Benefits of exercise: a review of the research and a plan for prescribing exercise programs

Transcription

1 Benefits of exercise: a review of the research and a plan for prescribing exercise programs How many of your patients would take a pill that would do the following Christine Kramer, ANP Decrease their risk of premature mortality Decrease their risk of cardiovascular disease Decrease their risk of developing hypertension Improve blood pressure control if they are hypertensive Decrease their risk of stroke Decrease their risk of colon and breast cancer Decrease their risk of diabetes mellitus Improve their glycemic control if they have DM Decrease their risk for depression and anxiety Improve their depressive/anxious symptoms Decrease their risk of osteoporosis and hip fracture Improve their functional status as they age Improve their lipid profile Decrease their risk for erectile dysfunction Decrease their risk for developing dementia Help them lose weight Help them to maintain weight loss Increase their metabolic rate by increasing their lean body mass Help improve their QUALITY OF LIFE How big is the problem of inactivity? 56.5% of adults were reported as inactive in the National Health Survey (2008) 55% of waking hours in children and adults were spent in sedentary behaviors in National Health and Nutrition Examination Survey ( )-this increased to 58% in The cost of physical inactivity to US economy was estimated at 13.8 billion dollars in 2008 The World Health Organization has identified physical inactivity as the fourth leading risk factor for morality globally What is the effect of exercise on mortality? Most of the data is from observational trials Study done of Harvard College Alumni (10,269 men) demonstrated that those who engaged in moderately vigorous exercise had 23 % lower risk of death Study of 250,000 men and women aged years demonstrated a 50% decrease in mortality risk in people who engaged in vigorous, regular exercise (Leitzman et al., 2007) 1

2 What is the effect of exercise on cardiovascular disease? Data from the Framingham heart study observed differences in life expectancy: Men who were moderately-highly active increased life expectancy by 3.7 years, less active 1.7 Women who were moderately-highly active increased life expectancy by 3.5 years, less active 1.5 It was also observed that there was a decrease in mortality in people who moved from sedentary to active later in life The Nurses Health Study women with DM type II had a 40% lower risk of CV disease if they spent at least 4 hours a week performing moderate (including walking) or vigorous exercise The Nurses Health Study also demonstrated that brisk walking or vigorous exercise was inversely related to the risk of a coronary event-this was graded depending on amount of exercise performed The Women s Health Initiative Observational Study 73,743 women aged years studied exercise in the prevention of cardiovascular events Increasing physical activity had a strong, graded, inverse association with coronary heart disease and CV events Both walking and vigorous exercise were associated with substantial reductions in the incidence of CV events Prolonged sitting predicted increased CV risk The Harvard College Alumni study demonstrated a reduction of CV risk of 23% in men (10,269 participants) who engaged in moderately vigorous sports activities (30 min/day most days of week) Study by Lee et al. (2014) examined running with allcause and cardiovascular mortality risks in 55,137 adults over 15 years Running even 5-10 min/day and at slow speeds <6 miles/hr was associated with markedly reduced risks of death from all causes and cardiovascular disease What effects does exercise have on the CV system? Reduction of resting and exercise heart rate Reduction of resting and exercise blood pressure Reduction of myocardial oxygen at submaximal levels of physical activity Increase in stroke volume, myocardial contractility Increased endothelium-dependent vasodilation Enhanced parasympathetic tone Improved lipid profile Increases the coronary artery lumen diameter Increases the anginal threshold Decreases inflammatory markers What is the effect of exercise on diabetes mellitus? Prevention: In a study done by Lynch et al. there was 64% reduction in development of DM in a high risk group of men (overweight, positive parental history, HTN, impaired glucose tolerance) In the Nurses Health Study data was examined from 70,102 participants that did not have DM at the onset Greater physical activity was associated with a substantial reduction in the risk of developing DM-the risk was reduced further with increasing amounts of exercise 2

