Summary Of Hms Physical Activity And Health PDF

Summary HMS Physical activity and health Tutorial group cases What is energy expenditure? How is it calculated by a accelerometer and what influences the METs? Energy expenditure is the energy someone needs in 24 hours to maintain basic body functions and to do their physical activity. Energy expen...

Summary HMS Physical activity and health Tutorial group cases What is energy expenditure? How is it calculated by a accelerometer and what influences the METs? Energy expenditure is the energy someone needs in 24 hours to maintain basic body functions and to do their physical activity. Energy expenditure contains the following: - Basic metabolic rate (BMR): energy expended while resting with an inactive digestive system. So, the energy to maintain vital body functions (breathing, circulation, cel production, temp regulation) - Thermic effect of food (TEF): energy needed to digest, absorb, matabolize and store nutrients from food. Different nutrients need different amounts of energy to process. Proteins cost the most energy. This process also generates heat - Physical activity: energy used to move the body (exercising, daily activities etc.) - Thermogenesis: energy you need to heat your body, this is devided into: o Non-exercise activity thermogenesis (NEAT): energy needed to maintain posture or do small movements o Adaptive thermogenesis: energy used to respond to changes in your environment (f.e. change in temperature) Energy expenditure is influenced by: - Age: lower metabolism - Sex: men have a higher BMR because of a higher muscle mass - Genetics - Hormonal levels: thyroid hormones play a big role in regulating metabolism - Environmental temp: exposure to heat or cold can increase energy expenditure because the body needs to work to maintain temperature MET stands for Metabolic Equivalent of Task, this represents energy expenditure while performing a specific activity compared to resting metabolic rate. 1 MET is the energy expended while resting. This is 3,5ml of O2 consumed per kg of bodyweight per minute. 3,5 ml/kg/min. METS are influenced by: - Fitness level: the fitter the less calories someone will burn - Age  - Gender - Body composition: more muscle mass is higher energy expenditure - Activity intensity: higher activity the higher the expenditure - Environment: temp, humidity and altitude influence energy expenditure Accelerometers measure acceleration in one or more directions. They come from movement, vibration or changes in orientation. They are triaxial and measure acceleration in a vertical, horizontal and lateral axis. The change in velocity over time are converted into electrical signals which are processed to determine the intensity, frequency and duration of the movement. The movement of the different axes are combined. Then the intensity, pattern and type of movement are identified. Then the algorithm makes a MET-score out of data. The personal data (sex, age, weight, height etc.) is also incorporated to redefine the MET-score. With the MET-score you can calculate energy expenditure. Energy expenditure= MET x bodyweight (kg) x duration (hours) How do different wearables differ from each other and how do they work? They use a lot of different sensors. These are the most used sensors: - Accelerometer: measuring velocity to track steps, movement patterns and exercise intensity. - Gyroscope: detects rotational movements to recognize activities. - Heart rate monitor: measures heart rate by using photoplethysmography (PPG) which uses light to detect blood flow under the skin. It sends out light which is reflected by the blood so it can measure differences and detect a heart rate out of it. - GPS: tracks location, distance, pace during outdoor activities - Barometer: detects changes in elevation - Optical sensors: measures sleep patterns and sometimes also saturation Indirect calorimetry vs doubly labeled water Indirect calorimetry estimates energy expenditure based on consumed oxygen (VO2) and produced carbon dioxide (VCO2). This is considered as the golden standard for measuring resting metabolic rate (RMR) and total energy expenditure (TEE). It can also give you an insight in substrate use, you can differ between carbs and fat using the RER rate (difference in VO2 and VCO2). The test is expensive because only trained personel can conduct it. It is conducted in a controlled environment so you can’t use it in specific conditions. Doubly labeled water is used to get an accurate insight in the energy expenditure over a longer period (one to two weeks). You give the patient water which is labeled with stable isotopes of hydrogen and oxygen. Over time the hydrogen is lost via water. The oxygen is lost via water and carbon dioxide. During and after the time samples (blood, saliva or urine) are collected to measure the