BMS6208: Sport Medicine - Physical Activity, Diet & Health

Introduction to Non-Communicable Diseases (NCDs)

Prevalence and Impact: * There is a rising prevalence of non-communicable diseases globally. * Key NCDs include cardiovascular disease (CVD), cancer, diabetes, and chronic respiratory disease. * In the UK, $89\%$ of deaths are attributed to chronic NCDs. * NCDs typically develop over many years and are strongly linked to behavioral and metabolic risk factors.
Modifiable Risk Factors: * Smoking. * Unhealthy diet. * Physical inactivity. * Harmful alcohol use. * Obesity. * High blood pressure (hypertension). * High cholesterol.
Interaction of Lifestyle Behaviors: * Diet and physical activity are not independent; they interact together to manage and prevent NCDs.

Lipid Metabolism and Lipoproteins

Cholesterol Overview: * It is an essential component of all cell membranes. * It serves as a precursor for bile acids (vital for digestion and absorption), steroid hormones, and vitamin D. * Sources of Cholesterol: * $20\%$ comes from dietary intake. * The remaining $80\%$ is synthesized endogenously by the body. * Synthesis occurs mainly in the liver, though most tissues possess the ability to produce it. * Pathology: Excess cholesterol can accumulate in blood vessels, leading to atherosclerosis (disruption or restriction of blood flow), which may result in angina, myocardial infarction (heart attack), or stroke. * Correlation: Low cholesterol levels are associated with low rates of Coronary Heart Disease (CHD); high cholesterol levels correlate with high CHD rates.
Triglycerides: * The major storage form of fats and dietary energy in the body.
Lipoproteins: * Lipoproteins are lipids (cholesterol, phospholipids, and triglycerides) of varying densities carried in the blood as globular complexes of lipids and proteins. * They are metabolically active, in constant flux, and interact with receptors and enzymes on cell surfaces. * Classifications: * LDL (Low-Density Lipoprotein): Often referred to as "bad" cholesterol. * VLDL (Very Low-Density Lipoprotein). * HDL (High-Density Lipoprotein): Often referred to as "good" cholesterol.
Clinical Biochemistry Testing: * A full lipid profile is required for the diagnosis and management of lipid disorders. * Components of the profile include: * Total cholesterol ( $mmol/L$ ). * HDL-C ( $mmol/L$ ). * LDL-C ( $mmol/L$ ). * Triglycerides ( $mmol/L$ ), ideally measured while fasting. * Note: Age and gender can impact test results.

Cardiovascular Risk and LDL Reduction

Risk Factors: Raised LDL cholesterol is a primary risk factor for CVD.
Impact of LDL Reduction: A $1\,mmol/L$ reduction in LDL-C is linked to: * A $12\%$ reduction in all-cause mortality. * A $19\%$ reduction in coronary mortality. * A $21\%$ reduction in major vascular events.
Predictive Limitations: While blood cholesterol concentration influences risk, it cannot predict individual risk in isolation. Other contributing variables include high saturated fat intake, smoking, hypertension, body weight, and physical inactivity.

Physical Activity: Definitions and Adaptations

WHO Definition (2024): "Any bodily movement produced by skeletal muscles that requires energy expenditure." * Includes movement during leisure time, transport (walking/cycling), work, or domestic activities.
General Health Effects: Both moderate and vigorous-intensity activity improve health. Conversely, physical inactivity increases the risk for NCDs.
Acute Adaptations (Immediate and Transient): * Cardiovascular: Increased heart rate ( $HR$ ), stroke volume ( $SV$ ), cardiac output ( $CO$ ), and blood pressure ( $BP$ ). * Respiratory: Increased tidal volume and breathing rate. * Muscular: Increased blood flow, nutrient uptake, and activation of metabolic pathways. * Metabolic: Increased glycogen breakdown and activation of energy systems (including lactic acid production).
Chronic Adaptations (Long-term and Structural): * These improve efficiency and performance but may reverse if training ceases. * Cardiovascular: Decreased resting heart rate, cardiac hypertrophy (increased heart volume), increased blood volume, and reduced blood pressure. * Muscular: Muscle fiber hypertrophy, increased capillary density, and increased mitochondrial density. * Respiratory: Enhanced efficiency of gas exchange. * Metabolic: Improved insulin sensitivity, better lactate threshold, and increased capacity to oxidize fat for fuel. * Structural: Increased ligament and tendon strength; increased bone density.
Health Interventions: Chronic adaptations are utilized in prevention and intervention programs for CV health, Type 2 Diabetes, weight management, and mental health.

