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The East African : Aug 29th 2015
The EastAfrican OUTLOOK AUGUST 29 - SEPTEMBER 4, 2015 35 health could be at risk Comparing the slower and faster ageing groups is important since it can reveal ways of delaying ageing in life. According to Nairobi-based con- sultant physician Daniel Abongo, the research can also help scientists understand better the factors that influence ageing, especially among the youthful population. “If successful, the research will not only help us better understand the causes of ageing but also how to slow the process using medication and other means,” said Dr Abongo. Though there has been scepticism about whether the ageing process can be detected in young adults who do not have chronic diseases, the researchers found otherwise. They found that the ageing processes can be quantified in people young enough to prevent age-related diseases. Once the individual in the study celebrated their 38th birthday, for example, the scientists examined their physiologies to test whether the population would show evidence of individual variation in ageing despite remaining free of age-related disease. “We further tested whether, by midlife, young adults who were ageing more rapidly already exhibited deficits in their physical functioning, showed signs of early cognitive decline, and looked older to independent observers,” the researchers added. They found that study members with advanced biological ages had experienced a more rapid pace of ageing over the past 12 years compared with their biologically younger peers. Each year, an increase in biologi- Comparing the slower and faster ageing groups can reveal ways of delaying ageing.” cal age was associated with a 0.05year increase in the pace of ageing relative to the population norm. In other words, a 38-year-old with a biological age of 40 years was estimated to have aged 1.2 years faster over the course of the 12-year follow-up period, compared with a peer whose chronological age and biological age was 38. “This estimate suggests that a substantial component of individual differences in biological age at midlife emerges during adulthood,” the study added. Study members with advanced biological age did not perform as well on objective tests of physical functioning at age 38 as biologically younger peers. “They had more difficulty with balance and motor tests (for unipedal stance test of balance; for grooved pegboard test of fine motor co-ordination), and they were not as strong (grip strength test),” the study said. The study also discovered that accelerated ageing in young adults also influenced indicators of brain ageing. Study members with older biological ages had poorer cognitive functioning at midlife. Healthy adults who were ageing faster showed evidence of cognitive decline and increased risk for stroke and dementia relative to slower-ageing peers. They also felt less healthy and were rated as looking older by independent observers. the≥e’s no science behind it tell you that I have rarely, if ever, used urine osmolality as the means by which I decide if a child is dehydrated. When I asked colleagues, none thought 800mOsm/kg was the value at which they’d be concerned. And in a Web search, most sources I found thought values up to 1,200mOsm/kg were still in the physiologically normal range and that children varied more than adults. None declared that 800mOsm/kg was where we’d consider children to be dehydrated. That hasn’t stopped more recent studies from continuing to use the 800mOsm/kg standard to declare huge numbers of children to be dehydrated. A 2012 study in the Annals of Nutrition and Metabolism used it to declare that almost two-thirds of French children weren’t getting enough water. Another in the journal Public Health Nutrition used it to declare that almost two-thirds of children in Los Angeles and New York City weren’t getting enough water. The first study was funded by Nestlé Waters; the second by Nestec, a Nestlé subsidiary. It’s possible that there are children who need to be better hydrated. But at some point, we are at risk of calling an ordinary healthy condition a disease. When two-thirds of healthy children, year after year, are found to have a laboratory value that you are labelling “abnormal,” it may be the definition, and not their health, that is off. None of this has slowed the tidal push for more water. It has even been part of Michelle Obama’s “Drink Up” campaign. In 2013, Sam Kass, then a White House nutritional policy adviser, declared “40 per cent of Americans drink less than half of the recommended amount of water daily.” There is no formal recommendation for the daily amount of water people need. That amount obviously differs by what people eat, where they live, how big they are and what they are doing. Young adult man and woman stretching.x. Pic: File The ≥ight dose of exe≥cise fo≥ ageing b≥ain By GRETCHEN REYNOLDS New York Times News Service A SMALL amount of exercise may improve our ability to think as we age, but more may not be better, according to a new study of exercise and cognition. We all know that working out is good for us. But how much or how little exercise is needed to gain various health benefits, and whether the same dose of exercise that bolsters heart health, for instance, is also ideal for the brain has remained unclear. For a new study, published last month in PLOS One, scientists with the University of Kansas Alzheimer’s Disease Centre and other institutions recently decided to see if they could determine just how much exercise is needed to improve the ability to think. They began by recruiting 101 sedentary older adults, at least 65-years-old, who were generally healthy, with no symptoms of dementia or other cognitive impairments. The scientists brought these vol- unteers to the laboratory and had them complete a series of tests, including measurements of their aerobic capacity and how well they could remember and think. Then the volunteers were ran- domly assigned to one of four groups. People in the control group continued their normal lives. People in the other three groups were assigned to walk briskly. One group began exercising for 75 minutes a week, which is half of the current recommendation of 150 minutes a week of moderate exercise. Another group was assigned to exercise for the recommended 150 minutes. And the third group was directed to exercise for 225 minutes a week, or 150 per cent of the recommended amount. The exercising consisted of su- pervised brisk walks on a treadmill for 25 minutes to an hour. After 26 weeks, all of the par- ticipants returned to the lab to repeat the original tests. At this point, the groups dis- played notable differences, especially in a physical sense. The more someone had exercised, the more his or her endurance capacity had increased, which was hardly a surprise. The volunteers in the control group were no more fit than they had been; those in the group exercising for 75 minutes a week were somewhat more fit; those exercising for 150 minutes a week were fitter still; and those walking for 225 minutes a week were the fittest of all. “There was a very clear dose- response relationship” between walking and fitness, said Dr Jeffrey Burns, a director of the University of Kansas Alzheimer’s Disease Centre and the study’s senior author. That relationship was murkier when the scientists looked at thinking, however. In general, the researchers found, most of the exercisers showed improvements in their thinking skills, especially in their ability to control their attention and to create visual maps of spaces in their heads, two aspects of cognition that are known to decline with age. But these gains were about the same whether people had exercised for 75 minutes a week or 225 minutes. Those volunteers who had exercised the most scored slightly better on some cognitive tests at the end of the study period than those exercising less, but the difference was barely significant. Overall, “a small dose of exer- cise” may be sufficient to improve many aspects of thinking, and more sweat may not provide noticeably more cognitive benefit, Dr Burns said. On the other hand, more ex- ercise will likely make you more aerobically fit, Burns said, which has other health effects. This dichotomy underscores the importance for scientists to do a better job of nailing down how different amounts of exercise differently affect us, Burns said. In the meantime, though, the encouraging takeaway from the new study, he pointed out, is that briskly walking for 20 or 25 minutes several times a week — a dose of exercise achievable by almost all of us — may help to keep our brains sharp as the years pass.
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Sep 5th 2015