| 1. |
- Montiel Rojas, Diego, 1984-
(författare)
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Diet and sarcopenia risk in community-dwelling older European adults
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The age-related decline in muscle strength and muscle mass can lead to sarcopenia with higher risk of falls, disability, and loss of independence. In this context, healthy dietary habits have the potential to delay onset of physical limitations, thereby promoting healthy ageing. The overall aim of the thesis was to investigate the role of dietary habits on indicators ofmuscle health in a sample of community-dwelling older European men and women. The studies were performed within the frame of the NU-AGE project, a multi-centre study aiming to determine the impact of dietary habits on age-related functional decline. Studies I-III were based on crosssectional analyses, whereas study IV was a randomised controlled trial (RCT). In summary, Study I highlighted the independent roles of dietary protein amount and quality for muscle health in older adults. A positive linear dose-response relationship existed between protein intake and muscle health, with increased intake of plant-based proteins to the detriment of animal-based proteins was associated with reduced sarcopenia risk. Study II revealed that increased poly-unsaturated fatty acids intake to the detriment of saturated fatty acids was associated with lower sarcopenia risk in older adults with a dietary protein intake below 1.1 g/kg of body weight. In Study III, beneficial links between dietary fibre intake and muscle mass were observed in older European adults. In Study IV, a one-year RCT promoting adherence to a Mediterranean-style diet did not result in significant changes in muscle strength or mass. In conclusion, the present dissertation emphasised the important potential of macronutrient amount and quality in the prevention of age-related loss of muscle strength and muscle mass. However, future experimental studies are warranted to clarify the impact of whole-diet approaches, such as the Mediterranean diet, on the maintenance of muscle health in older adults.
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| 2. |
- Bergens, Oscar, 1991-
(författare)
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Chronic Systemic Inflammation, Body Composition and Physical Activity Behaviours in Older Adults
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ageing is associated with a gradual physical decline accompanied by changes in body composition. The occurrence of a low-grade yet chronic state of systemic inflammation has gained interest for its potential consequences in the ageing process. Importantly, a physically active lifestyle may promote the maintenance of muscle mass, reduction in adipose tissue, and alleviate progression of a chronic pro-inflammatory state. The overall aim of this thesis was to explore relationships between biomarkers of systemic inflammation, body composition, and physical activity behaviours in community-dwelling older adults aged 65 to 70 years.A main finding of the thesis is the existence of associations between body composition and systemic inflammation in older adults, where excess adipose tissue is adversely associated with levels of inflammatory biomarkers in older women. Inverse associations were also observed between muscle mass and levels of pro-inflammatory biomarkers in older women. This thesis also highlights sex-specific associations between systemic inflammation and physical activity behaviours. Longer time spent sedentary was also associated with higher levels of proinflammatory biomarkers in older women and lower level of antiinflammatory biomarkers in older men. Reallocating time spent in activities of lower intensities with higher intensities was associated with lower levels of pro-inflammatory biomarkers in older women. Overall, the findings of this thesis support efforts promoting physical activity at the expense of sedentary time in order to combat age-related systemic inflammation and metabolic risk in older adults.
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| 3. |
- Edholm, Peter, 1977-
(författare)
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Muscle mass and physical function in ageing : the effects of physical activity and healthy diet
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ageing is associated with a gradual deterioration in physical function, accompanied by a decrease in muscle mass, leading to loss of independency. In this respect, physical activity and healthy diet represent key lifestyle factors with potential to delay onset of age-related physical disability. The overall aim of the present thesis was to explore the effects of physical activity behaviours in general and resistance training (RT) in particular, with or without addition of a healthy diet (HD), on muscle mass and physical function in older community-dwelling women. A main finding was that physical activity of at least moderate intensity at old age infers beneficial effects on physical function, even in individuals with a previously sedentary lifestyle. Additionally, engagement in exercise-related activities during middleage years is linked to better physical function and higher muscle massat old age, regardless of present physical activity level. This thesis further highlights that in older women RT combined with HD rich in omega-3 polyunsaturated fatty acids elicits significant gains in muscle mass, whereas no corresponding gain was induced by RT alone. Likewise, larger improvements in muscle strength and physical function were evident in response to combined effects by RT and HD compared to RT alone. Taken together, findings from this thesis support public health efforts aiming to promote physical activity of at least moderate intensity together with a healthy diet rich in omega-3 polyunsaturated fatty acids in order to combat age-related decline in muscle mass and physical function.