3 Benefits of exercise on DM cont. Effects of exercise on DM cont. The Diabetes Prevention Program with 3234 non diabetic persons at high risk of developing DM Groups: Control, Metformin 850mg twice daily or they had lifestyle intervention (weight loss 7% and exercise 150 min/wk) Results: Incidence of DM: 11.0, 7.8, 4.8 cases per 100 both interventions were effective but lifestyle was the MOST effective Treatment: Exercise improves glycemic control Review of 47 RCT s demonstrated a decrease in HgbA1c between o.5-0.8% Trial done with 251 adults randomly assigned them to aerobic or a combined aerobic/weight training groupsthe group the combined group reduced A1c by 1.0% Why does exercise help improve glycemic control? Effects of exercise on cancer reduction and recovery Improves insulin sensitivity via an increase in translocation of insulin-responsive glucose transporters (GLUT4) from intracellular stores to the cell surface-glut4 promotes glucose uptake which increases insulin sensitivity Meta-analysis (2012) of 21 studies examining prevention of colon cancer There was a 27% lower rate of cancer among the most physically active Meta-analysis (2009) of 52 studies of prevention of colon cancer There was an inverse relationship between physical activity and colon cancer Cancer reduction and treatment cont. Cancer reduction and treatment cont. Breast cancer risk reduction A review done by Friedenreich (2010) examined 73 studies that demonstrated evidence that physical activity reduced the incidence of breast cancer The average risk reduction was 25% when comparing the most active to the least active women Activity that is sustained over a lifetime had the greatest benefit however there was benefit when starting later in life Physical activity reduced breast CA risk in all but obese women A meta-analysis Zhong et al. (2014) examined the association between physical activity and mortality in breast cancer 16 cohort studies involving 42,602 patients Summary from the studies indicated that both prediagnosis and postdiagnosis physical activity were associated with reduced breast cancer-specific mortality and all-cause mortality 3

4 Cancer reduction and treatment cont. Why does exercise help reduce the risk of developing breast cancer? There is evidence that exercise reduces endogenous estrogen levels, insulin resistance, inflammation and adiposity Why does exercise help reduce the mortality risk? It again is postulated that exercise reduces insulin resistance thus lowering insulin levels through which breast cancer prognosis may be mediated; reduces inflammation and lower exogenous estrogen What are the risks associated with exercising? Musculoskeletal injury (most common) Arrythmia-increased risk in patients with underlying heart disease or prior history of dysrhythmias Sudden cardiac death In Physicians Health study-1.51 per 1.51 million episodes of exercise In Nurses Health study-1 per 36.5 million hours of exertion May not be increased with habitual exercise Risks associated with exercise cont. Myocardial infarction-physical or sexual activity is associated with a temporary increase in risk In study of 1194 patients who completed a survey within 2 weeks of having MI-7.1 % reported physical exertion prior to the onset The risk was much higher in patients who were inactive Risks associated with exercise cont. Medical evaluation prior to exercise Rhadbomyolysis More likely with endurance (marathon), extreme heat, electrolyte abnormalities (excessive sweating) Brochocontstriction Exercise-induced bronchoconstriction most likely to occur in patients with asthma diagnosis Hyperthermia Hypothermia Dehydration Caution of resistance training in patients with proliferative diabetic retinopathy To determine who needs further testing prior to an exercise program consider the following: Age General physical condition Exercise history Orthopedic history and musculoskeletal risks Medications (eg, beta blockers, calcium channel blockers, digoxin, nitrates, sulfonylureas and insulin) History of pulmonary disease Anticipated type of exercise Handicaps or disabilities 4

5 Guidelines for prescribing exercise programs Cardiorespiratory training Physical Activity guidelines from the American College of Sports Medicine (2011) Recommend a program that regularly includes cardiorespiratory, resistance, flexibility and neuromotor training Based on scientific evidence of indisputable benefits of physical activity These are designed to train beyond activities of daily living Adults engage in moderate-intensity cardio training for >30 min/day for >5 days/wk for total of 150 minutes of training OR Adults engage in vigorous-intensity cardio training for >20 min/day for >3 days/wk for a total of 75 minutes of training OR A combination of moderate and vigorous training to achieve a total energy expenditure of > MET/min/wk 5

