics and time spent in various activities weresummarised using mean ± standard deviation (SD),whereas the distributions of MET values were describedusing 25th, 50th and 75th percentiles. Differencesbetween the mean values were assessed using indepen-dent samples Mests or one-way analysis of variance(ANOVA), and Mann-Whitney f/-tests were used to assessdifferences in median values obtained for METS derivedfor males and females. P-values less than 0.05 wereconsidered to be statistically significant.

Results

Sample descriptionThe physical characteristics of the subjects are presentedin Table 1. As a group, men were significantly taller,heavier and fatter than women (all P < 0.001), but in bothgroups average BMI increased with increasing age. Withthe exception of the youngest women, the mean BMI ofall groups was in the overweight category. The 75thpercentile of BMI was 29.2 and 28.1 kg m~2 for men andwomen, respectively, indicating that approximately 25%of each group was extremely overweight or obese.

Men vs. womenMen were significantly more active overall than women,and in different ways. When comparing mean (±SD)levels of activity, men were approximately twice as activein work and recreational activity (139-7 ± 83-9 METS) aswomen (68.5 ± 49-8 METS), but women were three timesmore active in household tasks (65.9 ± 58.7 METS vs.22.6 ± 24.6 METS). Time spent on TV viewing and relatedpursuits was similar for men (19 ± 10 h week"1) andwomen (18 ± 10 h week"1). Twenty-five per cent of thesubjects spent 25 h week"1 in these pursuits.

Of the 12 recreational activities in which subjectsparticipated at least once a week, walking for pleasurewas by far the most important for both men (41%) andwomen (60%), followed by gardening and floor exercises(Table 2). Thereafter, gender differences emerged in thetype of leisure-time activities undertaken but, overall,men spent significantly more time in vigorously active

Table 1 Description of the subjects

Males

Females

Age group

18-35.9 years36-50.9 years51 -64.9 yearsTotal18-35.9 years36-50.9 years51-64.9 yearsTotal

n

240217156613265281152698

Height (m)

Mean

1.771.751.731.75*1.631.621.601.62

SD

0.070.060.070.070.060.060.060.06

n

249235171655269285160714

Weight (kg)

Mean

81.084.883.282.9*64.668.271.067.5

SD

13.313.613.613.311.612.313.312.5

n

240217156613265281152698

BMI (kg rrT2)

Mean

25.827.727.626.9*24.426.127.825.8

SD

3.64.33.64.04.34.45.54.8

* Significantly different from females, P < 0.001 (independent samples Mest).

1110 MBE Livingstone et al.

Table 2 Leisure-time activitiest - percentages of subjects participating in each activity once a week or more

Males (n = 648)

Activity

Walking for pleasureMowing the lawnDIYFloor exercisesFootball/rugby/hockeyWatering the gardenDigging, shovelling, or chopping woodWeeding, pruningJoggingSnooker/billiards/dartsExercises with weightsGolf

% of males participatingonce a week or more

41.128.517.315.315.214.714.312.010.19.89.79.2

Females

Activity

Walking for pleasureWatering the gardenFloor exercisesWeeding, pruningMowing the lawnConditioning exercisesDancingGeneral swimmingExercises with weightsMusical instrument playingStep/high impact aerobicsCompetitive/lap swimming

(n = 705)

% of females participatingonce a week or more

60.320.119.115.114.811.810.77.95.75.75.44.9

t Twelve most frequently undertaken activities, listed for each sex.

recreational pursuits than women (1.7 ± 2.7 h week !

men vs. 1.0 ± U h w e e k " 1 women, P < 0.001; Fig. 1).

AgeThe overall trend was for a decline in all types of physicalactivity with increasing age (Table 3). Compared with theyoungest age group, median Total-METS derived for theoldest subjects decreased by approximately 25% in menand 50% in women. However, gender differences in thepattern of this decline were apparent. While the work andhousehold activity levels of men were maintained untilage 51 years, the decline in leisure-time activity wasevident at a younger age. Consequently, in the oldest agegroup, median METS declined by 20-30% in work andhousehold activity but by 50% in leisure-time pursuits. In

contrast, while women spent significantly less time inleisure-time activities at all ages compared with men,nevertheless they sustained these levels across the ages.In the oldest age group, half of the women undertook nowork-related activity, but compensated by spending moretime in household pursuits.

