Muscle mass, quality, and the menopause: sex-specific strategies to mitigate sarcopenia in aging populations

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As we grow older, our muscles become smaller and weaker (sarcopenia), which can make it more difficult to complete daily activities and can increase our reliance on healthcare systems. The UK has a growing ageing population, and, therefore, sarcopenia represents a major healthcare concern, (for example, its estimated cost to the UK healthcare system in 2016 was £2.5 billion). There is an urgent need to develop strategies to prevent sarcopenia. However, these strategies need to be targeted, with evidence suggesting that older men and women develop sarcopenia differently. For instance, sarcopenia develops earlier in women, resulting in greater levels of physical disability compared with men. The underlying sex differences with ageing are unclear, yet the earlier prevalence of sarcopenia in women coincides with the menopause. The menopause is a change in the sex hormone environment that is a part of normal female ageing and is associated with changes in body composition including muscle loss and increased body fat. This increase in body fat can become located within muscle, further accelerating the loss of muscle strength and poor health. There is a lack of understanding of how these changes in body composition occur. However, for muscle to decrease in size, there must be an imbalance between how quickly we remove muscle proteins and how quickly we make new muscle proteins. We have recently developed advanced biochemistry techniques to measure how quickly we make and remove muscle proteins. By applying these techniques to pre- and post-menopausal women, we will be able to better understand muscle protein balance during ageing for the first time. By combining these techniques with magnetic resonance imaging (MRI), we will develop new methods to locate where, and how quickly, new fat is deposited in the body. Combined, these approaches will provide vital insights on how best to target future interventions against sarcopenia in women. Resistance exercise therapy (RET) currently offers the most effective strategy to promote muscle mass and strength in ageing. However, responses to resistance exercise are blunted in older women compared to younger women. We will measure whether the menopause has an impact on how quickly new muscle proteins are made in response to exercise, and, using our MRI imaging techniques, we will monitor whether RET alters the rate of fat deposition in the body. Together, these measures will determine the effectiveness of RET at slowing sarcopenia and improving body composition in post-menopausal women. Using our results, we will create evidence-based resources and information, and implement these recommendations into menopause intervention programmes through existing connections with Sport England Active Partnerships (Active Together in Leicestershire and Sport Notts), Sports Exercise Medicine departments at the Universities of Nottingham and Leicester and the National Centre for Sport and Exercise Medicine in Loughborough, as well as the national "Moving Medicine" website for doctors, the Exercise Medicine clinic at Leicester General Hospital, and menopause clinics in Leicester and Nottingham.