6 Resistance training Flexibility exercise Adults should also perform resistance training 2-3 days a week These should focus on each strengthening the major muscle groups 8-12 repetitions is recommended improve strength and power- 2-4 sets are recommended 48 hours rest between sessions is recommended Gradual progression of greater resistance, repetitions or frequency is recommended 2-3 days a week is effective in improving joint range of motion with greatest gains occurring with daily exercises Stretch to the point of feeling tight Hold the stretch for seconds Stretches should include the major muscle-tendon units Flexibility exercises are most effective when muscles are warmed through light-moderate activity Neuromotor training How to write an exercise prescription? 2-3 days a week is recommended Should be done for minutes a day These exercises include motor skills ( balance, agility, coordination and gait) The effectiveness of neuromuscular training in younger and middle-age has not been established however it has been proven to help reduce and maintain function and reduce falls in older persons There is no one exercise prescription for all individuals A goal of 150 minutes of moderate intensity or 75 minutes of vigorous intensity activity (shorter goal for inactive participants to start) A prescription should include cardiorespiratory, resistance training, flexibility and neuromotor training Need to consider activities that the patient is likely to enjoy and are realistic for their lifestyle How to write exercise prescription cont. Individual should perceive a net health benefit The activity should be enjoyable (if possible) and the person should feel safe and competent The activity should be accessible on a regular basis and should fit easily into the patient s schedule The activity should not generate unbearable financial costs Try to garner support from family members-increases adherence Discuss the importance of role modeling-childhood activity is a predictor for adult activity Exercise prescription Wanna B. Fit Walking briskly for 10 minutes twice/daily 5 days/wk After one week increase your walking 10 minutes a day until you reach 45 minutes of walking a day (may want to walk once a day) Wall push ups 10 reps/2 sets-increase to 15 reps/3 sets over 2 weeks (3 dys/wk) Squats 10 reps/ 2 sets-increase to 15 reps/sets over 2 weeks (3 dys/wk) add weight if able-canned goods/milk 6

7 Effectiveness of exercise counseling A 2012 review of randomized trials of primary care promotion of physical activity over 12 months found a small to medium positive effect The United States Preventive Services Task Force reviewed trials of counseling for exercise and/or dietary change and found that moderate to intense counseling was associated with improvements in secondary outcomes (weight, blood pressure, lipids) and self reported physical activity level What about high intensity interval training? High intensity interval training or (HIIT) is a program that incorporates periods of intense work with periods of recovery (boot camps, Tabata, Insanity) The work intervals are short lasting from a few seconds to several minutes (up to 90% maximal VO2) The work is followed by rest periods which are active recovery lasting a few seconds to several minutes ( 40-50% VO2 max) High Intensity Interval Exercise cont. The maximal oxygen consumption (VO2 max), distribution and utilization increased up to 46% in training up to 24 weeks The resting heart rate was significantly lowered Stroke volume increased 10% in HIIT training 3x/wk for 8 weeks HIIT increased catecholamine response- epinephrine and norepinephrine- which is known to drive lipolysis. These hormones are largely responsible for fat release from both subcutaneous and intramuscular fat stores High Intensity Interval Training cont. High Intensity Interval Training cont. The recovery of muscles after HIIT training is biphasicinitially recovery lasts 10 sec to a few minutes-this is followed by a second, longer recovery phase lasting minutes to hours The second recovery phase is termed- excess post oxygen consumption (EPOC) EPOC is important because it requires additional energy which in turn increases the calorie expenditure of the individual after the workout Chronic responses to HIIT training include increased aerobic and anerobic fitness, skeletal muscle adaptations, improvement in insulin resistance, fat loss Trapp studied participants in a HIIT program for 15 weeks. 1 st group-20 minutes/3 x/wk-stationary bike- 8 second sprint followed by 12 second low intensity cycling 2 nd group cycled at steady state-60% VO2 max for 40 minutes Results: The HIIT group lost 2.5kg and the steady state did not lose weight 7

8 High Intensity Interval Training cont. High Intensity Interval Training cont. Mourier et al. studied type 2 diabetic men and women in a combination HIIT/steady state program They did steady state exercise 2 days/wk and HIIT 1 day/wk There was a 48% reduction in visceral fat measured by MRI There was an 18% decrease in subcutaneous fat Dunn studied a HIIT protocol with a Mediterranean diet for 12 weeks in overweight young women There was a 2.6 kg reduction in subcutaneous fat A 36% increase in insulin sensitivity HIIT has been studied in special populations like overweight adolescents, older adults, type I and II diabetics, paraplegics, intermittent claudication, chronic obstructive pulmonary disease, and cardiac rehabilitation patients It has been found to be effective and safe in these populations 8