We just came down hard on exercise. We established that it’s no one-way ticket to Slim Town, and that diet comes first. But even though exercise is largely futile on its own, it turns out that regular exercise is one of the most important habits you can possibly develop for long-term weight loss. (The good kind.)
The strongest evidence of this probably comes from the National Weight Control Registry (NWCR).
The National Weight Control Registry
The NWCR is a group of over 10,000 people (including me) who lost at least 30 pounds, kept the weight off at least a year, and are willing to share their story.1051 The average weight loss is 66 pounds, kept off for 5.5 years.1052 The goal is to figure out the common ground in this rare breed of weight losers—people who not only lost a lot of weight, but kept it off. (Most weight losers yo-yo.)
We regularly fill out questionnaires that assess what we did to lose weight, what we do now, and whether we’re keeping the weight off. For many years, our habits have been synthesized, collated, and analyzed. And the results are in.
There is a lot of variation, but some approaches were nearly universal. 98% of us changed our diet in some way. (Big surprise.) And 94% of us increased our level of physical activity.1053
Isn’t exercise useless for weight loss? By itself, usually. But as we saw last chapter, a combined diet and exercise program is the most effective weight-loss program.
And losing weight is only half the entrance requirement to the NWCR. The other half is maintaining weight loss.
And this is where exercise shines.
Many people go on diets and lose weight. In the next year, most of these people will regain one-third to two-thirds of the weight they lost. In the next five years, they will regain almost all of it.1054 Those are pretty depressing stats.
Only a small fraction of dieters—perhaps 15%1055—succeed at long-term weight loss. And studies indicate that regular exercise is crucial for long-term weight loss (also known as weight maintenance).1056,1057,1058,1059,1060,1061,1062
In a 2004 review, eight scientists concluded that exercise is “perhaps the best predictor of weight maintenance.”1063
The CDC’s website sums up the critical consensus:
Most weight loss occurs because of decreased caloric intake. However, evidence shows the only way to maintain weight loss is to be engaged in regular physical activity.1064
Translation: If you’re not willing to exercise regularly from now on, don’t even bother trying to lose weight.
Indeed, 90% of NWCR’ers continue to exercise regularly after they lose weight,1065 for 40 to 60 minutes per day, on average.1066,1067,1068
But don’t despair. I only work out two or three times a week, on average. You don’t have to be a fitness fanatic to get massive benefits from exercise.
It’s good to emulate people who succeeded at what you’re trying to succeed at. For someone trying to lose weight, there is probably no better approach than adopting habits that are nearly universal in people who succeed at long-term weight loss.
It’s a no-brainer. You need to make changes to your diet.
And you need to exercise regularly.
What’s Enough?
How much exercise is enough? Confusion sets in here. In studies, the link between physical activity and weight gain isn’t terribly consistent,1069 and it seems to take a lot of moderate exercise (around an hour a day)1070,1071 to prevent weight gain.
But this is to be expected. After all, when it comes to body weight, diet is the Big Kahuna. And as we’ve seen, it’s basically impossible to accurately capture someone’s diet from a questionnaire. Diet quality is likely a big enough confounding variable in these studies to almost completely mask exercise’s effects—so that only extreme exercisers seem to be able to keep weight off.
To illustrate, I gained 40 pounds of fat while doing vigorous workouts three days a week. But most days I was guzzling blue Powerade and eating processed foods, so the exercise didn’t matter.
The point isn’t that I might have avoided getting fat had I exercised for 75 minutes every day.
The point is that trying to fight a bad diet with exercise is bringing knives to a gun fight.
I don’t work out any more or any less today than I did when I got fat. My exercise levels were constant; exercise wasn’t the deciding factor in my getting fat. But it may have been a deciding factor in keeping the fat off once I lost it.
Evidence suggests that some people may need a lot of exercise to maintain their weight loss.1072 Being obese for a long time often causes long-term metabolic changes that persist for at least a year after weight loss1073 (and possibly much longer). To compensate for this, more exercise may be needed.
