Evolution of Inactivity PDF

9/12/2024 1 The human genome is “All that we can do, is keep steadily in mind that each organic programmed being is striving… the vigorous, the healthy and the happy...

9/12/2024 1 The human genome is “All that we can do, is keep steadily in mind that each organic programmed being is striving… the vigorous, the healthy and the happy survive and multiply.” FOR -Charles Darwin, The Origin of Species Physical Activity 2 1. Human architecture is “made for Humans are ENGINEERED for movement” Physical Activity: The Evidence Skeleton Joints Muscles 2.Organism can adapt to a wide range of metabolic demands imposed on the body 3.Physical work “was” necessary to promote survival of the species 4.Low-levels of activity are associated with loss of function, disease and death 3 1  9/12/2024 Evolution of Physical Activity Evolutionary history teaches us that early humans could not have survived without the ability to perform very demanding physical work All of the adaptations to physical activity improve performance and thus increased chance of survival. – Cardiovascular system improved transport of O2 rich blood to the tissues – Muscles Growth and improved metabolism at the cell – Nervous System and Brain Improved coordination and efficiency Improved cognitive function and memory 4 Physical Activity necessary for hunting and survival Adaptations result in More food = nutrients improved performance for survival, energy and capacity, motor skill physical development and cerebral functions Improved performance Increased success rate and motor skill results in more food increases hunting success rate 5 Cardiovascular Activity Resistance Training Walking Carrying – Gathering – Children – Hunting – Game meat – Visit other communities – Firewood Running Lifting – Chasing wounded prey – Game carcasses Dancing – Walls for shelter – Entertainment Digging – Rituals – Roots – Holes 6 2  9/12/2024 1. Hunting and Gathering 2. Agricultural Revolution DAILY PHYSICAL ACTIVITY 3. Industrial Revolution 4. Technology Revolution Technology Continuum Human genome is 98.4% similar to that during Hunting and Gathering 7 8 Homo Sapien- Hunter/Gatherer Today’s Western Human Avg- 126 lbs Avg- 176 lbs PA RELATED EE 10.2 kcal/lb/day 3.0 kcal/lb/day 1285 kcal/day 528 kcal/day 11-13 miles of walking/jogging 4-6 miles of walking /jogging 9 3  9/12/2024 Late stone-agers were smaller but much more muscular than typical “westernized” contemporary human beings – Why? Today’s daily energy expenditure is 65% that of late stone-agers – When adjusting for body size, current daily EE is 38% that of late stone-agers. Current public PA guidelines for health require only 44% the daily EE of contemporary hunter/gatherer societies. 10 Hunter Gatherer Populations were: Faster Some evidence predicts speeds like Usain Bolt VO2max comparable to modern day athletes – Both due to fitness and smaller size 20% stronger than modern day athletes Skeletons similar to modern day athletes Lower waist circumference and body-fat% 11 PAL= TOTAL ENERGY BURNED IN 24 HOURS (calories) BASAL METABOLIC RATE 12 4  9/12/2024 Population characteristics, energy expenditure, and body composition. Contemporary Hunters/Gatherers vs. Western Adults vs. Farmers Pontzer H, Raichlen DA, Wood BM, Mabulla AZP, Racette SB, et al. (2012) Hunter-Gatherer Energetics and Human Obesity. PLOS ONE 7(7): e40503. https://doi.org/10.1371/journal.pone.0040503 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0040503 13 Mechanisms of Survival Thrifty Gene Hypothesis – “allows hunters/gatherer’s to efficiently store excess energy and better survive through periods of famine and food scarcity” Relationship with physical activity and feasting – If excess activity results in finding food= rest time! Glycogen stores increase Fat oxidation decreases – If exercising during fasting? Lose glycogen stores Fat oxidation increases Long-term= decrease in performance How do these mechanisms interact with today’s lifestyle? 14 Biological basis for the hypothesis that the human genome requires physical activity to maintain health is depicted. As a consequence, genes Booth F W et al. J Appl Physiol 2002;93:3-30 expecting physical activity for normal function have altered expression such that clinical disorders appear. ©2002 by American Physiological Society 15 5  9/12/2024 What determines our PA level (today)? Genetic Core explains: 20% of PA and 40% CRF Host (the person) likes, dislikes, motivation etc. Natural and built Environment environments: parks, weather, homes, neighborhoods etc. Gender, Age, Disease status etc. Resources, attitudes, support, socioeconomic status, exposure to technology, crime etc. 16 Evolutionary Paradox The humans quest to make things more efficient has removed the need for physical activity. 17 Change the Paradigm Exercise is Good For You 18 6