Sedentary Behavior and Physical Activity: Independent, Co dependent or Irrelevant? Harold W. (Bill) Kohl, III, Ph.D., MSPH University of Texas Health Science Center Houston School of Public Health Michael and Susan Dell Center for Healthy Living The University of Texas at Austin Department of Kinesiology and Health Education USA @billkohl #physicalactivity
Acknowledgments Capt. Richard Troiano Ms. Heather Steele ILSI Energy Balance Committee
Overview Definition and framework Existing research Recommendations
Children s Games, Pieter Bruegel the Elder, 1560
Current situation
Children s Games, Pieter Bruegel the Elder, 1560
Current situation
180 Growth in Sedentary Science Enter Sedentary Behavior Publications 160 140 120 100 80 60 40 20 0 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Scopus.com Articles or reviews: sedentary AND time OR behavior in title
Enter Sedentary Behavior Measurement Measurement Measurement
Enter Sedentary Behavior Television time Sitting time Screen time Sleep Occupational Transportation
Definition of Sedentary Behavior Activities that do not increase energy expenditure substantially above the resting level. Such as sleeping, sitting, lying down, and watching television, and other forms of screen based entertainment. Operationally, sedentary behavior includes activities that involve energy expenditure at the level of 1.0 1.5 metabolic equivalent units (METs). Light physical activity, is often grouped with sedentary behavior but is in fact a distinct activity construct Such as slow walking, sitting and writing, cooking food, and washing dishes. Involves energy expenditure at the level of 1.6 2.9 METs. Pate et al 2009
Exercise Leisure Occupation Specific Activity Type e.g., soccer, lifting heavy boxes or children, walking Frequency Intensity Household Domestic Self Care Transport Intensity Category e.g., light, moderate, vigorous Duration Pattern Physical Activity Recall Cue Characteristic Gabriel et al 2011
Leisure Occupation Specific Behavior Type Sitting, laying, sleeping Frequency Volume Type Sleep Transport Context Duration Pattern Physical Inactivity Recall Cue Characteristic Kohl and Troiano unpublished
Whitfield et al 2013
Whitfield et al 2014
Competitive runners sit more than 10 hours/day! Whitfield et al 2014
Jefferis et al 2014
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Inactivity All adults should avoid inactivity. Some physical activity is better than none, and adults who participate in any amount of physical activity gain some health benefits.
Sitting Time Prospectively Associated with Early Mortality Katzmarzyk et al 2009
independent of physical activity Katzmarzyk et al 2009
Standing Time Prospectively Associated with Early Mortality Katzmarzyk 2014
but not independent of physical activity Katzmarzyk 2014
Biswas et al 2015
Sedentary behavior and noncommunicable disease outcome 2.5 2.0 Hazard Ratio 1.5 1.0 0.5 0.0 All cause mortality CVD mortality CVD incidence Cancer mortality Cancer incidence Diabetes incidence Adapted from Biswas et al 2015
Sedentary behavior, physical activity and all cause mortality 2.5 2.0 Low Activity/ High Sedentary High Activity/ High Sedentary Hazard Ratio 1.5 1.0 * * * 1.46 1.16 0.5 * 0.0 Seguin et al 2014 Patel et al 2010 Pavey et al, 2012 Kim et al, 2013 van der Ploeg et al, 2012 Matthews et al, 2012 Adapted from Biswas et al 2015
Association being driven by pre existing disease? Especially cardiometabolic disease? Van der Ploeg et al 2013
Physical Activity and Health Conceptual Framework Health Outcomes Physical Activity Exposure Intensity Cardiovascular/ Respiratory Health (including CHD, PVD, Stroke) Metabolic Health (including Diabetes Mellitus and Obesity) Musculoskeletal Health (including Osteoporosis) Cancers Functional Health Mental Health All-Cause Mortality Frequency Examples Examples Examples Examples Examples Examples Examples Duration Pattern Type Dyslipidemias Blood Pressure Hemostatic/ Coagulation Factors Asthma Fitness Cardiac Function Lung Function Insulin Resistance Insulin Sensitivity Glucose uptake Metabolic Syndrome Overweight Constipation Fitness Hormonal influences Sleep quality Bone mineralization Flexibility Strength Balance Maturation/ Growth Fitness Motor skill development Muscle fiber Bowel transit time Hormonal factors Immune Function Linkages with other behaviors. Quality of life Functional independence Balance Pain Fall prevention Cognitive Function Anxiety Self-concept Sleep quality Strength Balance Fitness Previous Injury Family history Risk Factors Caloric Expenditure Adverse events and Risks of Physical Activity
Physical Inactivity, Sedentary Behaviors and Health Conceptual Framework Physical Inactivity Health Outcomes Volume of inactivity Frequency Duration Cardiovascular/ Respiratory Health (including CHD, PVD, Stroke) Metabolic Health (including Diabetes Mellitus and Obesity) Musculoskeletal Health (including Osteoporosis) Cancers Functional Health Mental Health All-Cause Mortality Volume of physical activity Pattern Timing Examples Dyslipidemias Blood Pressure Hemostatic/ Coagulation Factors Asthma Fitness Cardiac Function Lung Function Examples Insulin Resistance Insulin Sensitivity Glucose uptake Metabolic Syndrome Overweight Constipation Fitness Hormonal influences Sleep quality Examples Bone mineralization Flexibility Strength Balance Maturation/ Growth Fitness Motor skill development Muscle fiber Examples Bowel transit time Hormonal factors Immune Function Linkages with other behaviors. Examples Quality Pain of life Functional ADL independence FHQoL Balance Pain Fall prevention Cognitive Function Examples Anxiety Self-concept Sleep quality Type Sedentary Behavior Mechanisms Kohl and Troiano unpublished
Conclusions Sedentary behavior has been measured/used in a variety of ways. Can make up a large portion of a day, even for very active people. A consistent definition and framework for research must be applied. Data suggest some kind of independent association (or not) with health outcomes sitting, not standing. Unclear if it is real or an artifact of measurement. Early mechanistic studies suggest directions but none support independent associations.