There were no age-related trends in the amountof time spent watching TV, but with increasing age,the time spent in vigorous leisure-time activitydeclined significantly in both men and women (Fig. 1).Thus, the amount of time spent in vigorous physicalactivity by the youngest men (2.72 ± 3.28 h week"1)and women (1.44 ± 2.02 h week"1) had declined to0.60 ± 1.6 h week"1 and 0.40 ± 0.94 h week"1 in theoldest men and women, respectively (P < 0.05;

Males D Females

18.0-35.99 years 36.0-50.99 years

Age categories

c,f

51.0-64.99 years

Fig. 1 Hours per week spent in vigorous physical activity by subjects in each age group. Values are mean and standard error of mean(SEM). For each sex, differences between BMI categories assessed using ANOVA with LSD. Within each BMI category, differencesbetween sexes assessed using independent samples f-tests. Values with different superscripts are significantly different at P < 0.05

Physical activity patterns in Ireland 1111

Table 3 Energy expenditure estimates (METS) for total, work, leisure and home activities, for different age categories

Males (n = 648)18-35.9 years36-50.9 years51 -64.9 yearsTotal

Females (n = 705)18-35.9 years36-50.9 years51 -64.9 yearsTotal

Total

25th

90.193.860.287.8

45.529.114.129.0

(percentiles)

50th

135.5140.5104.3127.4

80.061.538.664.8*

75th

200.7195.6152.6186.6

104.486.481.594.3

METSf

Work (percentiles)

25th

60.965.428.759.3

27.30.70.00.0

50th

92.7102.470.591.8

60.043.8

0.049.0*

75th

152.5132.9133.7147.0

78.871.663.974.1

Leisure

25th

15.89.19.2

10.5

7.46.75.46.7

(percentiles)

50th

30.621.216.423.7

15.713.014.514.2*

75th

52.738.637.444.3

28.225.227.626.8

Home

25th

6.76.63.05.4

20.344.039.833.3

(percentiles)

50th

14.815.410.413.9

42.468.761.058.8*

75th

30.535.324.729.4

88.394.086.490.3

f Multiples of resting metabolic rate x hours per week.* Significantly different from males, P < 0.001 (Mann-Whitney West).

ANOVA with least significant difference (LSD)). Fiftyper cent of the latter group reported no vigorousrecreational physical activity.

BMIThe mean values for BMI and the prevalence of over-weight and obesity in men and women for each of thequartiles of Total-, Work-, Leisure- and Home-METS arepresented in Table 4. Higher levels of total work andrecreation activities were associated with a trend towardslower BMI, in both men and women. For home-relatedactivities, however, this trend was reversed in women andwas no longer apparent in men. No clear pattern emergedin the activity levels of overweight subjects, with theexception of work activity of women. Fewer overweight

women were involved at higher levels of work activity,and this in turn largely accounted for the overall trendtowards a decline in total activity levels with increasingfatness. An inverse relationship was observed with regardto the percentage of obese subjects who engaged inincreasing levels of total, work and leisure activity. Again,the notable exception was home-related activity wherethe pattern was inconsistent in men, but where a higherpercentage of obese women participated in the higherlevels of household activities.

Lean men engaged in vigorously active recreation for1.9 — 2.6 h week"1 but this was not significantly differentfrom overweight (1.6 ± 2.7 h week"1) and obese (1.3 ±3.0 h week"1) men (Fig. 2). However, overweight (0.8 ±l^hweek"1) and obese women (0.7 ± 1.5hweek"1)

Table 4 Distribution of BMI and prevalence of overweight and obesity among male and female subjects by quartiles of total physical activity(Total-METS), work physical activity (Work-METS), leisure-time physical activity (Leisure-METS) and household physical activity (Home-METS)

Total-METS1st quartile2nd quartile3rd quartile4th quartile

Work-METS1st quartile2nd quartile3rd quartile4th quartile

Leisure-METS1st quartile2nd quartile3rd quartile4th quartile

Home-METS1 st quartile2nd quartile3rd quartile4th quartile

Males

Mean

27.726.527.026.6

27.426.626.926.9

27.627.126.826.3

27.226.526.927.1

BMI

SD

4.43.64.23.6

4.33.84.03.8

4.44.13.73.6

3.94.13.94.0

(kg rrT2)

Females

Mean

26.725.925.225.5

27.125.325.425.4

26.226.025.525.7

25.225.826.026.3

SD

5.44.64.54.5

5.24.54.64.6

5.15.14.64.3

5.04.25.04.9

Percentage overweight(BMI = 25-29.9 kg m~2)

Males

41.445.744.442.0

38.946.344.244.1

40.750.040.742.0

45.545.937.444.7

Females

38.132.830.525.7

42.226.630.926.7

30.630.033.932.4

29.533.332.431.8

Percentaae obese(BMI > :

Males

26.515.418.514.2

26.514.818.414.9

23.519.117.314.8

18.815.721.518.6

30 kg m"2)