On the other hand, 25% of NWCR members maintain their weight loss with less than 30 minutes of moderate exercise per day, and 15% do less than 15 minutes of exercise per day.1074 There is no cookie-cutter amount (or type) of exercise that works for everyone. Some people may simply need less exercise to maintain weight loss than others.1075
Only you can figure out the right amount (and type) of exercise for you.
But the evidence is clear: anyone who wants to keep weight off should exercise regularly. “Regularly” means multiple times per week. Twice a week is probably the bare minimum.
And if you’re not planning on keeping the weight off, why bother?
Exercise and Evolution
Why is exercise so crucial to lifelong fat loss? It’s simple: we’re built to move.
For almost the entire past of the Homo genus—over two million years—we were hunter-gatherers.1076 Modern male hunter-gatherers seem to burn in the range of 600 to 1500 more calories per day from physical activity than the modern sedentary man.1077 Since hunting and gathering have always required lots of movement, it’s beyond question that we evolved doing lots of physical activity in those many millennia.
Evolution didn’t stop after agriculture, and is still occurring today.1078,1079
Have we evolved to be more sedentary since our cavemen days?
Contrary to popular belief, the average human may have become even more physically active after the dawn of agriculture.
Hunter-gatherers typically only spend two to three hours per day actively acquiring food1080 (though that is not their only physical activity).
On the other hand, before modern technology, farming tended to be an all-day-long, wildly physically demanding job—and still can be.
Based on data from various population samples of hunter-gatherers and farmers, scientists have concluded that the physical activity levels of these two groups are similar—and, if anything, farmers are slightly more physically active than hunter-gatherers.1081
In 2004, a pedometer (step-counter) study was done on an Amish farming community. The Amish are a traditionalist Christian group who don’t use electricity or gasoline, and lead simple lives.
10,000 steps per day is a popular goal of Fitbit users, and this amount of walking seems to have weight-management1082 and health-promoting1083 effects. How did the Amish stack up? The average Amish man took 18,425 steps per day, and the average Amish woman took 14,196 steps.1084
Even without the technological limitations of the Amish, it has been shown that modern Bolivian farmers burn more daily calories than Hadza hunter-gatherers.1085
The point is this: you are absolutely and unequivocally not adapted to a life of leisure.
The Modern Sloth
The extent of sedentary living today is truly unprecedented. In evolutionary terms, farming remained the most common profession until extremely recently. In 1790, 90% of Americans were farmers. Here’s how that number changed over time:
Sources:1086,1087
Even after the masses stopped farming, until quite recently, most jobs still required a decent amount of physical activity. Factory jobs used to be about as common as desk jobs are today, and were far more physically demanding. Only since the rise of computers have so many people had the luxury of sitting all day and staring at screens.
But it hardly stops at your job. Well into the 20th century, most people were forced to be active in ways it’s hard to fully appreciate today. Basic necessities like getting around, laundry, home care, dishes, shopping, and cooking required far more physical activity in days of yore—before cars, dishwashers, washing machines, ovens, and supermarkets made life easier.
Once-routine chores like chopping wood and fetching water were completely eliminated in the West, and technology made other chores—like lawn mowing and snow removal—far easier than they once were.
The plummeting of obligatory labor continued throughout the 20th century. In 1965, American women spent 25.7 hours per week on household activities (cooking, cleaning, laundry, etc.). By 2010, that number was 13.3 hours per week—a 48% decline.1088 Over the same period, women spent 99% more time on “screen-based media.”1089
Even buying food and supplies requires far less physical activity today. People used to walk to the local butcher, the baker, the candlestick maker.
Now they drive to the supermarket.
Soon, they may order all their groceries on Amazon.
Technology has slowly engineered nearly all the required physical activity out of our lives, and will only continue to do so. But regular physical activity is our native state. Our bodies are built for it. They don’t function properly without it.
You have to go out of your way to be active today.
But unless you do, your body won’t function properly.
Going from sedentary to active isn’t about “adding” something good to your life. It’s about restoring yourself—physiologically, metabolically, mentally, and spiritually—to the state in which you were built to exist.
