The Relationship Between Physical Activity and Health • Physical Activity • Any body movement resulting in a substantial increase in resting energy expenditure. • Exercise • Planned leisure-time physical activity structured to improve fitness. • Physical Fitness • A set of health or performance (skill) related attributes that allow an individual to perform physical activity. • A set of physiological attributes that results from participation in physical activity and, from genetic influences.
Throughout history physical activity has been an inevitable part of a person’s day. • We evolved to run, we now may be dysevolving • D. Lieberman, Harvard Anthropologist • We may not be living biologically normal lives
Today people can get by with doing very little activity. • Physical activity has been engineered out of daily living • Physically active jobs make up only about 25% of our workforce. Sedentary jobs have increased 83% since 1950. (American Heart Association, www.heart.org) • The importance of physical activity in improving and maintaining health has been recognized for centuries. • Physical education was developed over 100 years ago to promote physical activity.
In the past 60 years there has been an extensive amount of scientific research that has studied the physiological effects of exercise. • During this time there has been considerable interest in the effect of physical activity on health and well-being. • There is now a large body of evidence supporting the benefits of physical activity in preventing and treating a wide range of physical and psychological disorders.
Epidemiological Studies • Epidemiology: A scientific discipline that involves study of the distribution and determinants of disease in human populations. • Try to determine who is most likely to get a disease, and what factors may cause the disease. • Not easy to develop a link between physical activity and health. • In the past 50 years a considerable amount of epidemiological research has documented the positive influence of physical activity on health. • Recent studies are showing even more benefits of physical activity
There is currently an extensive amount of scientific research which indicates that inactivity is one of the most important causes of death, disability and reduced quality of life in industrialized nations. • Sedentary habits and low cardiovascular fitness are among the strongest predictors of premature death in the 21st century.
Paffenberger et al. 1986 • Studied Harvard alumni • Active men lived more than 2 years longer • Mortality reduced in men that played at least 3 hours of sports per week. • Men that became active their risk of dying by 15% (gained .72 yrs of life). • Other epidemiological studies looking at the relationship between occupational and physical activity with mortality, show that physical activity is an important independent predictor of mortality from all causes of CVD. • Morris (1950s), British civil servants • Taylor (1960s) US railroad employees
Several factors could have influenced these results. • Not all people respond the same to activity. • Some people with disease cannot be active. • Problems quantifying physical activity. • Contribution of other health risk factors. • Previous activity levels.
Physical Activity and Longevity • Research indicates that increasing physical activity in adulthood can improve the longevity of both men and women. • The more activity you do, the lower your risk of dying. • The greatest benefits are seen between the least active group and those that do a moderate amount of physical activity.
Life Expectancy • Life expectancy at birth represents the mean number of years a birth cohort (persons born in the same year) may expect to live given the present mortality experience of a population.
Canadian Statistics World Health Organization: 2011 • Male life expectancy at birth: 80 years (4th) • Female life expectancy at birth: 84 years (9th) • Overall 82 years (tied for 4th in the world) Retrieved June 1, 2013 World Health Organization • Male healthy life expectancy at birth: 70 years • Female healthy life expectancy at birth: 74 years • The WHO defines healthy life as follows: • “Healthy life expectancy is based on life expectancy, but includes an adjustment for time spent in poor health.”
B.C. Data, 2011 The average life expectancy in B.C. is 82.76 years. B.C. males have one of the highest life expectancy in the world at 80.65 years of age. B.C. women, still outlive B.C. men to 84.83 years.
Aging and Activity • It is dificult to quantify the effects of aging on physiological function and physical performance. • Some people physically deteriorate with age due to a lack of exercise, obesity, poor diet, smoking, and stress. • Some individuals are active and are still fit in their 50s, 60s and 70s.
Aging and Activity • Disease further complicates our understanding of the aging process. • arthritis, atherosclerosis • Physiological systems vary in the extent to which they deteriorate with age. • It is difficult to separate deconditioning and disease, from the aging process.
Aging and Activity • Lifestyle (diet, activity, exercise) will influence performance and health during aging, but they will not halt the aging process. • Life expectancy in 1900: 47 years 2000: 76 years 2011: 82 years • The maximum lifespan (100) has not changed • Quality of life is very important. North Americans only have healthy quality life during 85% of their lifespan.
Response to Activity • Older people readily adapt and respond to physical activity. • Endurance training helps maintain cardiovascular function, enhances exercise capacity, and reduces factors associated with heart disease, diabetes, and some cancers. • Strength training prevents loss of muscle mass and strength with aging.