WHO and UK Physical Activity Guidelines

General Principles: Every move counts; some activity is better than none.
Adults (18-64) and Older Adults (65+): * Aim for $150$ to $300$ minutes of moderate-intensity aerobic activity per week, OR $75$ to $150$ minutes of vigorous-intensity activity. * Muscle-strengthening activities should be performed on at least $2$ days a week.
Older Adults (Specific): Should include multicomponent activities emphasizing functional balance and strength training on at least $3$ days a week to prevent falls.
Children and Adolescents (5-17): At least $60$ minutes of moderate-to-vigorous intensity physical activity daily.
Pregnant and Postpartum Women: Aim for at least $150$ minutes of moderate-intensity aerobic activity per week.
Sedentary Behavior: Everyone should limit sedentary time and replace it with any intensity of physical activity.
UK Specific Note: Recommendations focus on $150$ minutes of moderate intensity per week, but acknowledge that physical activity alone has limited impact without dietary considerations.

Dietary Strategies for Health

Dyslipidaemia Treatment: Diet is a key component in managing lipid profiles and NCDs.
Fat and Fibre Recommendations: * Saturated Fat: Reduce intake and replace with unsaturated fats found in vegetable oils (olive, rapeseed, sunflower), nuts, seeds, avocado, and oily fish. * Fibre: High intake lowers heart disease risk. * Aim for $5$ portions of fruit and vegetables per day. * Choose wholegrain varieties of bread, cereal, pasta, and rice. * Consume pulses (lentils, beans, chickpeas), oats, and unsalted nuts/seeds. * Soluble Fibre: Specifically reduces LDL-C by binding to it during digestion, preventing absorption into the bloodstream.
Plant Stanols and Sterols: * These mimic cholesterol and inhibit its absorption in the gut. * Consuming $1.5\,g$ to $3\,g$ daily, alongside a healthy diet, can reduce cholesterol by $7\% - 12.5\%$ within $2 - 3$ weeks. * Available in fortified foods like mini drinks, spreads, milk, and yoghurts.
Dietary Cholesterol: Found in eggs, shellfish (prawns, crab), and offal (liver, kidney). These are low in saturated fat and are acceptable in a healthy diet; reducing saturated fat is more critical than limiting these specific foods.
The Mediterranean Diet: * Heart-healthy, plant-focused pattern aligned with the UK Eatwell Guide. * Emphasis on: Fruits, vegetables, wholegrains, beans, nuts, seeds, and olive oil. * Limitations: Red meat and processed foods are limited. * Proteins: Favors fish, poultry, and moderate dairy.

Interaction Effects and Synergy

Diet + Physical Activity: * Synergistic effects on insulin sensitivity and CVD risk reduction. * Prevention of sarcopenia: Exercise enhances nutrient partitioning. * Protein intake combined with resistance training maximizes muscle protein synthesis.
NCD Specific Management: * CVD: Combined lifestyle interventions are most effective. * Type 2 Diabetes: Lifestyle modification is the first-line management. * Obesity: Drivers are both behavioral and environmental.

