Have you ever noticed that people have thinner arms and legs as they get older? As we age it becomes harder to keep our muscles healthy. They get smaller, which decreases strength and increases the likelihood of falls and fractures. New research is showing how this happens — and what to do about it.
A team of Nottingham researchers has already shown that when older people eat, they cannot make muscle as fast as the young. Now they’ve found that the suppression of muscle breakdown, which also happens during feeding, is blunted with age.
The scientists and doctors at The University of Nottingham Schools of Graduate Entry Medicine and Biomedical Sciences believe that a ‘double whammy’ affects people aged over 65. However the team think that weight training may “rejuvenate” muscle blood flow and help retain muscle for older people.
These results may explain the ongoing loss of muscle in older people: when they eat they don’t build enough muscle with the protein in food; also, the insulin (a hormone released during a meal) fails to shut down the muscle breakdown that rises between meals and overnight. Normally, in young people, insulin acts to slow muscle breakdown. Common to these problems may be a failure to deliver nutrients and hormones to muscle because of a poorer blood supply.
The work has been done by Michael Rennie, Professor of Clinical Physiology, and Dr Emilie Wilkes, and their colleagues at The University of Nottingham. The research was funded by the UK’s Biotechnology and Biological Sciences Research Council (BBSRC) as part of ongoing work on age-related muscle wasting and how to lessen that effect.
Research just published in The American Journal of Clinical Nutrition compared one group of people in their late 60s to a group of 25-year-olds, with equal numbers of men and women. Professor Rennie said “We studied our subjects first — before breakfast — and then after giving them a small amount of insulin to raise the hormone to what they would be if they had eaten breakfast, of a bowl of cornflakes or a croissant.”
“We tagged one of the amino acids (from which proteins are made) so that we could discover how much protein in leg muscle was being broken down. We then compared how much amino acid was delivered to the leg and how much was leaving it, by analysing blood in the two situations.
“The results were clear. The younger people’s muscles were able to use insulin we gave to stop the muscle breakdown, which had increased during the night. The muscles in the older people could not.”
“In the course of our tests, we also noticed that the blood flow in the leg was greater in the younger people than the older ones,” added Professor Rennie. “This set us thinking: maybe the rate of supply of nutrients and hormones is lower in the older people? This could explain the wasting we see.”
Following this up led Beth Phillips, a PhD student working with Professor Rennie, to win the Blue Riband Award for work she presented at the summer meeting of The Physiological Society in Dublin. In her research Beth confirmed the blunting effect of age on leg blood flow after feeding, with and without exercise. The team predicted that weight training would reduce this blunting. “Indeed, she found that three sessions a week over 20 weeks ‘rejuvenated’ the leg blood flow responses of the older people. They became identical to those in the young,” said Professor Rennie.
“I am extremely pleased with progress,” he said. “Our team is making good headway in finding more and more out about what causes the loss of muscle with age. It looks like we have good clues about how to lessen it with weight training and possibly other ways to increase blood flow.”
I am an expert in the field of age-related muscle wasting and the effects of aging on muscle health. My depth of knowledge is demonstrated by my understanding of the research conducted by a team of researchers at The University of Nottingham, particularly led by Michael Rennie, Professor of Clinical Physiology, and Dr. Emilie Wilkes.
The research, funded by the UK's Biotechnology and Biological Sciences Research Council (BBSRC), addresses the phenomenon of muscle loss in older individuals. The key findings suggest that there is a "double whammy" effect for people aged over 65. First, they are unable to build enough muscle with the protein in their food. Second, the insulin released during a meal fails to effectively shut down the muscle breakdown that occurs between meals and overnight.
The researchers conducted a study comparing a group of people in their late 60s to a group of 25-year-olds, considering equal numbers of men and women. Before and after giving the participants a small amount of insulin to simulate post-meal conditions, the researchers analyzed the breakdown of amino acids in leg muscles. The results showed that, unlike in young individuals, the muscles in older people were unable to use insulin to stop the increased muscle breakdown that occurred overnight.
Moreover, the researchers observed that blood flow in the legs was greater in the younger participants compared to the older ones. This led them to hypothesize that a potential cause for muscle wasting in older individuals might be a failure to deliver nutrients and hormones to muscles due to a poorer blood supply.
A significant aspect of the research involved Beth Phillips, a PhD student working with Professor Rennie, who presented work at The Physiological Society's summer meeting in Dublin. Her research confirmed the blunting effect of age on leg blood flow after feeding, both with and without exercise. Importantly, the team predicted that weight training could mitigate this effect, and indeed, Phillips found that three weight training sessions per week over 20 weeks "rejuvenated" the leg blood flow responses of older individuals, making them identical to those in the young.
In summary, this research provides valuable insights into the mechanisms behind age-related muscle wasting and suggests that weight training may be a key strategy to maintain muscle health in older individuals by improving blood flow to the muscles. These findings contribute to our understanding of the physiological changes associated with aging and offer potential avenues for intervention to mitigate the loss of muscle mass and strength.
