Module 2 Study Guide PDF

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NUTR1023 Health and Fitness Through Diet and Exercise Semester One 2018 Module 2 – Physical Activity and Health Objectives At the end of this module students will be able to do the following:  

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Describe risk factors for lifestyle-related diseases, identifying which are primary, secondary, modifiable and non-modifiable. Describe evidence supporting the roles for exercise and physical activity participation in the prevention of lifestyle-related diseases such as cardiovascular disease, cancer and diabetes. Describe the dose–response relationships for exercise and physical activity interventions on lifestyle-related outcomes. Describe the process of atherosclerosis, and possible mechanisms by which exercise may intervene in this process. Describe the specific effects of exercise and physical activity on risk factors for lifestyle-related diseases. Describe the research literature related to the role of exercise in the secondary prevention of disease and the control of blood pressure, blood glucose and insulin resistance. Explain the role of sedentary behaviour and physical activity in the aetiology, prevention and management of lifestyle-related chronic diseases.

Study Tasks 1. Watch the video ‘23 and 1/2 Hours’ by Mike Evans before completing the following activities:   

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How much does physical activity reduce pain and disability in those with knee arthritis? 47% How much does physical activity, with other lifestyle interventions, reduce the progression to diabetes in those at risk? 58% Describe the benefits of having high cardiorespiratory fitness. Increases lifespan, decreases risk of diabetes, protects against cardiovascular disease, increase bone density, reduce blood pressure Explain the amount of exercise required to achieve health benefits. 150min of moderate aerobic activity or 75min of vigorous activity a week Describe the health risks associated with prolonged sitting. Relationship between sitting and early mortality, sitting burns less fat and blood doesn’t’ flow as smoothly. The longer you sit, the higher the risks of early mortality

2. Watch the videos ‘Physical Activity and Health’ and ‘Physical Activity and all-cause Mortality’ and then read chapter 2 ‘Physical Fitness and Health’ of the Porcari textbook before completing the following activities: 

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Define physical activity, exercise and physical fitness. Exercise - Any type of physical activity that involves planned, structured and repetitive movement. Usually with the intention of improving physical fitness. Physical activity –Any form of movement. Physical Fitness - The ability to meet the demands of daily life safely and effectively without undue fatigue. List the different methods used to measure exercise intensity. Heart rate, blood pressure, talk test, level of aerobic activity (running as opposed to walking) What are the limitations of using metabolic equivalents (METs) to measure exercise intensity? One major inconsistency in Table 11, which should be noted, is that some activities of relatively low intensity, such as bowling, bocce, and croquet are shown in the “heavy” intensity category with an intensity of 3 METS. Other activities, on the other hand, such as badminton, baseball, hiking, and folk dancing, are classified in the ‘‘light’’ intensity category also with an intensity of 3 METS. In Tables I and 11, activities classified as “heavy” range from a low of 3 METS to a high of 16 METS. Activities classified as ‘‘light’’ have a similar range of 3 to 12 METS. Therefore, these inconsistencies make the METs system flawed because several activities are mislabelled and therefore inaccurate List the different domains of physical activity. Active transport, household (domestic), exercise/leisure, occupational Explain the difference between primary and secondary prevention. Primary prevention is all measures taken before early diagnosis is possible. This is keeping the environment generally healthy and safe, staying personally healthy etc. A common form of this is immunisations, which are given as a precaution to develop immunity in a community (the immunisation isn't given after early diagnosis). Secondary prevention is after early diagnosis. This is the stage where treatment of early symptoms takes place. This is where most diseases and conditions can be fully repaired. Tertiary prevention is maximising comfort for the individual and minimising the symptomatic impact of the disease or condition they have. This is for conditions and diseases that are not treatable.

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Differences between the 3 types of intervention include the aim of each type of intervention: to prevent the disease before it starts, to to reduce the impact of a disease or to lessen the impact of the disease that has occurred. The types of intervention also differ in term of the approaches/methods they use to fulfil their aim. Compare and contrast the health-related components of physical fitness and the skill-related physical fitness. Activities that will helps your body keep

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healthy, including muscular strength, muscular endurance, cardiovascular endurance, flexibility, speed, power and body composition. Skilled- related physical fitness: help improve your body's ability to perform complex movements in everyday life, as well as in athletic and sports related activities, including agility, balance, co-ordination and reaction time.  Explain the curvilinear relationship between physical activity and health. People who enjoy regular physical activity have lower death rates than people who have no risk factors but who aren't physically active.  Explain what was found in the early studies of London bus drivers and conductors in the 1950s. Bus drivers, who sit on their seat and drive for most of the day were at a higher risk of a heart attack than Conductors who were on their feet and moving for most of the day. People that work physically active jobs have less coronary heart disease than those in physically inactive occupations. They also have an average of 4 years of extended life.  What types of studies are mostly used as evidence for the health benefits of physical activity? Describe the strengths and limitations of these types of studies. Epidemiological (cohort and case-control): Cohort pro - Large test group, cohort followed over time to measure development. Provide best information about causation of disease Cohort con – Study is very time consuming, takes a long period Case-control pro – Cheaper and do not require a follow up, useful for rare diseases. Case-control con – less adept at showing a causal relationship, more prone to bias