Patient Assessment and Body Mass Index (BMI)

Comprehensive Patient Considerations: * Anthropometrics: Weight, BMI, Waist circumference (considering ethnicity). * Biochemistry: Full lipid profile, HbA1c, Blood Pressure. * Clinical History: Family history (PFHx), medications, new/chronic diagnoses. * Dietary Habits: Typical day patterns, nutritional literacy. * Environmental/Functional: Social factors, mobility, current activity levels.
BMI Classifications (General): * Healthy weight: $18.5\,kg/m^2$ to $24.9\,kg/m^2$ . * Overweight: $25\,kg/m^2$ to $29.9\,kg/m^2$ . * Obesity Class I: $30\,kg/m^2$ to $34.9\,kg/m^2$ . * Obesity Class II: $35\,kg/m^2$ to $39.9\,kg/m^2$ . * Obesity Class III: $40\,kg/m^2$ or more.
Ethnicity-Specific BMI Thresholds: * Individuals of South Asian, Chinese, other Asian, Middle Eastern, Black African, or African-Caribbean background are more prone to central adiposity. * Cardiometabolic risk occurs at lower BMI levels for these groups. * Adjusted Thresholds: * Overweight: $23\,kg/m^2$ to $27.4\,kg/m^2$ . * Obesity: $27.5\,kg/m^2$ or above.
Health Impact of Obesity in Wales: * High BMI is the leading risk factor for living with long-term illness. * Over $100,000$ cases of Type 2 Diabetes are associated with obesity. * Musculoskeletal (MSK) illness is $1.5\times$ more common in those with obesity. * Obesity is the second biggest preventable cause of cancer in the UK; more than $1$ in $20$ cancer cases are caused by excess weight.

Systems Mapping and Social Determinants

Complexity of Weight Regulation: It is more complex than simple "calories in vs. calories out."
Foresight Systems Map Clusters: * Biology: Genetics, satiety levels, resting metabolic rate. * Individual Psychology: Self-esteem, stress, food literacy. * Social Psychology: Media influence, social acceptability of fatness. * Food Production: Industry growth pressures, cost of ingredients. * Food Consumption: Nutritional quality, energy density, portion sizes. * Physical Activity Environment: Walkability, perceived danger, cost of exercise. * Individual Activity: Recreational and occupational activity patterns.
Inequalities: * Food deserts. * Socioeconomic status. * Access to recreational spaces. * Cultural dietary and activity patterns.

Public Health Policy: Healthy Weight - Healthy Wales

Strategy Goals (2019-2030): A long-term strategy by the Welsh Government to reduce obesity.
Priority Areas (By 2030): * Food Environment: Advertising restrictions, reformulation, and healthier retail options. * Active Environment: Active travel, safer communities, and green spaces. * Healthy Settings: Healthy childcare, schools, workplaces, and NHS settings. * Healthy People: Prevention during "The Best Start" (early years) and specialist treatment pathways.
Plan for 2025-2027 Themes: 1. Embedding a whole system approach. 2. Supporting families and foundations for lifelong health. 3. Schools and settings supporting good health. 4. Creating healthier food environments. 5. Active lives. 6. Treatment pathways.

Life Stages: Perimenopause and Menopause

Timing: Symptoms can start as early as age $35$ , but typically occur between $45 - 55$ .
Physiological Changes: * Irregular periods due to changing hormones. * Hidden changes: Increased blood pressure, increased cholesterol, and rapid loss of calcium/minerals from bones.
Symptoms: Weight gain (specifically around the waist), bloating, hot flushes, night sweats, insomnia, irritability, and joint pains.
Management Strategies: * Synergy: Combined healthy eating and exercise is most effective. * Resistance Training: Essential $2$ to $3$ times per week to prevent muscle loss. * Monitoring: Checking cholesterol and Vitamin D levels is recommended. * Diagnosis: Primarily based on symptoms despite falling oestrogen levels.

Future Directions in Sports Medicine

Personalised Nutrition: Tailoring diets based on individual biological data.
Biotechnology: Advances in blood testing and continuous monitoring.
Digital Health: Use of wearable technology for real-time tracking.
Microbiome research: Understanding gut health impact on NCDs.
Precision Exercise: Prescription of specific exercise types for individual physiological needs.
Ethical Question: Will these emerging technologies be accessible to all, or will they widen health inequalities?