concentration of the isotopes. The difference in the number of isotopes is used to calculate the VCO2 to estimate the energy expenditure. The doubly labeled water is used to measure energy expenditure in real life settings. You can also evaluate the energy that a special diet or lifestyle costs. It provides precise measurements of energy expenditure, and it is non-invase on patients and can be used long term (a minimum of 3 days). On the other hand, it is really expensive and limitedly available. Why do different people get different outcomes with the same wearable? - Different resting energy - Difference in fitness level - Darker skin tone: absorbs more light which can cause inaccurate heart rate reading - Heart rate variability: people with higher fitness have a lower variability in heart rate. - Diseases: COPDà lower physical activity and lower muscle mass Lectures Physical activity is defined as bodily movement produced by skeletal muscles that require energy expenditure. Movement is also called displacement. MOX is designed by Maastricht instruments and measures accelerations in 3 directions. It has a range of +/- 8G. The sample rate is 25 Hz. Normally it is worn on the thigh or placed in the pocket. The MOX classifies in posture and motion. Posture contains laying, sitting and standing Motion contains walking, running, cycling, non-level walking (stairs or uphill) etc. You have different gait parameters: - Amount of steps - Step frequency - Walking speed - Step length - Stride length - Step asymmetry When you want to validate something, you need to look at the sensitivity and specificity. Sensitivity is the ability to correctly identify the condition. Specificity is the ability to correctly identify as not the condition Sensitivity= true positives / true positives + false negatives Specificity= true negatives / true negatives + false positives Movement is displacement which is measurable by wearables which measure accelerations. Physical activity is the accelerations translated to energy expenditure Energy expenditure= basal metabolic rate+ thermic effect of food+ energy expended in physical activity. Energy expenditure is measured as oxygen consumption (VO2) in a indirect calorimetry. Energy expenditure is related to task difficulty (gait speed etc.) but also influenced by factors like age, body composition and disease. 1 MET= basal metabolic rate (approximately 3,5 ml O2 per kg of bodyweight per minute= 3,5 ml/kg/min HOW TO INTERPRET BLAND-ALTMAN PLOTS????? PICO question: Population, Intervention, Comparison, Outcome Controlled setting: to check if you can measure what you want to measure Free living setting: measurements in real life We can measure different signals in the human body. For example: - Physical signs o Pressure o Motion o Tactile o Vibration - Thermal signs o Fever o Hypothermy - Electrophysiological signals o Brain waves o Cardiac activity o Muscle movement EMG (electromyography) uses a electrode on the skin which can measure the activity of the alpha motoneurons which send a signal to the muscle to activate. This electrode measures individual motor unit action potential trains (MUAPTs) and combines them to a raw EMG signal. Sit less for health You have different types of people when it comes to physical activity. - Active occupation: people who have an active job and then do nothing for the rest of the day - Guideliner: people who perfectly fit the guidelines - Opportunity taker: people who try to get as much daily activity as possible - Weekend warrior: people who do nothing during the week and get as much activity as possible at the weekend. Research outcomes of the lecture - Bus conductors are healthier than bus drivers - Ice skaters live longer than people who don’t do it (might be fully inactive) - Sitting increases mortality The Maastricht study - 10000 participants, 1/3 with DM2 - 40-75 years old - 4x4 hours visit at the research center - Advanced phenotyping - Thematic multidisciplinary research team o Chronic diseases: diabetes, CVD, respiratory disease o Cardiovascular: CT, ultrasound, BP, ECG and PWV o Central nervous system: cognition, brain MRI and neuropathy o Public health: SES, social networks o Biomarkers: OGTT, lipid profile and inflammation o Lifestyle: diet and physical activity PA and metabolism and energy expenditure Concept of energy balance Thermodynamics is the conservation of energy. Energy can be transformed (changed from one form to another) but cannot be created or destroyed. Increase in internal energy of a system is equal to the amount of energy added minus the amount lost as a result of the work done. Components of energy expenditure Enrichment of the hydrogen-2 isotope after injecting it in the body. Enrichment of the oxygen-18 isotope after injecting it PAL (physical activity level)= TEE (total energy expenditure)/ BMR (body metabolism rate?) PAL of - Cycling: 4.4 - Soccer: 1.7-1.8 - Triatlon: 3.8 - Ultramarathon: 3.2 - Crossing the Atlantic: 6.3 - 11 city swim: 6.4 Main determinant of energy expenditure is body mass/ body composition. Increasing physical activity can increase energy expenditure but compensatory mechanism may occur to limit total energy expenditure. Short term energy expenditure can be as high as 40x BMR. Long term maximal PAL levels out at +/- 2,5x BMR PA and cardiovascular health Cardiovascular diseases are the main cause of death in the world. Mainly ischemic and cerebrovascular diseases. Thomas Edison said that in the future doctors will cure and prevent disease with lifestyle and nutrition. Improving diet and lifestyle is a critical component of the American heart association to prevent for cardiovascular diseases. Maintaining a healthy diet and lifestyle has the greatest potential to reduce the risk of cardiovascular diseases. Physical activity decreases the risk of cardiovascular diseases The following things have an influence on vascular and so cardiovascular health: - Inflammatory profile: low profile is good for vascular health - Blood pressure: low blood pressure is good - Physical (in)activity: active is good for vascular health - Serum lipids: low is good for vascular health - Insulin sensitivity: high is good for vascular health If you are inactive the opposite happens of the above. Vascular health is determined by vascular function, microvascular structure and arterial stiffness To assess the quality of your blood vessels you firstly check the endothelial function, then the arterial stiffness. Vascular function is measured in the brachial artery, stiffness is measured in the aorta Vascular function is measured by flow-mediated dilation with ultrasound because it is safe to use. You look at the increasement of the vascular wall during blood flow. The blood flow will be decreased with a bp pressure cuff, the nitric oxide will decrease as well, and the arterial wall will contract. The wall will dilate when the cuff gets loose. People who are physically active increase their vascular function. This can reduce the risk of cardiovascular diseases by 22%. Vascular stiffness is measured by pulse wave velocity. It uses 2 probes which are placed on the carotid and femoral artery. This is used to measure the speed of blood flow. Arteries need to work as a balloon to slow the blood down. The speed of the flow is determined by the stiffness of the arteries. Normal blood flow is 30-40 km/h, the stiffer the blood vessel the higher the speed of the blood flow. So, during the measurement you want to see the blood flow slowing down. People who are physically active can decrease the stiffness of their blood vessels; this can decrease the risk of cardiovascular diseases by 9%. In the future Alzheimer and dementias will be the problem. This will become the world’s highest death cause. Mainly because low and middle income countries are not on track of preventing dementia and because their population will grow older so dementia will occur more often. This is why the vascular health of the brain is a hot topic in research. Because a problem in the vascular health of the brain can lead to cognitive impairment. Microvascular structure is a good indicator of brain vascular health. This is done by retinal images. Of course, MRI is the golden standard, but this is really expensive which makes retinal images a good alternative measurement technique. With an MRI scan you can look at cerebral perfusion. If this perfusion decreases, there is a problem with the vascular health of your brain. When people become more active the vascular health in your brain… The first study used the following design: The main outcomes of the study were glucose metabolism, cerebral perfusion and perceivable cognitive benefits. The following parameters were secondary outcomes: - Physiological parameters o Glucose metabolism: tested by oral glucose tolerance test o Vascular function: tested by peripheral vascular function markers  o Cardiometabolic risk markers: f.e. blood pressure, lipid levels, glucose tolerance and inflammation markers - Perceivable benefits o Cognitive functioning: tested by a neurophysiological test battery o General well-being: quality of life, sleep charecteristics and mood o Physical fitness: strength, speed and endurance o Endothelial function: flow-mediated vasodilation o Arterial stiffness: pulse wave velocity o Vascular structure: intima-media thickness o Microvascular function: retinal microvascular images o Wearables: blood pressure, glucose levels and energy expenditure On an MRI you can also see the loss of brain mass when we age like the image below. In brain research there is nowadays a big focus on the anterior cingulate cortex, the fusiform cortex and the subcallosal cortex.