Response to Activity • More important to exercise as you get older?? • Exercise prevents bone loss and improves postural stability, which the risk of fractures and falling. • Mobility exercises improve flexibility and joint health. • Exercise also provides psychological benefits. • Exercise does not retard the aging process, it just allows the person to perform at a higher level.
The Aging Process • Physiological control mechanisms are impaired in older people. • reaction time • resistance to disease • work capacity • recovery time • body structures are less capable and resilient • Very fit older individuals are still prey to the ravages of old age.
Genetic factors have a profound influence on the length of life, while environmental and lifestyle factors govern quality of life. • Life spans of identical twins are remarkably similar (2 - 4 yrs of each other). • nonidentical twins (7 - 9 yrs)
Physical Activity and Premature Death • Considerable evidence supports an inverse relationship between physical activity and mortality from CVD and cancer. • Inactivity is a major risk factor for: • Coronary heart disease • Stroke • Diabetes • Some cancers
Cardiovascular Disease • Affects nearly 120,000 Canadians • Heart disease and stroke are on par with cancer as the leading cause of death in Canada • Claims one life every 7 minutes • Heart attack and stroke are the most common life-threatening manifestations of CVD • Heart attack is the number one killer of Canadian women. • CVD is largely due to our way of life.
Physical Inactivity • Sedentary activity increases the risk for CVD • Physical activity reduces risk by: • Decreasing blood pressure and resting heart rate • Increasing HDL levels • Maintaining weight • Improving the condition of blood vessels • Helps prevent or control diabetes
There is overwhelming evidence that physical activity reduces the risk of CVD. • It is estimated that 35% of deaths from CVD are due to sedentary living. • Sedentary individuals have an 80% higher risk of dying from CVD than fit individuals. • There is a dose-response relationship between activity level and risk of CVD. • physical activity risk of CVD • largest risk of CVD with some activity
US Department of Health, 2008 • A comprehensive review on physical activity and health indicate that mortality risk is 20% to 30% lower among adults who achieve recommended amounts of physical activity • 150 min/week of moderate-intensity activity or • 75 min/week of vigorous intensity activity • Greater health benefits from higher amounts of activity
Sitting Time • A number of recent studies have found that sitting for protracted periods increases the risk of diabetes, heart disease and death. • Hours of sitting is detrimental to your health, even if you are physically active. Katzmarczyket al. (2009) • There is a dose-response gradient for higher mortality rates across incremental categories of daily sitting time among both inactive and active individuals.
High Blood Pressure Hypertension Systolic(mmHg) Diastolic (mmHg) Stage 1 140-160 or 90-99 Stage 2 160 and above or 100 and above • Risk factor for many forms of CVD • Too much force is exerted against arterial walls
High Blood Pressure • Causes Atherosclerosis • Chronic inflammatory response in artery walls • Accumulation of calcium and fatty materials • Form of Arteriosclerosis • thickening and hardening of artery walls
High Blood Pressure • Prevalence • 20% Canadian adults have hypertension • Only 66% have it controlled • 20% of Canadian adults have prehypertension • Incidence increases with age, oral contraceptive use, First Nations Canadian adults, African and South Asian descent • Treatment • Cannot be cured, but can be controlled • Have blood pressure tested once every two years
Physical Activity and Hypertension • Aerobic training resting and submax SBP, DBP and MAP (no change during max ex). • Aerobic exercise has been shown to SBP and DBP by 7mmHg in hypertensive patients. • Participation in vigorous sports the risk of developing hypertension by 30% in both males and females. • A meta-analysis (Katzmarzyk 2004) concluded that physically active individuals have a 24% lower risk of developing hypertension compared physically inactive individuals.
Physical Activity and Blood Lipids • Cut heart attack risk by 2% for every 1% reduction in total blood cholesterol levels. • Physical activity does not reliably total cholesterol and LDL. • Several studies have shown that physical activity can HDL. • HDL the risk of CVD by transporting cholesterol from the blood to the liver. • Physical activity has been shown to triglyceride levels in blood and the risk of CVD.
Obesity • Obesity progresses from the upper limit of normal (20% body fat for men and 30% body fat for women) to as high as 50 - 70% body fat in massively obese people. • Obesity has been linked to a variety of diseases including CVD, hypertension and cancers. • Risk of death from CVD is two to three times more likely in obese people (BMI > 30)
Health Implications of Overweight and Obesity • 33% rise in type 2 diabetes • ~ 21,000 premature deaths annually • Obesity is one of the six major controllable risk factors for heart disease. • Weight loss of 5-10% in obese individuals can reduce the risk of certain diseases.