This comes with a smorgasbord of health benefits.
Miracle
The Academy of Medical Royal Colleges issued a 2015 report that called exercise a “miracle cure” for the treatment and prevention of various diseases.1090 Indeed, as a paper in the Journal of Applied Physiology in the year 2000 stated:
With the possible exception of diet modification, we know of no single intervention with greater promise than physical exercise to reduce the risk of virtually all chronic diseases simultaneously.1091
Such superlatives are usually inappropriate in science.
In this case, however, they’re wholly justified.
How does exercise make you healthier? Let me count the ways.
Exercise boosts immunity,1092 reduces the risk of upper respiratory-tract infections,1093 and reduces systemic inflammation1094 (it lowers C-reactive protein, an inflammatory marker).
Exercise raises “good” HDL cholesterol,1095 lowers “bad” LDL cholesterol, and lowers triglycerides.1096
Exercise reduces blood clotting,1097,1098 significantly lowers blood pressure,1099,1100 and reduces the risk of stroke.1101
One meta-analysis found that active people were almost half as likely to die of heart disease.1102 In general, there is a dose-response relationship (the more, the better) between exercise and reduction in heart-disease risk.1103
Active people are 30-40% less likely to get colon cancer, and active women are 20-30% less likely to get breast cancer.1104
Physical activity probably reduces the risk of endometrial cancer, and may reduce the risk of prostate, stomach, and ovarian cancer.1105
Exercise prevents Type 2 diabetes,1106 and improves glycemic control in Type 2 diabetics.1107
Exercise improves the functional capacity of people with multiple sclerosis,1108 and is associated with a much lower chance of erectile dysfunction.1109 (A fact which will inspire many men more than the dramatic effects on heart disease, cancer, and death.)
Exercise reduces lower back pain,1110 reduces age-related loss of muscle mass1111 and aerobic capacity,1112 and reduces the risk of hip fractures,1113 arthritis,1114,1115 and osteoporosis.1116
Exercise improves memory1117 and cognitive performance,1118 and reduces the risk of Alzheimer’s1119 and Parkinson’s Disease.1120 Exercise improves depression treatment1121 and has an “antidepressant effect.”1122
Exercise improves sleep quality,1123 enhances body image,1124 reduces anxiety,1125 and makes people happier.1126,1127,1128,1129,1130,1131
Exercise significantly reduces the risk of dying from any cause (all-cause mortality) in a dose-dependent fashion, with a 19% risk reduction for people exercising 2.5 hours per week.1132
Independent of any effect on weight loss, exercise reduces waist circumference and intra-abdominal (“visceral”) fat.1133 Since exercise can cut fat and build muscle at the same time,1134 the bathroom scale isn’t always a reliable measure of progress; exercise can improve body composition without weight loss.1135
A 2015 study assessed ten sets of identical male twins in which one twin had exercised much more than the other twin over the previous three years. On average, the twin who exercised more had better insulin sensitivity, weighed less (despite having more lean body mass), had less body fat, and had more brain matter.1136
As noted in the textbook Advanced Exercise Physiology, “thousands of genes change expression during physical activity or inactivity,”1137 and “exercise induces dramatic changes in the hormonal mileu.”1138
This textbook goes on to state:
Physical activity is a natural cycle that is integrated into most other cycles in humans and animals. A disruption in the expected daily cycle of physical activity elicits disruptions in other cycles, leading to abnormal gene expression and systemic dysfunctions1139 … genes were optimized to support physical activity for survival. In the absence of historical physical activity levels, inherited genes “misfire” and function incorrectly.1140
Regular exercise fixes that.
And it can help fix you.
References
1051. The National Weight Control Registry. https://www.nwcr.ws/default.htm
1052. Wing, R. and Hill, J., “Successful Weight Loss Maintenance,” Annual Review of Nutrition 21 (2001): 323-41.
1053. “NWCR Facts,” National Weight Control Registry. https://www.nwcr.ws/Research/default.htm
1054. Dulloo, A., and Montani, J., “Pathways from Dieting to Weight Regain, to Obesity and the Metabolic Syndrome: An Overview,” Obesity Reviews 16, S1 (2015): 1-6.
