Sept 12 students.pdf

HES 383 – PHYSICAL DIMENSIONS OF AGING Sept 12, 2023 General Functional decline & Changes in Body Composition Prof Gina Whitaker, BSc Kin, PhD The UBC Okanagan Campus and the City of Kelowna are located on the traditional, ancestral, and unceded territory of the Syilx Okanagan Nation. PRIMARY VS...

HES 383 – PHYSICAL DIMENSIONS OF AGING Sept 12, 2023 General Functional decline & Changes in Body Composition Prof Gina Whitaker, BSc Kin, PhD The UBC Okanagan Campus and the City of Kelowna are located on the traditional, ancestral, and unceded territory of the Syilx Okanagan Nation. PRIMARY VS SECONDARY AGING OF THE BODY • Primary Aging – unavoidable deterioration of structure and function • This is independent of disease and environment • Secondary Aging – deterioration of structure and function due to preventable lifestyle and environmental exposures • Usually seen in the context of disuse that occurs with aging e.g. increased inactivity and sedentary behaviour • Can be modified through intervention A DECLINE IN FUNCTIONAL CAPACITY WITH AGE • We start with a max capacity (determined by genetics + environment during development) • The rate of decline varies from organ-toorgan and person-to-person • Reduced reserve capacity means the organ is more vulnerable to stresses placed on the body and has a greater risk of succumbing to those stresses Figure 1 Changes in bone, muscle and fat tissues with increasing age (indicating some typical events), and accompanying increase in low-grade chronic inflammation. JefariNasabia P, et.al. (2017). Aging human body: changes in bone, muscle and body fat with consequent changes in nutrient intake. Journal of Endocrinology 234(1):R37-51 DECLINE IN BONE MASS WITH AGING • The peak bone mass we achieve will dictate our reserve capacity as we age • Bone mineral density starts to decline more measurable at around 50 YO • Bone resorption > Bone formation • Depends on • Sex (hormones) • women can lose up to 20% of bone mass during the 5-7 years post-menopause, then 0.5-1% per year • Men lose bone too, but without the hormonerelated acceleration. Steady at around 0.5 -1% per year • Genetics, nutrition, PA level, comorbidities • Fat can also infiltrate bone (linked to disuse / sedentary patterns) and this contributes to weaker bones Weaver, C.M., Gordon, C.M., Janz, K.F. et al. The National Osteoporosis Foundation’s position statement on peak bone mass development and lifestyle factors: a systematic review and implementation recommendations. Osteoporos Int 27, 1281–1386 (2016). https://doi.org/10.1007/s00198-015-3440-3 Figure 1 Changes in bone, muscle and fat tissues with increasing age (indicating some typical events), and accompanying increase in low-grade chronic inflammation. DECLINE IN MUSCLE MASS & STRENGTH WITH AGING • Muscle Mass peaks at ~30YO, followed by gradual decline of 3-8% per decade, increasing after 65YO • 20-40% loss by 70YO • Rate of decline largely determined by diet and physical activity level • Fat infiltrates muscle (myosteatosis) • Can lead to Sarcopenia Clinical loss of skeletal muscle mass and strength Sayer AA, et al. (2013) New horizons in the pathogenesis, diagnosis and management of sarcopenia. Age Ageing 42(2) 145-150 VARIABILITY IN MUSCLE DECLINE AS A FUNCTION OF EXERCISE FIGURE 3.MRIs taken across the mid region of the thigh Images taken across the mid region of the thigh, showing a sarcopenic muscle (middle) from a sedentary individual with reduced contractile mass, more subcutaneous fat, and infiltration of fat and connective tissue. By contrast, the muscles of a similarly aged master triathlete (bottom) shows little difference to that of a younger athlete (top). From: Harridge S.D.R & Lazarus, N.R. (2017) Physical Activity, Aging and Physiological Function. Physiology 32(2): 152-161 Figure 1 Changes in bone, muscle and fat tissues with increasing age (indicating some typical events), and accompanying increase in low-grade chronic inflammation. FAT MASS & DISTRIBUTION WITH AGING • % body fat and total fat mass increases with age • Increased subcutaneous & visceral fat • Increased fat mass in abdominal (android) region • Correlates to visceral fat • Associated with increased risk of metabolic disorders and CV disease • Infiltration of fat into muscle tissue and bone Dual-Energy X-Ray Absorptiometry (DXA) examination of