Comment: Five common myths about the ageing brain and body Published on: 24 January 2017 Writing for The Conversation, Dr Blossom Stephan and Dr Hannah Keage look at the changes and processes that occur in our body as we age. , and , This article is part of our series on . It looks at the changes and processes that occur in our body as we age, the conditions we鈥檙e more likely to suffer from and what we can do to prevent them. The world鈥檚 population, and Australia鈥檚, is ageing. The number of adults aged 65 and over is , as is the proportion of the population they represent. However, there are a number of myths associated with what happens to our brain and bodies as we age. 1. Dementia is an inevitable part of ageing Dementia prevalence increases with age. That is, your chance of having a diagnosis of dementia is greater the older you are. But if you are lucky enough to reach old age, you won鈥檛 necessarily have dementia. Dementia is a clinical diagnosis that is characterised by impairments in cognition (the way we think) and functional abilities (that enable us to live independently). The major type of dementia is Alzheimer鈥檚 disease, although there are many other types, such as vascular dementia (related to vascular changes in the brain such as stroke), frontotemporal dementia (brain atrophy most pronounced in temporal and frontal cortical regions of the brain), Lewy body dementia (related to a particular protein deposit called a Lewy body) and mixed - where different types occur at the same time. However, 65-69 years of age have a dementia diagnosis, and this rises to over 30% for those 90 years and over. The flip side of this is that nearly 70% of those aged 90 years and over don鈥檛 have dementia. In Australia in 2014, the was 79 years for males and 85 years for females; so, most of us won鈥檛 die with a dementia diagnosis. 2. Cognition declines from the 20s Cognition refers to the way we think, but there are lots of types of thinking skills. For example, the speed at which we can respond (processing speed), our ability to remember objects (general memory), and our knowledge of words and their meaning (vocabulary knowledge). These cognitive domains show different patterns of change across adulthood. Processing speed and general memory do appear to decline from the 20s, which means we are slower at responding to relevant cues and a bit more forgetful as we age. But this is not the case for vocabulary knowledge. On average, we will reach our , and our performance will not markedly decline after that. In fact, the older your age, the better your performance on the New York Times crossword. 3. I can鈥檛 change my risk of dementia It has been estimated that are preventable through lifestyle choices. Evidence shows mid-life heart factors, especially diabetes, high blood pressure, obesity and physical inactivity, increase the risk of developing dementia in late-life, as does having depression, smoking and having low educational attainment. So, one way to decrease your risk of dementia is to reduce your heart risk factors - for example, exercise more and reduce your weight if you are obese. Engaging with cognitively stimulating activities such as formal (such as university) and informal (such as short-courses) education, and social meetings, has been shown to reduce the risk of dementia. This evidence ties in nicely with from Europe and the US, which have demonstrated an individual鈥檚 risk of dementia has actually decreased over the past two decades. Why? Well, it is appears that older adults are now more physically and cognitively healthy than their predecessors. 4. I鈥檒l get dementia if my parents did Late-life dementia, which is diagnosed when you are 65 years and over, is only influenced slightly by the genetics your parents passed onto you. Nine genes have been identified that either increase or decrease your risk for dementia. There is one that carries some influence: apolipoprotein E. If you have one combination (E4E4 alleles), you are at 15 times more likely to get dementia as someone with the more typical combination (E3E3). However, all other identified genes have only a small effect, with each putting you at a of developing the disease. To put these genetic risks in perspective, they are smaller than each of the lifestyle factors mentioned above. That is, dementia is more likely to be caused by obesity (60% more likely) or being inactive (80% more likely). These comparisons are not perfect, as it may be that genes related to dementia also relate to these lifestyle factors, but it does show how powerful lifestyle factors are. 5. My weight will stay the same Simple physics energy laws tell us that if the calories we are eating match the energy we are burning, our weight will essentially be stable. Most people believe in this simple and truthful nutritional dogma, but fail to take into account the significant effects of ageing on energy metabolism. As we age, our body composition changes. In particular, we tend to have a reciprocal change in fat (increase) and muscle (decrease), and these changes appear to be different in men and women. Men appear to have a , which accounts for a decline in the total energy expenditure of about 3% per decade. In women, the compared to men (about 2% per decade). This simply means if you continue to eat and exercise at the same level as you age, you will likely gain weight, and this will mostly consist of body fat. Ageing is not a passive biological process. We need to better understand our body and its changes if we want to maintain health and prevent the onset of diseases such as dementia. Read other articles in the series . , Senior Lecturer in Psychology, and , Senior lecturer, This article was originally published on . Read the . Share: Latest News 缅北禁地 expert highlights climate crisis in a new film A leading 缅北禁地 climate scientist is featured in a new film about how the climate and nature breakdown will affect the UK. published on: 14 April 2026 Neolithic tombs reveal ancient kinship ties Male individuals buried in Neolithic chambered tombs in northern Scotland were often related to each other through the paternal line and some were interred in the same or nearby tombs, research shows. published on: 14 April 2026 We are our Memories New exhibition by Fine Art graduate Trish Hudson-Moses, 22 April 鈥� 4 May 2026 published on: 10 April 2026 Facts and figures
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