Pedometers and Public Health Catrine Tudor-Locke, PhD, FACSM Associate Professor of Health Promotion Walking Research Laboratory Department of Exercise and Wellness Arizona State University

Internal Mechanism

Mass Distribution is Not the Answer  Hardware Pedometer  Software Guidelines Protocols Detailed program templates

Practical Pedometry  Expected values  Standard protocols  Screening  Surveillance  Program evaluation  Step indices  Intervention tool

Summary of validity evidence  Review of 25 articles since 1980 median r=.86 with different accelerometers median r=.82 with time in observed activity median r=.68 with different measures of energy expenditure median r=-.38 with self-reported sitting time median r=.33 with self-reported physical activity Tudor-Locke et al., Sports Med 2002

Tudor-Locke et al., MSSE 2002 Free-living: Pedometer vs. accelerometer

Effects of walking speed Speed (m/min) Le Masurier, Keup, Tudor-Locke Medicine and Science in Sport and Exercise, 2004

Can we use pedometers with older adults?  26 nursing home residents and 28 similarly aged community dwelling older adults  Self-selected walking at slow, normal, fast paces  Pedometers underestimated actual steps taken in dependent older adults by 74% (slow) to 46% (fast).  The percent error for the independent older adult sample ranged from 25% (slow) to 7% (fast). Cyarto, Myers, and Tudor-Locke Medicine and Science in Sport and Exercise, 2004

Pedometer vs. dual-mode CSA  Motor vehicle travel on paved roads total distance traveled was 32.6 km or 20.4 miles  Any steps detected during motor vehicle travel were considered error  the CSA detected approximately 17-fold more erroneous steps than the pedometer approximately 250 vs 15 steps for the total distance traveled, P <.05 Le Masurier and Tudor-Locke MSSE 2003

Can we use pedometers with obese people?  16 normal weight, 8 overweight, 11 obese  Self-selected walking at slow, normal, fast paces  Percent error (NS) normal weight= 2.64.2% overweight=1.72.8% obese=4.04.3% Elsenbaumer and Tudor-Locke, Medicine and Science in Sport and Exercise, 2003

Distributions Tudor-Locke et al., Medicine and Science in Sport and Exercise, 2004

Patterns Tudor-Locke et al., Annals of Behavioral Medicine, 2004

Breaking down the patterns Tudor-Locke et al., Research Quarterly for Exercise and Sport, 2001

How Many Steps are Enough?

Legend 1=8-10 year olds 2=14-16 year olds 3= Healthy younger adults (approx years) 4= Healthy older adults (>50 years) 5= Individuals living with disabilities and chronic illnesses Tudor-Locke, Research Digest, 2002

Sedentary lifestyle index Tudor-Locke et al., International Journal of Obesity, 2001

How Many Steps Are Equivalent to Current Public Health Recommendations?

The Evidence  3,800-4,000 steps in 30 minutes extrapolated from distance walked data at different paces set externally (Welk et al., 2000)  3,100 steps during unsupervised 30 minute walk (intensity not reported) included in a typical day of activity (Wilde et al., 2001)  3,400 steps during 30 minute group continuous group walk at self-selected pace (Tudor-Locke et al., 2001)

Controlled Conditions Tudor-Locke et al., Canadian Journal of Applied Physiology, in press

Controlled conditions (continued) Activity intensity Steps/min MalesFemales Light (  2.99 METs) <96<107 Moderate ( METs) Hard ( METs) Very Hard (  9.0 METs)>153>162

Field conditions: Self-select moderate pace  3,600 steps in 30 minutes of self- paced moderate intensity walking (ICC=.96)  No difference in steps taken based on gender Tudor-Locke et al., in progress

The latest….  Dose Response to Exercise in Women (DREW)  8kcal/kg/week = 100% of public health recommendations  Free-living activity 4600 steps/day  5500 steps/session, 3 days/week Jordan et al., Medicine and Science in Sports and Exercise, 2005

Modeling change  Baseline = 5000 steps/day  30 minute walk, 3 days/week = 6200 steps/day (60 min/3 days =7500/steps/day)  30 minute walk, 5 days/week = 7100 steps/day (60min/5days = 9200 steps/day)  30 minute walk, 7 days/week = 8000 steps/day (60 min/7days =11000 steps/day)

Is a Universal 10,000 Steps/day Sustainable?

Pedometer-based Interventions  Yamanouchi et al. (1995) RCT First to look at 10,000 step/day goal Dieting patients (living in hospital) with type 2 diabetes took 19,200 steps/day and lost 17lbs over 6-8 weeks compared to control group that averaged 4,000 steps/day and lost 9 lbs

Seems Reasonable for Healthy Adults  Assembled from published literature, healthy adults take between 7,000-13,000 steps/day (Tudor-Locke and Myers, 2001)  73% of participants who reported 30 minutes of moderate activity also achieved 10,000 steps (Welk et al., 2000)

However….  Even with a prescribed walk, 38-50% of sedentary women reached 10,000 steps on any single day (Wilde et al., 2001)  Only half of healthy older exercisers ever achieved 10,000 steps on any single day, despite the fact that they participated in exercise class or informal walking for exercise on most days of observation (Tudor-Locke et al., 2002)

Further…  When all accumulated minutes are considered, guidelines can be achieved within as little as 8000 steps/day (Tudor- Locke et al., 2002)  Although individuals achieving >10,000 steps/day are more likely to achieve guidelines, that alone is not a guarantee of meeting them (Le Masurier et al., 2003)

And….  Iwane et al. (2000) described experiences implementing a 10,000 step/day program in a manufacturing work place  730 volunteered to participate out of 2474 workers (approximately 30%)  306 remained in program after 4 weeks (42% drop out)  Only 83 remained after 12 weeks (89% drop out from beginning of program)

Remaining Concerns

Too Low for Children  8-10 year olds in the U.K. take 12,000-16,000 steps/day (Rowlands et al., 1999)  6-12 year olds in the U.S. take 11,000-13,000 steps/day (Vincent et al., 2002)  years olds in the U.S. take 11,000-12,000 steps/day (Wilde, 2002)

BMI-referenced cutpoints  International sample (USA, Sweden, Australia) 995 girls, 959 boys, 6-12 years  Criterion referenced analysis approach  12,000 steps/day for girls  15,000 steps/day for boys Tudor-Locke et al., Preventive Medicine, 2004

Too High for Sedentary Individuals  Assembled from published literature: 3,500-5,500 steps/day for individuals living with disabilities and chronic illnesses (Tudor-Locke and Myers, 2001)  Proposed sedentary lifestyle index is <5,000 steps/day (Tudor-Locke et al., 2001)  Achieving 10,000 steps/day requires a 2-3 fold increase in daily activity

What are We Left With?

Preliminary guidelines for adults  >12,500 steps/day highly active  >10,000 steps/day active  7,500-9,999 steps/day somewhat active  5,000-7,499 steps/day low active  <5,000 steps/day sedentary Tudor-Locke & Bassett, Jr., Sports Medicine, 2004