1055. Ayyad C., and Andersen, T., “Long-Term Efficacy of Dietary Treatment of Obesity: A Systematic Review of Studies Published Between 1931 and 1999,” Obesity Reviews 1, no. 2 (2000): 113-119.
1056. Dombrowski et al., “Long Term Maintenance of Weight Loss with Non-Surgical Interventions in Obese Adults: Systematic Review and Meta-Anaylses of Randomised Controlled Trials,” BMJ 348 (2014): doi: https://dx.doi.org/10.1136/bmj.g2646
1057. Anderson et al., “Long-Term Weight Loss Maintenance: Meta-Analysis of US Studies,” American Journal of Clinical Nutrition 74 (2001): 579-584.
1058. Franz et al., “Weight-Loss Outcomes: A Systematic Review and Meta-Analysis of Weight-Loss Clinical Trials with a Minimum 1-Year Follow-Up,” Journal of the American Dietetic Association 107 (2007): 1755-1767.
1059. Ewbank et al., “Physical Activity as a Predictor of Weight Maintenance in Previously Obese Subjects,” Obesity Research 3, no. 3 (1995): 257-263.
1060. Pronk. N., and Wing, R., “Physical Activity and Long-Term Maintenance of Weight Loss,” Obesity Research 2, no. 6 (1994): 587-599.
1061. Hensrud et al., “A Prospective Study of Weight Maintenance in Obese Subjects Reduced to Normal Body Weight without Weight-Loss Training,” American Journal of Clinical Nutrition 60, no. 5 (1994): 688-694.
1062. Sciamanna et al., “Practices Associated with Weight Loss versus Weight Loss Maintenance,” American Journal of Preventive Medicine 41, no. 2 (2011): 159-166.
1063. Donnelly et al., “The Role of Exercise for Weight Loss and Maintenance,” Best Practice and Research: Clinical Gastroenterology 18, no. 6 (2004): 1009-29.
1064. “Physical Activity for a Healthy Weight,” Centers for Disease Control and Prevention. https://www.cdc.gov/healthyweight/physical_activity/
1065. “NWCR Facts,” National Weight Control Registry. https://www.nwcr.ws/Research/default.htm
1066. Catenacci et al., “Physical Activity Patterns Using Accelerometry in the National Weight Control Registry,” Obesity 19 (2011): 1163-1170.
1067. “NWCR Facts,” National Weight Control Registry. https://www.nwcr.ws/Research/default.htm
1068. Wing, R., and Phelan, S., “Long-Term Weight Loss Maintenance,” American Journal of Clinical Nutrition 82, no. 1 (2005): 222S-225S.
1069. Fogelholm, M., and Kukkonen-Harjula, K., “Does Physical Activity Prevent Weight Gain—A Systematic Review,” Obesity Reviews 1, no. 2 (2000): 95-111.
1070. I-Min Lee et al., “Physical Activity and Weight Gain Prevention,” JAMA 303, no. 12 (2010): 1173-79.
1071. Saris et al., “How Much Physical Activity Is Enough to Prevent Unhealthy Weight Gain? The Outcome of the IASO 1st Stock Conference and Consensus Statement,” Obesity Reviews 4, no. 2 (2003): 101-114.
1072. Catenacci et al., “Physical Activity Patterns in the National Weight Control Registry,” Obesity 16 (2008): 153-161.
1073. Sumithran et al., “Long-Term Persistence of Hormonal Adaptations to Weight Loss,” New England Journal of Medicine 365 (2011): 1597-1604.
1074. Catenacci et al., “Physical Activity Patterns in the National Weight Control Registry,” Obesity 16 (2008): 153-161.
1075. Catenacci et al., “Dietary Habits and Weight Maintenance Success in High versus Low Exercisers in the National Weight Control Registry,” Journal of Physical Activity and Health 11, no. 8 (2014): 1540-1548.