Females

18.215.812.415.4

20.013.013.115.3

17.916.712.414.8

10.814.717.618.8

1112 MBE Livingstone et al.

Males a Females

<25 kg m~2 25-29.99 kg rrT

BMI category

>30 kg m"

Fig. 2 Hours per week spent in vigorous physical activity by lean, overweight and obese subjects. Values are mean and standard error ofmean (SEM). For each sex, differences between BMI categories assessed using ANOVA with LSD. Within each BMI category, differencesbetween sexes assessed using independent samples f-tests. Values with different superscripts are significantly different at P < 0.05

spent significantly less time in these pursuits than leanwomen (1.2 ± 0.7 h week"1; P < 0.05). On average, theoverweight and obese spent 2-3 hours per week more inTV viewing than non-overweight subjects. For men, thesedifferences were not significant. However, obese womenwatched significantly more TV than lean women (20.2 ±l l ^hweek" 1 vs. 17.2 ± 10.4hweek-1; P < 0.05).

Social classThe impact of social class grouping on activity patternswas less consistent than that of gender, age and BMI. Theresults in Table 5 demonstrate a trend for professional andskilled non-manual men to engage in less total and work-related activity than men from other social groups but thetrend was reversed in the women. Involvement inhousehold activities by men was broadly similar acrosssocial class groupings but women in skilled manual,

partly skilled and unskilled occupations spent more timein these activities than women from other social groups.

The time spent in vigorously active recreation by menranged from 1.2 ± 2.4 h week"1 (skilled manual) to 2.0 ±3-4 h week"1 (skilled non-manual) but none of thesedifferences were significant. On the other hand, there wasan approximately two-fold difference in the range oftime spent in vigorously active recreation by the women(0.7 ± O^hweek"1 skilled manual vs. 1.2 ± 2-Ohweek"1

skilled non-manual). Women in professional and skillednon-manual groups spent significantly more time in thesepursuits than women in other social class groupings(P < 0.05). Clear social class differences were observedin TV viewing habits. The amount of time spent in thisactivity by professional men (17.3 ± 9.6 h week"1) andwomen (16.0 ± 8.9 h week"1) was significantly lessthan that by men (20.8 ± 9-9 h week"1) and women

Table 5 Energy expenditure estimates (METS) by social class for total, work, leisure and home activity

MalesProfessional, managerial

& technicalNon-manual skilledManual skilledPartly skilled & unskilledTotal

FemalesProfessional, managerial

& technicalNon-manual skilledManual skilledPartly skilled & unskilledTotal

n

276

75160134645

302

156104139701

%

42.8

11.624.820.8

100

43.1

22.314.819.8

100

Total

25th

81.8

69.1110.368.982.6

44.5

39.410.516.429.8

(percentiles)

50th

116.4

101.5157.9141.8127.3

71.4

69.132.842.565.7

75th

162.9

160.8205.2196.2187.0

97.2

96.575.890.094.5

METSf

Work (percentiles)

25th

59.5

51.284.627.159.3

20.0

17.50.00.00.0

50th

81.7

70.3131.195.791.6

58.2

52.30.0

24.249.1

75th

132.7

119.0176.8143.3147.0

78.7

71.062.171.874.2

Leisure (percentiles)

25th

9.6

13.99.5

11.010.5

8.5

7.55.54.56.8

50th

22.4

22.023.430.323.7

14.8

15.311.713.014.3

75th

38.5

41.549.052.544.2

25.9

30.025.727.627.0

Home

25th

5.8

8.64.26.35.4

33.2

26.656.332.533.2

(percentiles)

50th

16.8

14.49.7

15.713.8

58.5

45.475.864.058.8

75th

33.0

27.426.929.929.4

88.5

78.3118.098.690.7

t Multiples of resting metabolic rate x hours per week.

Physical activity patterns in Ireland 1113

(21.1 ± 12.5 hweek l) who were classified in otheroccupations.

Discussion

In the present study, the usual patterns of physical activityin a representative sample of the Irish adult populationwere characterised using a comprehensive physicalactivity questionnaire. The physical activity questionnaireremains one of the most feasible and cost-effectivemethods for assessing physical activity in the epidemio-logical context. However, "comparisons between studiesare bedevilled by measurement error associated with self-reported activities, use of a diversity of definitions ofphysical activity, differences in the time frame of studiesand undue focus in many studies on a relatively narrowrange of activities50"53. In particular, the overwhelmingimportance attached to the role of sport and otherrecreations, to the exclusion of household activities, ishighly likely to have biased many assessments of non-occupational physical activity. As a result, estimates ofphysical activity by many of the questionnaires used inearlier studies have been shown to relate more closely tophysical fitness than habitual activity54.