3. Watch the video ‘Physical Activity and Cardiovascular Disease’ and then read pages 14-16 of the Physical Activity Guidelines Evidence Report before completing the following activities: What types of studies are mostly used as evidence for the benefit of physical activity in reducing the risk of cardiovascular disease? Describe the strengths and limitations of these types of studies.  List the biological mechanisms through which physical activity is likely to cause a reduction in the risk of cardiovascular disease. - Atherosclerosis – A build up of plaque on the inside of blood vessels. - Improving red blood cell count - Increased heart capacity and strength combined with a low resting heart rate puts less stress on the heart to function. Increases lungs ability to take in and use oxygen. Increases Capacity to vasodilate, to let blood vessels and release nutrients. 

With increased physical activity: the heart becomes stronger and therefore for has a larger stroke volume (resting decreases), our muscles become more efficient at consuming oxygen, mitochondria (inside the muscle) increase in number and activity. 

Explain how the risk of cardiovascular disease changes with increasing amounts of physical activity. Physical activity demands an increase in oxygen uptake and blood

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distribution, which over time increases stroke volume, decreases systemic vascular resistance, relaxes the arteries etc. all of which contribute to a decreased risk of CVD. Therefore, the more physical activity, the more of these improvements and less risk of developing CVD. Increase in exercise tolerance Reduction in body weight Reduction in blood pressure Reduction in bad (LDL and total) cholesterol Increase in good (HDL) cholesterol Increase in insulin sensitivity

4. Watch the video ‘Physical Activity and Diabetes’ and then read pages 17-20 of the Physical Activity Guidelines Evidence Report and the Diabetes Prevention study by Knowler et al (2002) before completing the following activities:  

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What types of studies show a benefit of physical activity in reducing the risk of developing type 2 diabetes? Comment on the strength of this evidence. How much is the risk of diabetes reduced by regular physical activity? Is there a dose-response relationship between physical activity and a reduced risk of developing type 2 diabetes? Describe the effects of physical activity in the primary, secondary and tertiary prevention of diabetes. Which do you think is most important? Of all the stages of prevention for diabetes, primary is the most important. This is the easiest, and if done properly, the most general form of prevention. For example, if everyone on the planet remained fit and kept a good diet, there would be almost no cases of type 2 diabetes. Once prevention enters the second stage, the individual would have to be given a diet and exercise regime, which may be very difficult to follow, depending on their past experiences. Tertiary prevention is the least desirable, as when the individual reaches this stage, the sole intent would be to maximise their comfort. This could mean regular physio or hospital visits to aid in maintaining joint ROM and functionality, and to minimise muscle atrophy due to lack of activity. Can resistance training be an effective type of exercise for people with type 2 diabetes? There is now suggestive evidence supporting the use of resistance training for improving glycemic control and insulin sensitivity in type 2 diabetes. However this research is incomplete and should be looked into more to see if the effects can be more pronounced The Diabetes Prevention study by Knowler et al (2002) is considered to be a seminal paper in nutrition and exercise science. Explain why this study might be considered to be so influential. It determined the long-term extent of beneficial effects of lifestyle intervention on diabetes prevention. The lifestyle intervention significantly reduce diabetes development over 15 years. There were no overall differences in the aggregate outcomes. Describe the lifestyle modification program used in the Diabetes Prevention study by Knowler et al (2002). Minimum of 7% weight loss/weight maintenance and a minimum of 150 min of physical activity similar in intensity to brisk walking

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Do you think it would be feasible and practical to implement a lifestyle program similar to the one used in the Diabetes Prevention study by Knowler et al (2002) here in Australia? Explain your answer. Yes this lifestyle programme would be beneficial in Australia because it was successful in the US and diabetes is a significant issue in Australia - 6 billion was spent in the last year on type 2 diabetes. Describe how well participants in the Diabetes Prevention study by Knowler et al (2002) adhered to the lifestyle modification program intervention. Fifty percent of the participants in the lifestyle-intervention group had achieved the goal of weight loss of 7 percent or more by the end of the curriculum (at 24 weeks). The proportion of participants who met the goal of at least 150 minutes of physical activity per week (assessed on the basis of logs kept by the participants) was 74 percent at the end of the curriculum.