Recommendations Although the full range of activity intensities (sedentary to vigorous) contribute to total energy expenditure, activity performed within a narrow intensity range (e.g., vigorous) may influence health in ways that are unique from other activity intensities. Conclusions of studies should be phrased carefully so as to be consistent with the activity variables that were actually measured in the study. Care should be taken to avoid discussing replacing reduction in sedentary behavior for meeting physical activity guidelines. Mechanistic studies are urgently needed. Physiologic principles of overload, specificity and adaptation still apply.
Physical Inactivity, Sedentary Behaviors and Health Conceptual Framework Physical Inactivity Health Outcomes Volume of inactivity Frequency Duration Cardiovascular/ Respiratory Health (including CHD, PVD, Stroke) Metabolic Health (including Diabetes Mellitus and Obesity) Musculoskeletal Health (including Osteoporosis) Cancers Functional Health Mental Health All-Cause Mortality Volume of physical activity Pattern Timing Examples Dyslipidemias Blood Pressure Hemostatic/ Coagulation Factors Asthma Fitness Cardiac Function Lung Function Examples Insulin Resistance Insulin Sensitivity Glucose uptake Metabolic Syndrome Overweight Constipation Fitness Hormonal influences Sleep quality Examples Bone mineralization Flexibility Strength Balance Maturation/ Growth Fitness Motor skill development Muscle fiber Examples Bowel transit time Hormonal factors Immune Function Linkages with other behaviors. Examples Quality Pain of life Functional ADL independence FHQoL Balance Pain Fall prevention Cognitive Function Examples Anxiety Self-concept Sleep quality Mood Type Sedentary Behavior Mechanisms Kohl and Troiano unpublished
Enter Sedentary Behavior Mechanisms Mechanisms Mechanisms
Mechanisms? Aerobic capacity Skeletal muscle metabolism and function Telomeres/genetic stability Cognitive function Overload, Specificity, Adaptation
Dunstan et al 2012 n=19 overweight/obese adults Age 45 65 years Three treatment crossover trial: Uninterrupted sitting Sitting with 2 min bouts of light intensity physical activity every 20 mins Sitting with 2 min bouts of moderate intensity physical activity every 20 mins Glucose tolerance test area under curves for insulin and glucose
24 30% reduction in plasma glucose AUC after activity break conditions increased insulin sensitivity? 2 h post load glucose highest in Uninterrupted Sitting condition Dunstan et al 2012
23% reduction in insulin AUC after activity break conditions reduced insulin secretion? Dunstan et al 2012
Thorp et al 2014 n=23 overweight/obese adults Age 45 65 years Five day simulated office environment crossover: Seated work for 8 hours Interchanging seated and standing every 30 mins Glucose tolerance test area under curves for insulin and glucose; triglyceride response.
Differences in change in glucose AUC but not insulin increased insulin sensitivity? Thorp et al 2014
Thosar et al, 2014 12 non obese men 24.2 years of age (mean) Two randomized 3 hour sitting trials Sitting 3 hours uninterrupted Sitting interrupted by 5 min treadmill breaks at 30 mins and at each hour (2 mph). Superficial femoral artery flow mediated dilation and shear rate
Thosar et al 2014 Decline in FMD attenuated with active breaks
Sjögren et al, 2014 n=49 sedentary, overweight men and women 68 years of age (mean) 6 month clinical trial of individualized physical activity intervention. Treatment behavioral intervention Control Blood cell telomere length analyzed by changes in time spent in physical activity and by changes in time spent sitting. Sitting time measured using short IPAQ.