A major strength of the present study is that it providesa detailed assessment of all areas of an individual's dailyphysical activity (occupational, sports and other recrea-tions and non-sporting, non-occupational activity) and istherefore more likely to appropriately characterise activitylevels. With the caveat that direct comparisons betweenstudies is difficult, the present results are broadlyconsistent with those of previous epidemiological studiesof physical activity, namely that men are more active thanwomen and activity levels decline with increasing ageand are inversely associated with adiposity in bothsexes32"35-38.

One of the most significant findings of this survey isthe distinction between the physical activity patterns ofmen and women. Overall, men are twice as active inoccupational and leisure-time activities, while women arethree times more active in household pursuits. It isconceivable, therefore, that the disparity between thephysical activity levels of men and women that has beenobserved in previous studies which omitted assessmentsof household activities may be more apparent than real,simply because the questionnaires used have bettercharacterised the physical activity levels of men55"57.More all-inclusive studies of physical activity demonstratethat it is not unusual for women to spend at least 2 hoursper day in household and family care tasks, comparedwith about 30 minutes for men58. An additional explana-tion for why the assessment of physical activity may havebeen more accurate in men than women is that recall andmeasurement error tend to be greater for light andmoderate-intensity activity compared with vigorousactivity, which tends to be more time delineated58'59.

Consequently, if women perform activities that aremostly of lower intensity, errors in the estimation oftheir physical activity patterns could be magnified. Giventhe potential significance of household activities to theoverall energy expenditure of women, it could bespeculated that the proportion of women who meetcurrent activity recommendations is probably greaterthan generally perceived55. It may also offer a possibleexplanation for the observations that, in contrast tomen, physical activity in women is poorly associatedwith reduced risk of mortality5 \

Unfortunately, the downward shift in the occupationalactivity levels of the men with increasing age is notcompensated for by increased leisure or householdactivities. Indeed, leisure-time activity declines at aneven greater rate. On the other hand, the activity levelsof women are more likely to be sustained over time,through substitution of reduced or no occupationalactivity with increased levels of activity in householdpursuits. While the contribution of work-related activity tototal activity should not be underestimated, it is arguablyof less interest than non-occupational activity, since it isnot normally subject to increases through health promo-tion efforts. Although it is notoriously difficult to measureaccurately, all indications are that work-related activity,even in manual occupations, has declined substantiallyover recent decades, and will probably continue to do so.Data from Finland suggest that the energy demands ofwork activity have declined by 225 kj day"1 between1982 and 199262. Thus the nature, intensity and durationof non-occupational physical activity are likely to assumeeven greater significance in dictating the overall pattern ofenergy expenditure in the future. Nevertheless, just asincreased reliance on technology has substantiallyreduced the energy demands of work activity, so toohas it reduced the energy demands of household activity.However, as this study has clearly demonstrated, the lattermay be an invaluable adjunct to overall energy expendi-ture in the face of the declining demands of work activity.

At the same time, realistically achievable inputs ofdiscretionary physical activity in sports and other recrea-tions can have a significant impact in counteracting lowlevels of work and/or household activities 3. In thissubject group, sport and other recreational activitiesaccounted for about 25% and 20% of the estimatedoverall total MET hours spent in physical activity of themen and women, respectively. In common with earlierstudies32'34'38, walking for pleasure and gardening werethe most frequently selected recreational activities whilethere was only minimal participation in vigorously activesports. Although TV viewing and related pursuits wereconsidered separately from other leisure-time activities inthis survey, it is clear that TV viewing monopolised amajor portion of available leisure time.

A possible explanation for the observed decline withincreasing age in leisure-time activity by the men might be

1114 MBE Livingstone et al.

a shift in the type of recreational activities engaged in. Theamount of time spent in vigorous recreational activitydecreased by 50% in each of the two older age groups,suggesting that participation in higher intensity recrea-tional activities and team sports at a younger age issubsequently displaced in favour of less physicallydemanding recreations. Moreover, less time is spent inthese activities. On the other hand, the stability with ageof leisure-time activities in women, together with a lesspronounced decline in vigorous activities (albeit fromlower levels in the first place), suggest that they may haveadopted more lifetime and individualised leisure pursuitsfrom the outset, and have been able to sustain these overtime. Thus, the higher rates of participation in walking bywomen suggest that greater focus should be placed onincreasing activity levels by promoting those activities thatcan easily be incorporated and sustained within existinglifestyles. Since the health benefits of physical activityare linked principally to the total amount of energyexpended2'4'19'29'30, the outcomes of this study endorsethose of earlier studies and support the need toincrease the moderate-intensity leisure-time activity ofthe population in general, but particularly in those whoare employed in sedentary occupations and whoseinvolvement in household tasks is minimal.