5. Watch the video ‘Physical Activity and Cancer’ and then read pages 21-26 of the Physical Activity Guidelines Evidence Report before completing the following activities: 

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The association between physical activity and the risk of developing cancer is strongest for which types of cancer? The strongest evidence suggests that physical activity can reduce the risk of breast cancer (ranging from 20%-40%) and the risk of colon cancer by 30%. Describe the benefits of physical activity for individuals who have been diagnosed with breast or colon cancer. reduction in symptoms, reduction in cancer, boost immune function, offset negative effects of treatment, at least 18 met hours/week. Improves immune system function which leads to greater white blood count to fight cancerous cells = homeostasis. Moderate exercise e.g. walking 3 to 5 hours per week at an average pace) after a breast cancer diagnosis had approximately 40% to 50% lower risks of breast cancer recurrence. What physiological mechanisms are most likely to be responsible for physical activity being able to reduce the risk of developing cancer? Physical activity has multiple physiological benefits on the body, some of which have been exemplified to explain the relationship between physical activity and specific cancers. These included: - A lowering of the levels of hormones, such as insulin, estrogen and certain growth factors (associated with development and progression of cancers) - A reduced risk of obesity and the harmful effects, particularly the development of insulin resistance (failure of the body's cells response to insulin) - Reduce inflammation - Increase function of the immune system - Altering the metabolism of bile acids, resulting in decreased exposure of the gastrointestinal tract to suspected carcinogens - Reducing the amount of time it takes to digest food, which coincides with exposure to possible carcinogens

6. Watch the video ‘Physical Activity and Sedentary Behaviour’ and then read pages 6269 of the Physical Activity Guidelines Evidence Report before completing the following activities: 

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Explain the association between occupational/leisure time sitting and the risk of early death from all causes, the risk of cardiovascular disease, diabetes and cancer. Risk early death from all causes lower for those highly active compared to least active. dose response - increased risk of death as time sitting increased, similar for CVD, no relationship with cancer. Sitting >30mins 45% increased chance death. Sit 13 hours 200% more at risk than those sit 11 hours a day Impact on lipid profile increasing risk of CVD - decrease in lipoprotein lipase resulting in increases in TGs, decreases in HDL Increases metabolic syndrome I.e. increased blood pressure, blood sugar, excess fat around the girth, elevated cholesterol 3 systematic reviews in the past 3 years Sedentary behaviour associated with higher risk of all cause mortality, Mixed moderate evidence suggest relationship with diabetes Insufficient evidence to associated with CVD, cancer Describe the key limitations of the body of evidence that examines the association between sedentary behaviours and health outcomes. One of the major limitations identified was that the relationship between SB and health outcomes could be influenced by occupational, leisure time or total physical activity. In the van Uffelen reviews, only 22 out of the 43 studies adjusted their results to include physical activity and exercise with 12 showing significant associations with SB and health outcomes and 10 did not. Another limitation was the complexity deciphering the direction of any relationship. There is a possibility that BMI or weight gain could be mediators of the relationship between SB and health outcomes. Additionally, weight gain and SB may be mutually reinforcing as increase weight gain leads to more SB and more SB leads to an increase in weight gain. How much TV/screen time each day is associated with an increased risk of early death from all causes? Studies suggest that adults who spend >4 hours of TV/ screen time per day are at an increased risk from all causes by 50% - Scottish Health and AusDiab. Meta analysis indicated increased risk >3 hours per day. Consensus more than 8 hours/day increased risk. 6 hours a day decreases person life by up to 5 years.

7. In the table below, list what you think are the 10 most important benefits of physical activity in order of importance from highest to lowest. Include the reasons for your

ranking (hint: there are no right or wrong answers, but you need a good reason for ranking certain benefits as more important than others) Rank 1

Benefit of Physical Activity Health

2

Mental health

3

Energy

4

Brain Function

5

Decreased risk of disease

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Live longer

7

Fitness

8

Feel good

9

Sleep better

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Obesity reduction

Reason for Ranking

8. The table below lists some of the common barriers that individuals report when asked why they do not participate in sufficient physical activity. List some specific strategies that could be used to overcome each of the barriers. Barrier Lack of time

Strategies - Get an app to manage your time - Make detailed plan of every day - Prioritise your time, plan out a schedule

No support from family or friends

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Join a gym and make new friends that share your interests

Lack of motivation

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Find something that you enjoy Watch health documentaries on how physical activity is beneficial to overall health

Don’t enjoy exercise

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Find a hobby/sport that you enjoy Play a social sport with friends

Fear of injury

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Get a spotter Stretch Low to high intensity Correct method to avoid injury Guidance from PT Start with basics and work your way up

Poor access to facilities

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Utilise stuff at home Exercises that don’t need equipment

Family and social obligations

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Make your hobby part of your weekly routine Tie it in with obligations (involvement)

Lack of confidence...