1076. Cordain et al., “Plant-Animal Subsistence Ratios and Macronutrient Energy Estimations in Worldwide Hunter-Gatherer Diets,” American Journal of Clinical Nutrition 71, no. 3 (2000): 682-692.
1077. Cordain et al., “Evolutionary Aspects of Exercise,” World Review of Nutrition and Dietetics 81 (1997): 49-60.
1078. Stearns et al., “Measuring Selection in Contemporary Human Populations,” Nature Reviews Genetics 11 (2010): 611- 622.
1079. Milot et al., “Evidence for Evolution in Response to Natural Selection in a Contemporary Human Population,” Proceedings of the National Academy of Sciences of the United States of America 108, no. 41 (2011): 17040-17045.
1080. Lindeberg, Staffan. Food and Western Disease: Health and Nutrition from an Evolutionary Perspective. Hoboken: Wiley-Blackwell, 2010. Kindle File, Chapter 4.6, Location 3474.
1081. Malina, R., and Little, B., “Physical Activity: The Present in the Context of the Past,” American Journal of Human Biology 20 (2008): 373-391.
1082. Schneider et al., “Effects of a 10,000 Steps per Day Goal in Overweight Adults,” American Journal of Health Promotion 21, no. 2 (2006): 85-89.
1083. Masataka et al., “Walking 10,000 Steps/Day or More Reduces Blood Pressure and Sympathetic Nerve Activity in Mild Essential Hypertension,” Hypertension Research 23, no. 6 (2000): 573-580.
1084. Basset et al., “Physical Activity in an Old Order Amish Community,” Medicine and Science In Sports and Exercise 36, no. 1 (2004): 79-85.
1085. Pontzer et al., “Hunter-Gatherer Energetics and Human Obesity,” PLOS One 7 (2012): e40503. doi:10.1371/journal.pone.0040503
1086. “Historical Timeline—Farmers and the Land,” Growing a Nation: The Story of American Agriculture. https://www.agclassroom.org/gan/timeline/farmers_land.htm
1087. “The 20th Century Transformation of U.S. Agriculture and Farm Policy,” Economic Information Bulletin 3. USDA. https://www.ers.usda.gov/media/259572/eib3_1_.pdf
1088. Archer et al., “45-Year Trends in Women’s Use of Time and Household Management Energy Expenditure,” PLOS One (2013): doi: 10.1371/journal.pone.0056620
1089. Ibid.
1090. “Exercise: The Miracle Cure and the Role of the Doctor in Promoting It,” Academy of Medical Royal Colleges. February 2015. https://www.aomrc.org.uk/wp-content/uploads/2016/05/Exercise_the_Miracle_Cure_0215.pdf
1091. Booth et al., “Waging War on Modern Chronic Diseases: Primary Prevention Through Exercise Biology,” Journal of Applied Physiology 88, no. 2 (2000): 774-787.
1092. Nieman, D., “Clinical Implications of Exercise Immunology,” Journal of Sport and Health Science 1, no. 1 (2012): 12-17.
1093. Nieman et al., “Upper Respiratory Tract Infection Is Reduced in Physically Fit and Active Adults,” British Journal of Sports Medicine 45 (2011): 987-992.
1094. Mattusch et al., “Reduction of the Plasma Concentration of C-Reactive Protein Following Nine Months of Endurance Training,” International Journal of Sports Medicine 21, no. 1 (2000): 21-24.
1095. Kodama et al., “Effect of Aerobic Exercise Training on Serum Levels of High-Density Lipoprotein Cholesterol: A Meta-Analysis,” JAMA Internal Medicine 167, no. 10 (2007): 999-1008.
1096. Halbert et al., “Exercise Training and Blood Lipids in Hyperlipidemic and Normolipidemic Adults: A Meta-Analysis of Randomized, Controlled Trials,” European Journal of Clinical Nutrition 53, no. 7 (1999): 514-522.