The lack of a consistent association between socialclass and physical activity levels is somewhat at variancewith the observation in many studies that levels ofphysical activity are directly correlated with level ofeducational attainment32"35'38"40. There are a numberof possible reasons for this. Firstly, educational status maynot be an appropriate proxy measure for social groupingand vice versa. Secondly, since many surveys of physicalactivity focus on leisure-time activity and do notadequately address occupational and non-sporting, non-occupational activity, there is likely to have been somemisclassification of lower income or less educatedsubjects who have physically demanding jobs. However,to the extent that TV viewing is an indirect marker of asedentary lifestyle, the results of this study do indicatehigher levels of leisure-time inactivity by subjects in partlyskilled and unskilled occupations. Thirdly, the data maysimply reinforce the fact that most occupations, even inthe manual category, are becoming increasingly seden-tary. Finally, the over-representation of subjects from theprofessional and managerial social group may haveresulted in unrepresentative physical activity profiles. Itcould be argued that if social class and educational statusare proxy measures of a cluster of factors (knowledge,time, social support, access to facilities, neighbourhoodsafety) known to impact on physical activity levels, it maybe more instructive to directly assess the impact of thesefactors on physical activity levels.

The rates of obesity observed in this study group (20%men, 16% women) are grounds for considerable concern.A further 5% of men and 9% of women are also extremely

overweight (BMI > 28kgm 2), indicting that current andfuture levels of obesity in Ireland may be among thehighest in Europe64. Undoubtedly, low levels of activityare associated with increased risk of weight gain andobesity65 and, on balance, the evidence from ecological,cross-sectional and prospective studies23'28'62'66"71 sug-gests that this may be a causal association. Whiledefinitive conclusions are not possible, neverthelessrecent evidence has shown that the relative impact of asedentary lifestyle in contributing to obesity may havebeen substantially underestimated72. Overall, the obesesubjects in this study had lower levels of activity butbecause of the cross-sectional approach of this study, it isunclear whether this is a causal association or a post hoceffect. The increased levels of household related activityby obese women are of interest, and suggest that they aremore successful and motivated than obese men atcompensating for their decreased levels of work andrecreational physical activity. It is not possible to concludeif their participation in these activities is simply aconsequence of their obesity, possibly caused by limita-tions in their physical and psychological well-being.Nevertheless, the fact that they are motivated toincrease physical activity levels in their own homescould usefully be exploited as a strategy to helpimprove adherence to exercise programmes to aidweight loss and maintenance73'74.

In conclusion, accurate assessment of patterns ofphysical activity is needed to properly inform publichealth policy aimed at promoting and sustaining lifetimehabits of physical activity. Since the health benefits ofphysical activity are linked principally to the total amountof energy expended, the type of activity performed is ofless significance. Occupational activity, sports, condition-ing activities, exercise, gardening and household tasks areall potentially beneficial. Consequently, the more holisticassessment of physical activity made in this study hashelped to highlight the complex, multidimensional natureof activity and, in particular, has revealed important andsubtle differences in the respective physical activitypatterns of men and women. The results have a clearand important public health message - simple popula-tion-focused programmes to promote physical activity areunlikely to offer the same chance of long-term success asmore sensitive and individualised strategies.

Acknowledgements

We thank the subjects who participated in the survey.

References

1 Lakka TA, Venalainen JM, Rauramaa R, Salonen R,Tuomilehto J, Salonen JT. Relation of leisure-time physicalactivity and cardiorespiratory fitness to the risk of acutemyocardial infarction in men. N. Engl. J. Med. 1994; 330:1549-54.

Physical activity patterns in Ireland 1115

2 Leon AS, Connett J, Jacobs DR, Rauramaa R. Leisure-timephysical activity levels and risk of coronary heart diseaseand death: the Multiple Risk Factor Intervention Trial. JAMA1987; 258: 2388-95.

3 Berlin JA, Colditz GA. A meta-analysis of physical activity inthe prevention of coronary heart disease. Am. J. Epidemiol.1990; 132: 612-28.

4 Hein HO, Suadicani P, Gyntelberg F. Physical fitness orphysical activity as a predictor of ischaemic heart disease? A17-year follow-up in the Copenhagen Male Study./. Intern.Med. 1992; 232: 471-9.

5 Sandvik L, Erikssen J, Thaulow E, Erikssen G, Mundal R,Rodahl K. Physical fitness as a predictor of mortality amonghealthy, middle-aged Norwegian men. N. Engl. J. Med.1993; 328: 533-7.

6 Morris JN, Clayton DG, Everitt MG, Semmence AM, BurgessEH. Exercise in leisure time: coronary attack and deathrates. Br. Heart J. 1990; 63: 325-34.