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| 4. |
- Strandberg, Emelie, 1986-
(författare)
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Skeletal Muscle Mass & Function in Older Women : Health-Enhancing Influences of Combined Resistance Exercise & Diet
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ageing is accompanied by a progressive decline in skeletal muscle mass and strength which may lead to impaired ability to perform activities of daily living in older adults. Although the exact cause of the gradual decline in muscle mass is unknown, identifying efficient strategies aiming to prevent age-related loss of muscle mass and strength is important in order to promote healthy ageing. The overall aim of this thesis was to explore the effects of resistance training alone or combined with a healthy diet on skeletal muscle mass and function of healthy recreationally active older women and to determine mechanisms by which elevated systemic inflammation may contribute to the age-related decline of muscle mass in older adults. The combination of resistance training and a healthy diet induced gains in leg lean mass as well as greater gains in dynamic explosive force than resistance training alone in healthy recreationally active older women. The observed gains in leg lean mass were accompanied by increases in the size of type IIA muscle fibres together with down-regulation in gene expression of a pro-inflammatory factor (IL-1β) and upregulation in gene expression of a regulator of cellular growth (mTOR) in skeletal muscle of older women. Additionally, reduced muscle protein synthesis and size of muscle cells may mediate the detrimental effects of elevated circulating markers of inflammation on muscle mass in older adults. In conclusion, the present thesis depicts mechanistic links between elevated systemic marker of inflammation and muscle mass and provides new information on the effects of combined resistance training and healthy diet on muscle mass and strength in a group of healthy recreationally active older women. This knowledge is instrumental for development of strategies aiming to prevent age-related loss of muscle mass and function.
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| 5. |
- Folkesson, Mattias, 1972-
(författare)
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Heat shock proteins in exercised human skeletal muscle
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Exercise is considered as an important stressor accompanied by concerted molecular and cellular changes leading to adaptations at the level of skeletal muscle size and function. An important protein family produced by cells in response to stressful conditions is the heat shock proteins (HSPs). It is suggested that the different HSPs play specific roles in acute and longterm responses to exercise-induced stress. The overall aim of this thesis was to explore the expression of four different HSPs (αB-crystallin, HSP27, HSP60 and HSP70) in human skeletal muscle exposed to exercise, with a special emphasis on the role played by HSP27 in the hypertrophy of human skeletal muscle.One of the major findings was the fibre type-specific expression of HSPs in resting human skeletal muscle, including the preferential expression of HSP27 in fast type II muscle fibres. Another finding was the occurrence of training background-related differences in the expression of HSPs. Also, a cytoplasmic relocation of HSP27, occurring specifically in type II muscle fibres, was shown in response to a single bout of resistance exercise. Interestingly, there were no corresponding changes in response to an endurance exercise bout, suggesting that HSP27 may be specifically involved in the adaptations to resistance exercise. In order to test this hypothesis, an in-vitro exercise model based on the electrical pulse stimulation (EPS) of muscle cells was developed. The EPS protocol, including an 8 h restitution period, induced a significant hypertrophy of muscle cells together with molecular changes similar to those previously described in response to exercise in humans. The role of HSP27 in the hypertrophy of human muscle cells was examined through the downregulation of HSP27. Based on data from morphological and microarray analyses, findings indicate that HSP27 is not mandatory for the hypertrophy of human muscle cells. Overall, the present thesis clarified the expression of different HSPs in human skeletal muscle and provided an in-vitro-based approach for the elucidation of the exact role played by HSPs in the adaptations of human skeletal muscle to exercise.