1097. Lamprecht et al., “Effects of a Single Bout of Walking Exercise on Blood Coagulation Parameters in Obese Women,” Journal of Applied Physiology 115, no. 1 (2013): 57-63.
1098. Kupchak et al., “Beneficial Effects of Habitual Resistance Exercise Training on Coagulation and Fibrinolytic Responses,” Thrombosis Research 131, no. 6 (2013): e227-e234.
1099. Whelton et al., “Effect of Aerobic Exercise on Blood Pressure: A Meta-Analysis of Randomized, Controlled Trials,” Annals of Internal Medicine 136, no. 7 (2002): 493-503.
1100. Cornelissen, V., and Smart, N., “Exercise Training for Blood Pressure: A Systematic Review and Meta-Analysis,” Hypertension (2013): doi: 10.1161/JAHA.112.004473.
1101. Lee et al., “Physical Activity and Stroke Risk: A Meta-Analysis,” Stroke 34 (2003): 2475-2781.
1102. Berlin, J., and Colditz, G., “A Meta-Analysis of Physical Activity in the Prevention of Coronary Heart Disease,” American Journal of Epidemiology 132, no. 4 (1990): 612-628.
1103. Sattelmair et al., “Dose Response between Physical Activity and Risk of Coronary Heart Disease: A Meta-Analysis,” Circulation 124 (2011): 789-795.
1104. Lee, I., “Physical Activity and Cancer Prevention—Data from Epidemiologic Studies,” Medicine and Science in Sports and Exercise 35, no. 11 (2003): 1823-1827.
1105. Steindorf et al., “Physical Activity and Primary Cancer Prevention,” Chapter 6: Physical Activity and Primary Cancer Prevention. Exercise, Energy Balance, and Cancer. New York: Springer Science+Business Media, 2013.
1106. Hu et al., “Epidemiological Studies of Exercise in Diabetes Prevention,” Applied Physiology, Nutrition, and Metabolism 32, no. 3 (2007): 583-595.
1107. Boule et al., “Effects of Exercise on Glycemic Control and Body Mass in Type 2 Diabetes Mellitus: A Meta-Analysis of Controlled Clinical Trials,” JAMA 286, no. 10 (2001): 1218-1227.
1108. White, L., and Dressendorfer, R., “Exercise and Multiple Sclerosis,” Sports Medicine 34, no. 15 (2004): 1077-1100.
1109. Cheng et al., “Physical Activity and Erectile Dysfunction: Meta-Analysis of Population-Based Studies,” International Journal of Impotence Research 19 (2007): 245-252.
1110. Hayden et al., “Meta-Analysis: Exercise Therapy for Nonspecific Low Back Pain,” Annals of Internal Medicine 142, no. 9 (2005): 765-775.
1111. Freiberger et al., “Physical Activity, Exercise, and Sarcopenia—Future Challenges,” Wiener Medizinische Wochenschrift 161, no. 17 (2011): 416-425.
1112. Kasch et al., “The Effect of Physical Activity and Inactivity on Aerobic Power in Older Men (A Longitudinal Study),” Physician and Sports Medicine 18, no. 4 (1990): 73-83.
1113. Gregg et al., “Physical Activity, Falls, and Fractures Among Older Adults: A Review of the Epidemiologic Evidence,” Journal of the American Geriatrics Society 48, no. 8 (2000): 883-893.
1114. Brosseau et al., “Efficacy of Aerobic Exercises for Osteoarthritis (Part II): A Meta-Analysis,” Physical Therapy Reviews 9, no. 3 (2004): 125-145.
1115. Baillet et al., “Efficacy of Cardiorespiratory Aerobic Exercise in Rheumatoid Arthritis: Meta-Analysis of Randomized Controlled Trials,” Arthritis Care & Research 62, no. 7 (2010): 984-992.
1116. Howe et al., “Exercise for Preventing and Treating Osteoporosis in Postmenopausal Women,” Cochrane Database of Systematic Reviews (2011): doi: 10.1002/14651858.CD000333.pub2.