7 Powell KE, Thompson PD, Caspersen CJ, Kendrick JS.Physical activity and the incidence of coronary heartdisease. Ann. Rev. Public Health 1987; 8: 253-87.

8 American College of Sports Medicine. Position stand:physical activity, physical fitness, and hypertension. Med.Sci. Sports Exerc. 1993; 10: i-x.

9 Arroll B, Beaglehole R. Does physical activity lower bloodpressure? A critical review of the clinical trials. / . Clin.Epidemiol. 1992; 45: 439-47.

10 Manson JE, Nathan DM, Krolewski AS, Stampfer MJ, WillettWC, Hennekens CH. A prospective study of exercise andincidence of diabetes among US male physicians. JAMA1992; 268: 63-7.

11 Helmrich SP, Ragland DR, Leung RW, Paffenbarger RS.Physical activity and reduced occurrence of non-insulin-dependent diabetes mellitus. N. Engl. J. Med. 1991; 325:147-52.

12 Brooke-Wavell K, Jones PRM, Hardmann AE. Brisk walkingreduces calcaneal bone loss in post-menopausal women.Clin. Sci. 1997; 92: 75-80.

13 Cummings SR, Kelsey JL, Nevitt MC, O'Dowd KJ. Epide-miology of osteoporosis and osteoporotic fractures. Epide-miol. Rev. 1985; 7: 178-208.

14 Smith EL, Reddan W, Smith PE. Physical activity and calciummodalities for bone mineral increase in aged women. Med.Sci. Sports Exerc. 1981; 13: 60-4.

15 Albanes D, Blair A, Taylor PR. Physical activity and risk ofcancer in the NHANES I population. Am. J. Public Health1989; 79: 744-50.

16 Martinez ME, Giovannucci E, Spiegelman D, Hunter DJ,Willett WC, Colditz GA. Leisure-time physical activity, bodysize, and colon cancer in women: Nurses' Health StudyResearch Group./. Natl. CancerInst. 1997; 89: 948-55.

17 Lee I, Paffenbarger RS, Hsieh C. Physical activity and risk ofdeveloping colorectal cancer among college alumni. / . Natl.Cancer Inst. 1991; 83: 1324-9.

18 Taylor CB, Sallis JF, Needle R. The relationship of physicalactivity and exercise to mental health. Public Health Rep.1985; 100: 195-201.

19 Paffenbarger RS, Hyde RT, Wing AL, Hsieh CC. Physicalactivity, all-cause mortality, and longevity of college alumni.N. Engl. J. Med. 1986; 314: 605-13.

20 Paffenbarger RS, Hyde RT, Wing AL, Lee I-M, Jung DL,Kampert JB. The association of changes in physical-activitylevel and other lifestyle characteristics with mortality amongmen. N. Engl. J. Med. 1993; 328: 538-45.

21 Lee I-M, Hsieh CC, Paffenbarger RS. Exercise intensity andlongevity in men. The Harvard Alumni Health Study. JAMA1995; 273: 1179-84.

22 Villeneuve PJ, Morrison HI, Craig CL, Schaubel DE. Physicalactivity, physical fitness, and risk of dying. Epidemiology1998; 9: 626-31.

23 Prentice AM, Jebb SA. Obesity in Britain: gluttony or sloth?Br. Med.J. 1995; 311: 437-9.

24 Pavlou KN, Krey S, Steffee WP. Exercise as an adjunct toweight loss and maintenance in moderately obese subjects.Am.J. Clin. Nutr. 1989; 49: 1115-23-

25 Van Dale D, Saris WHM, ten Hoor F. Weight maintenanceand resting metabolic rate 18-40 months after a diet-exercise treatment. Int. J. Obes. 1990; 14: 347-59.

26 King AC, Frey-Hewitt B, Dreon D, Wood P. Diet versusexercise in weight maintenance: the effects of minimalintervention strategies on long term outcomes in men.Arch. Intern. Med. 1989; 149: 2741-6.

27 DiPietro L, Kohl HW, Barlow CE, Blair SN. Improvements incardiorespiratory fitness attenuate age-related weight gainin healthy men and women: the Aerobics Center Long-itudinal Study. Int. J. Obes 1998; 22: 55-62.

28 Rissanen AM, Heliovaara M, Knekt P, Reunanen A, AromaaA. Determinants of weight gain and overweight in adultFinns. Eur.J. Clin. Nutr. 1991; 45: 419-30.

29 Williams PT. Evidence for the incompatibility of age-neutraloverweight and age-neutral physical activity standards fromrunners. Am. J. Clin. Nutr. 1997; 65: 1391-6.