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| 6. |
- Papaioannou, Konstantinos-Georgios, 1983-
(författare)
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Diet and physical activity behaviors for healthy aging
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The process of aging is characterized by physiological changes in various body systems and biological functions, that affect health and functional capacity. Adopting healthy lifestyle behaviors could be an effective, accessible, and lowcost strategy to delay age-related functional changes. Dietary habits, including both patterns and amounts of specific food items, and physical activity (PA)are two lifestyle factors that may have an impact on several age-related health aspects. The overall aim of this thesis was to determine the links between diet, physical activity behaviors, and biological markers of healthy aging, including muscle health, metabolic health, and systemic inflammation in older adults.The findings of the present work collectively highlight the role of diet and physical activity behaviors on biological markers of healthy aging in older adults. Daily amounts of sedentary time were detrimentally associated with the systemic inflammatory environment, with sex-specific alterations in proand anti-inflammatory biomarkers. In term of dietary habits, higher intakes of vegetables were associated with lower levels of the pro-inflammatory biomarker IL-6 in older adults, regardless of intakes of other health-related food groups, physical activity behaviors, and adiposity level. Moreover, lower intakes of fruit and vegetables (FV) in general, and of vegetables in particular, increased the likelihood of having metabolic syndrome (MetS) in older adults, which was evident even after considering time spent in sedentary behavior and adherence to the moderate-to-vigorous physical activity (MVPA) guideline. Finally, healthy eating was beneficially associated with lower sarcopenia risk in physically active older men and women, even when engagement in musclestrengthening activities and adherence to guidelines for protein intake were considered. Overall, the present thesis demonstrates the detrimental impact of excessive amounts of sedentary time on markers of systemic inflammation and highlights the beneficial effects of healthy eating on biological determinants of healthy aging regardless of the potential confounding effects of physical activity behaviors.
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| 7. |
- Veen, Jort, 1975-
(författare)
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Physical activity, muscle mass and physical function in older adults
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ageing is accompanied by a decline in physical function, including loss of muscle mass and muscle strength, which leads to impaired ability to perform activities of daily living and loss of independence. Physical activity (PA) is currently viewed as a key lifestyle factor with potential to mitigate these age-related deteriorations. Therefore, public health organizations have issued guidelines about amounts and types of physical activity for health benefits, where reductions in daily time spent sedentary in favour of more time in aerobic-type moderate-to-vigorous PA (MVPA) are emphasized. In addition, regular engagement in musclestrengthening activities (MSA) are recommended to promote maintenance of muscle mass and strength in ageing populations. However, to what extent different amounts and types of PA impact on different indicators of physical function, including muscle mass and strength, remains currently unclear. Therefore, the overall aim of this thesis was to investigate the impact of PA behaviours on muscle mass and physical function in older adults. In study I, it was shown that regular engagement in exercise activities during middle age was associated with a significantly higher muscle mass and a better cardiorespiratory fitness at old age. In study II, replacement of daily sedentary time with PA of at least light intensity was associated with a significantly lower sarcopenia risk in older adults, with greater benefits above the moderate PA intensity. Study III revealed that engagement in MSA at least twice a week was linked to a significantly lower sarcopenia risk in older adults who already perform at least 150 weekly minutes of MVPA. Finally, study IV showed that older adults who accumulate at least 300 weekly minutes of MVPA have a significantly better overall physical function than those who accumulate at least 150 but less than 300 minutes of MVPA per week. Overall, the findings from this thesis highlight the importance of adherence to the aerobic-type MVPA guideline alongside recommended engagement in MSA for mitigating age-related decline in physical function in older adults. Notably, accumulation of MVPA time beyond the minimum recommended amount provides additional functional benefits.
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