body composition Old Male Old Female Young Female Young Male Ponti, F., et. al. (2020). Aging and Imaging Assessment of Body Composition: From Fat to Facts. Frontiers in endocrinology, 10, 861. CT image (transverse section) of the android region Young Male Old Male Young Female Old Female Arrowheads are pointing to the visceral fat Arrows are pointing to subcutaneous fat Ponti, F., et. al. (2020). Aging and Imaging Assessment of Body Composition: From Fat to Facts. Frontiers in endocrinology, 10, 861. CHANGE IN BODY WEIGHT WITH AGING • Average increase in body weight by up to ~15% between 25 – 60YO • Due to increase in fat mass • Concomitant 3-5% decreases in resting metabolic rate per decade • Decreased fat free mass • Lifestyle changes Frenzel, A., Binder, H., Walter, N. et al. The aging human body shape. npj Aging Mech Dis 6, 5 (2020). https://doi.org/10.1038/s41514-020-0043-9 CHANGES IN BODY HEIGHT WITH AGING CHANGES IN BODY COMPOSITION (USING TRADITIONAL MEASUREMENTS) Frenzel, A., Binder, H., Walter, N. et al. The aging human body shape. npj Aging Mech Dis 6, 5 (2020). https://doi.org/10.1038/s41514-020-0043-9 CHANGES IN TOTAL AND B ASAL ENERGY EXPENDITURE ACROSS THE LIFESPAN  Adjusted values to normalize for fat-free mass and fat-mass TEE = Total Energy Expenditure BEE = Basal Energy Expenditure Pontzer H, et. al.; IAEA DLW Database Consortium. Daily energy expenditure through the human life course. Science. 2021 Aug 13;373(6556):808812. doi: 10.1126/science.abe5017. PMID: 34385400; PMCID: PMC8370708. Figure 1 Changes in bone, muscle and fat tissues with increasing age (indicating some typical events), and accompanying increase in low-grade chronic inflammation. A VICIOUS TRIAD • The vicious cycle: Muscle and bone loss, and visceral fat accumulation with aging, combined with increase total adiposity  chronic inflammation  favors more muscle and bone breakdown and promotes obesity • The vicious triad: can lead to Osteosarcopenic Obesity Syndrome • A multimorbid state that predisposes an individual to morbidity Fig 2 • Increased risk of weakness and imbalance, falls, fractures, further decline in function, frailty, disease MEASUREMENT OF FUNCTIONAL DECLINE • DEXA Scan in order to get a picture of what is going on in terms of tissue distribution • Muscle and Fat amount and distribution • Bone Density • Fat infiltration within muscle • Functional tests • E.g. Short Physical Performance Battery (SPPB) protocol DEXA: Dual energy X-ray Absorptiometry SHORT PHYSICAL PERFORMANCE BATTERY (see full protocol posted in CANVAS) Consists of: • Balance Tests • Gait Speed Tests • Chair Stand Tests Good assessment for balance, mobility & lower body strength - A well-validated test - Strong associations with disability, hospitalisation and institutionalisation - Used in institutional and community-dwelling populations of older adults Figure 1 Changes in bone, muscle and fat tissues with increasing age (indicating some typical events), and accompanying increase in low-grade chronic inflammation. ACUTE VS. CHRONIC INFLAMMATION • Acute inflammation • High-grade • Essential for survival – how the body repairs itself • After a cut, sprain, bruise, or other trauma to the body, after exercise • Outcome: Healing, tissue repair • Chronic inflammation • Persistent, low-grade • Associated with ageing – chronic exposure to environmental stresses, metabolic dysfunction, damage build up • Detrimental to function • Outcome: further damage, increased disease risk • Promotes catabolic state: • Decreased mitochondrial function, Muscle atrophy, Bone breakdown, infiltration of fat within muscle and bone, Insulin resistance, etc. CAUSES AND CONSEQUENCES OF LOW-GRADE SYSTEMIC CHRONIC INFLAMMATION (SCI) Furman, D., Campisi, J., Verdin, E. et al. Chronic inflammation in the etiology of disease across the life span. Nat Med 25, 1822–1832 (2019). https://doi.org/10.1038/s41591-019-0675-0 CHRONIC INFLAMMATION IS A RISK FACTOR FOR MULTIPLE CHRONIC DISEASES Inflammageing: An agerelated chronic persistence of pro-inflammatory markers in blood - a strong risk factor for many diseases of ageing and a predictor of morbidity and multimorbidity Franceschi, C., Garagnani, P., Parini, P. et al. Inflammaging: a new immune–metabolic viewpoint for age-related diseases. Nat Rev Endocrinol 14, 576–590 (2018). https://doi.org/10.1038/s41574-018-0059-4