30 Killoran A, Fentem P, Casperson C. Moving On: Interna-tional Perspectives on Promoting Physical Activity. London:Health Education Authority, 1994.

31 US Department of Health and Human Services. PhysicalActivity and Health: a Report of the Surgeon General.Atlanta, GA: Centers for Disease Control and Prevention,National Center for Chronic Disease Prevention and HealthPromotion, 1996.

32 Crespo CJ, Keteyian SJ, Heath GW, Sempos CT. Leisure-timephysical activity among US adults. Results from the ThirdNational Health and Nutrition Examination Survey. Arch.Intern. Med. 1996; 156: 93-8.

33 Jones DA, Ainsworth BE, Croft JB, Macera CA, Lloyd EE,Yusuf HR. Moderate leisure-time physical activity. Arch.Fam. Med. 1998; 7: 285-9-

34 Health Education Authority (HEA) and Sports Council.Allied Dunbar National Fitness Survey, a Report on ActivityPatterns and Fitness Levels: Main Findings. London: SportsCouncil and HEA, 1992.

35 Health Promotion Agency for Northern Ireland. The North-ern Ireland Health and Activity Survey: Main Findings.Belfast: HMSO, 1994.

36 Colhoun H, Prescott-Clarke P, eds. Health Survey forEngland 1994. OPCS Health Survey No. 4. London:HMSO, 1996.

37 Department of Education. A National Survey of Involvementin Sport and Physical Activity. Dublin: Department ofEducation, Health Promotion Unit, 1996.

38 De Almeida MDV, Graca P, Afonso C, D'Amicis A,Lappalainen R, Damkjaer S. Physical activity levels andbody weight in a nationally representative sample in theEuropean Union. Public Health Nutr. 1999; 2: 105-13-

39 Cirera L, Tormo M-J, Chirlaque M-D, Navarro C. Cardiovas-cular risk factors and educational attainment in SouthernSpain: a study of a random sample of 3091 adults. Eur. J.Epidemiol. 1998; 14: 755-63.

40 Sallis JF, Hovell MF, Hofstetter CR. Predictors of adoptionand maintenance of vigorous physical activity in men andwomen. Prev. Med. 1992; 21: 237-51.

41 Harrington KE, Robson PJ, Kiely M, Livingstone MBE,Lambe J, Gibney MJ. The North/South Ireland FoodConsumption Survey: survey design and methodology.Public Health Nutr. 2001; 4(5A): 1037-42.

42 World Health Organization (WHO). Obesity: Preventingand Managing the Global Epidemic. Geneva: WHO, 1998.

43 Office of Population Censuses and Surveys. StandardOccupational Classification, Vol. 3. London: HMSO, 1991;39-53.

1116 MBE Livingstone et al.

44 Central Statistics Office. Census 96 Occupations. Dublin:Central Government Publications, 1998.

45 Ainsworth BE, Jacobs DR, Leon AS, Richardson MT,Montoye HJ. Assessment of the accuracy of physical activityoccupation questionnaire data. / Occup. Med. 1993; 35:1017-27.

46 Jacobs DR, Ainsworth BE, Hartman TL, Leon AS. Asimultaneous evaluation of 10 commonly used physicalactivity questionnaires. Med. Sci. Sport Exerc. 1993; 25: 8 1 -91.

47 Folsom AR, Caspersen CJ, Taylor HL, et al. Leisure timephysical activity and its relationship to coronary risk factorsin a population-based sample: the Minnesota Heart Survey.Am.J. Epidemiol. 1985; 121: 570-9.

48 Folsom AR, Jacobs DR, Caspersen CJ, Gomez-Marin O,Knudsen J. Test-retest reliability of the Minnesota LeisureTime Physical Activity Questionnaire. / . Chronic Dis. 1986;39: 202-11.

49 Ainsworth BE, Haskell WL, Leon AS, Jacobs DR, MontoyeHJ, Sallis JF, Paffenbarger RS. Compendium of physicalactivities: classification of energy costs of human physicalactivities. Med. Sci. Sports Exerc. 1993; 25: 71-80.

50 Stephens T, Jacobs DR, White CC. A descriptive epidemiol-ogy of leisure-time physical activity. Public Health Rep.1985; 100: 147-58.

51 Stephens T. Secular trends in adult physical activity:exercise boom or bust? Res. Q. Exerc. Sport 1987; 58:94-105.

52 Caspersen CJ. Physical activity epidemiology: concepts,methods, and applications to exercise science. Exerc. SportsSci. Rev. 1989; 17: 423-73.

53 Wareham NJ, Rennie KL. The assessment of physical activityin individuals and populations: why try to be more preciseabout how physical activity is assessed? Int. J. Obes. 1998;22(Suppl. 2): S30-8.