1117. Roig et al., “The Effects of Cardiovascular Exercise on Human Memory: A Review with Meta-Analysis,” Neuroscience and Biobehavioral Reviews 37 (2013): 1645-1666.
1118. Chang et al., “The Effects of Acute Exercise on Cognitive Performance: A Meta-Analysis,” Brain Research 1453 (2012): 87-101.
1119. Radak et al., “Exercise Plays a Preventive Role against Alzheimer’s Disease,” Journal of Alzheimer’s Disease 20 (2010): 777-783.
1120. Chen et al., “Physical Activity and the Risk of Parkinson Disease,” Neurology 64, no. 4 (2005): 664-669.
1121. Silveira et al., “Physical Exercise and Clinically Depressed Patients: A Systematic Review and Meta-Analysis,” Neuropsychobiology 67 (2013): 61-68.
1122. Craft et al., “The Benefits of Exercise for the Clinically Depressed,” Primary Care Companion to the Journal of Clinical Psychiatry 6, no. 3 (2004): 104-111.
1123. Yang et al., “Exercise Training Improves Sleep Quality in Middle-Aged and Older Adults with Sleep Problems: A Systematic Review,” Journal of Physiotherapy 58, no. 3 (2012): 157-163.
1124. Campbell, A., and Hausenblas, H., “Effects of Exercise Interventions on Body Image: A Meta-Analysis,” Journal of Health Psychology 14, no. 6 (2009): 780-793.
1125. Wegner et al., “Effects of Exercise on Anxiety and Depression Disorders: Review of Meta-Analyses and Neurobiological Mechanisms,” CNS & Neurological Disorders—Drug Targets 13 (2014): 1002-1014.
1126. Penedo., F., and Dahn, J., “Exercise and Well-Being: A Review of Mental and Physical Health Benefits Associated with Physical Activity,” Current Opinion in Psychiatry 18, no. 2 (2005): 189-193.
1127. Stephens, T., “Physical Activity and Mental Health in the United States and Canada: Evidence from Four Population Surveys,” Preventive Medicine 17, no. 1 (1988): 35-47.
1128. Ahn, S., and Fedewa, A., “A Meta-Analysis of the Relationship Between Children’s Physical Activity and Mental Health,” Journal of Pediatric Psychology (2011): doi: 10.1093/jpepsy/jsq107.
1129. Hopkins et al., “Differential Effects of Acute and Regular Physical Exercise on Cognition and Affect,” Neuroscience 215 (2013): 59-68.
1130. Delextrat et al., “An 8-Week Exercise Intervention Based on Zumba® Improves Aerobic Fitness and Psychological Well Being in Healthy Women,” Journal of Physical Activity & Health 13, no. 2(2016): 131-139.
1131. Khazaee-pool et al., “Effects of Physical Exercise Programme on Happiness Among Older People,” Journal of Psychiatric and Mental Health Nursing 22, no. 1 (2015): 47-57.
1132. Woodcock et al., “Non-Vigorous Physical Activity and All-Cause Mortality: Systematic Review and Meta-Analysis of Cohort Studies,” International Journal of Epidemiology 40, no. 1 (2011): 121-138.
1133. Ross et al., “Exercise-Induced Reduction in Obesity and Insulin Resistance in Women: A Randomized Controlled Trial,” Obesity Research 12, no. 5 (2004): 789-798.
1134. Ibid.
1135. Catenacci et al., “The Role of Physical Activity in Producing and Maintaining Weight Loss,” Nature Clinical Practice Endocrinology & Metabolism 3 (2007): 518-529.
1136. Rottensteiner et al., “Physical Activity, Fitness, Glucose Homeostasis, and Brain Morphology in Twins,” Medicine & Science in Sports & Exercise 47, no. 3 (2015): 509-518.
1137. ACSM’s Advanced Exercise Physiology. Edited by Peter Farrell, Michael Joyner, and Vincent Caiozzo. Second Edition. Lippincott Williams & Wilkins, 2012. Page 693.
1338. Ibid., 520.
1139. Ibid., 690.
1140. Ibid., 695.