Current Situation in Canada • The number of Canadians who are overweight or obese has steadily increased over the last 25 years. • Today, nearly one-quarter (24.0%) of adult Canadians, ~6 million people aged 18 or older, are obese. • An additional 37%(9 million) are overweight, bringing the total number of adult Canadians who are overweight or obese to over 60%. Overweight percentages are increasing every year.
Current Situation in Canada • Of even greater concern, 26% of Canadian children and adolescents aged 2 to 17 are overweight or obese (8% are obese). • For children aged 6 to 11 and adolescents aged 12 to 17, the likelihood of being overweight or obese tends to rise when the time spent watching TV, playing video games or computer use increases.
Current Situation in Canada • Research studies show that more than half of Canadian youth are not active enough for optimal growth and development. • Canadian girls are less active than boys with only 38% of girls and 48% of boys considered active enough.
Most experts believe that obesity results from an interaction among many factors. genetic psychological hormonal social environmental • It is increasingly recognized that inheritance is a factor in obesity and regional fat distribution.
Canadian Eating Habits • Recently 21% of Canadians reported their eating habits as fair or poor compared with 17% in 1997 and 15% in 1994. • We also know that those who eat fruit and vegetables less than 3 times a day are more likely to be obese than are those who consume such foods 5 or more times a day.
Recent Obesity ResearchFlegal, Jan 2013, JAMA • Severe obesity was associated with an increased risk of death from all causes, but lesser amounts of excess weight either did not increase the risk or appeared protective, according to the results of a systematic review and meta-analysis of 97 studies. • Adults with slightly higher body mass index may have a lower risk of mortality.
Relationship between Fitness and being Overweight • Research at the Cooper Clinic found that fit overweight men had the same life expectancy as fit thin men. • The fit overweight men reduced their risk of dying by 71% compared with a group of low fitness overweight men. • Thus overweight individuals can improve their life expectancy by improving their fitness.
Emerging research is questioning the "old school" thinking on obesity. • Research published in the New England Journal of Medicine in 1995 reported that women as little as 5 to 10% overweight had a 30 percent increase in risk of heart disease. • One reason for the results, and the link between obesity and health risks statistics, could be the effect of yo-yo dieting.
Ernsberger and Koletsky (1999) have induced high blood pressure in animals by forcing them to consume diets that made them gain and loose weight in a cyclic manner. • Other studies have linked diet pills with damage to heart muscle. • Another factor that could contribute to the correlation between health and obesity is the psychological stress that being obese in our society can cause. • A balanced diet and regular exercise is the best way to maintain a healthy body weight.
Physical Activity and Weight Loss • Research studies have clearly indicated that physical activity reduces the risk of becoming overweight. • Long-term exercise has been shown to improve the body’s ability to burn fat as a fuel. • Exercise will mobilize abdominal fat. • A significant number of calories can be burned with even moderate physical activity. • Metabolic rate remains elevated following an exercise session (both strength and aerobic sessions).
Exercise increases lean body mass and thus increases metabolic rate. • Exercise alone will produce only modest weight loss (~3kg). • Exercise has been shown to help maintain weight loss in obese children for more than 10 years after intervention. • Resistance training may help to increase lean muscle mass and maintain a healthy body weight.
Effects of aerobic and/or resistance training on weight loss in overweight and obese adults.Willis et al. JAP, 2012 • 119 sedentary, overweight and obese adults • 8 month exercise program • Divided into 3 groups: 1) RT- resistance training, 2) AT- aerobic training, 3) AT/RT - both • The AT and AT/RT groups reduced total body mass and fat mass (1–2% BF) more than RT (no loss). • RT and AT/RT increased lean body mass more than AT.
Balanced Diet and Exercise • Best method to produce and maintain weight loss. • Will accelerate weight loss. • Provide protection against a significant loss of lean tissue usually observed when weight loss is achieved by diet alone. • By reducing stress, boredom, and tension exercise can considerably reduce the amount of food consumed in response to these influences.
Diet Epidemiology Study • Nurse’ Health Study (1976) followed 121,700 nurses • Second cohort of 116,000 nurses in 1989 • Harvard hospitals • Examined the effects of smoking, alcohol consumption and diet
Current Situation in Canada • Physical inactivity costs the Canadian health care system at least $2 billion annually in direct health care costs, and the estimated annual economic burden is $5 billion. • For the majority of Canadians, current physical activity patterns are not optimal for health.
Diabetes • Doubles the risk of CVD for men. • Triples the risk of CVD for women. • Most common cause of death in adults with diabetes.