54 Wareham NJ, Hennings SHJ, Day NE, Prentice AM.Feasibility of heart-rate monitoring to estimate total leveland pattern of energy expenditure in a population-basedepidemiological study: the Ely young cohort feasibilitystudy. Br.J. Nutr. 1997; 78: 889-900.

55 Ainsworth BE, Richardson M, Jacobs DR, Leon AS. Genderdifferences in physical activity. Women Sport Phys. ActivityJ. 1993; 2: 1-16.

56 Cauley JA, LaPorte RE, Sandier RB, Schramm MM, KriskaAM. Comparison of methods to measure physical activity inpostmenopausal women. Am. J. Clin. Nutr. 1987; 45: 14-22.

57 Weller I, Corey P. The impact of excluding non-leisureenergy expenditure on the relation between physicalactivity and mortality in women. Epidemiology 1998; 9:632-5.

58 Richardson MT, Leon AS, Jacobs DR, Ainsworth BE, SerfassR. Comprehensive evaluation of the Minnesota LeisureTime Physical Activity Questionnaire. / . Clin. Epidemiol.1994; 47: 271-81.

59 DiPietro L. Physical activity, body weight, and adiposity: anepidemiologic perspective. Exerc. Sport. Sci. Rev. 1995; 23:275-303.

60 Blair SN, Kohl HW, Barlow CE. Physical activity, physicalfitness, and all-cause mortality in women: do women needto be active?/ Am. Coll. Nutr. 1993; 12: 368-71.

61 Mensink GB, Deketh M, Mul MD, Schuit AJ, Hoffmeister H.Physical activity and its association with cardiovascular riskfactors and mortality. Epidemiology 1996; 7: 391-7.

62 Fogelholm M, Mannisto S, Vartiainen E, Pietinen P.Determinants of energy balance and overweight in Finland1982 and 1992. Int.J. Obes. 1996; 20: 1097-104.

63 Livingstone MBE, Strain JJ, Prentice AM, Coward WA, NevinGB, Barker ME, Hickey RJ, McKenna PG, Whitehead RG.Potential contribution of leisure activity to the energyexpenditure patterns of sedentary populations. Br. J. Nutr.1991; 65: 145-55.

64 Seidell JC, Rissanen AM. Time trends in the world wideprevalence of obesity. In: Bray GA, Bouchard C, JamesWPT, eds. Handbook of Obesity. New York: Marcel Dekker,1998; 79-92.

65 DiPietro L. Physical activity in the prevention of obesity:current evidence and research issues. Med. Sci. Sports Exerc.1999; 3KSuppl.): S542-6.

66 Lissner L, Heitmann BL, Bengtsson C. Low-fat diets mayprevent weight gain in sedentary women: prospectiveobservations from the Population Study of Women inGothenburg, Sweden. Obes. Res. 1997; 5: 43-8.

67 Twisk JWR, Kemper HCG, van Mechelen M, Post GB, vanLenthe FJ. Body fatness: longitudinal relationship of bodymass index and the sum of skinfolds with other riskfactors for coronary heart disease. Int. J. Obes. 1998; 22:915-22.

68 Williamson DF, Madans J, Anda RF, Kleinman JC, Kahn HS,Byers T. Recreational physical activity and 10-year weightchange in a US national cohort. Int. J. Obes. 1993; 17:279-86.

69 French SA, Jeffery RW, Forster JL, McGovern PG, Kelder SH,Baxter JE. Predictors of weight change over two yearsamong a population of working adults: the Healthy WorkerProject. Int.J. Obes. 1994; 18: 145-54.

70 Haapanen N, Miilunpalo S, Pasanen M, Oja P, Vuori I.Association between leisure time physical activity and 10-year body mass change among working-aged men andwomen. Int.J. Obes. 1997; 21: 288-96.

71 Coakley EH, Rimm EB, Colditz G, Kawachi I, Willett W.Predictors of weight change in men: results from the HealthProfessionals Follow-Up Study. Int. J. Obes. 1998; 22: 89-96.

72 Wong MY, Day NE, Wareham NJ. Measurement error inepidemiology: the design of validation studies II: themultivariate situation. Stat. Med. 1999; 18: 2831-45.

73 King AC, Haskell WL, Taylor CB, Kraemer HC, Debusk RF.Group- vs home-based exercise training in healthy oldermen and women: a community-based clinical trial. JAMA1991; 266: 1535-42.

74 Perri MG, Martin AD, Leermakers SF, Sears SF, Notelovitz M.Effects of group- versus home-based exercise in thetreatment of obesity. / Consult. Clin. Psychol. 1997; 65:278-85.