How to stay slim in midlife? Lift weights
It’s vital for weight control and staying sharp but most of us never do strength training, says Caroline Williams
You’re nailing the step target, don’t get out of breath on the stairs and are fairly confident that you could run to catch a bus if necessary. But it’s still possible that you are missing a crucial aspect of health and fitness. According to a growing body of research, strength training, once seen as an optional extra, should be considered at least as important as aerobic exercise. That could include everything from lifting weights to carrying heavy shopping. Activities like these, which stress the muscles, are being shown to have benefits beyond aerobic exercise – and be important for weight control in middle age.
In a study published in June, researchers at Iowa State University looked at records for 12,000 mostly middle-aged adults, and found that two or more sessions of weight training a week was enough to reduce the risk of obesity by 20 to 30 per cent over two decades, even for people who do no aerobic exercise. Ramping it up to one or two hours a week was even more effective, reducing the risk of obesity by 30-40 per cent. Other bonus effects include reduced cholesterol, inflammation and blood pressure, and a reduced risk of diabetes and heart disease.
Muscular strength has been linked to a longer life, a lower risk of obesity, and a healthier brain, bone quality and cardiovascular system. It has also been shown to improve self-esteem, boost confidence and reduce the symptoms of anxiety and depression.
But there are signs that even people who exercise regularly are neglecting their strength. “At the population level, approximately 60 per cent do no strength training. This is almost double those who do no aerobic exercise,” says Jason Bennie, an exercise epidemiologist at the University of Southern Queensland in Australia.
The benefits of adding strength to the mix can be significant. According to a recent analysis, people who did regular muscle-strengthening exercise were 21 per cent less likely to die from any cause over the following decade, regardless of their age and how much aerobic exercise they also did.
The reasons why are complex but seem to come down to giving the body something constructive to do with its spare calories. Challenging the body to lift weight stimulates it to maintain muscle capacity it already has, and to add more if necessary. The energy for this can come from stored fat or sugar or from any extra calories taken in through the diet. The build-and-repair process continues long after we finish exercising, with muscle continuing to burn calories for up to 24 hours.
Once new muscle is in place, it’s the metabolic gift that keeps giving. Muscle is packed with mitochondria, the factory-like parts of the cell that turn glucose into energy. Having more muscle on board means that the body has more factories to run, and so burns more calories, even at rest.
These benefits also extend to the brain. Higher levels of overall strength
Once new muscle is in place, it’s the metabolic gift that keeps giving
are associated with better performance on tests of cognitive skills such as memory and decision-making. It also seems to keep the brain healthy for longer. Like other forms of exercise this likely comes down to a mix of better circulation, and a boost to maintenance and repair, thanks to the release of various growth factors, which add new neurons and connections in the brain. There may be something else going on, however, that is particularly relevant to the importance of weights.
When we put weight on our bones they release a hormone called osteocalcin into the blood where it travels to the brain, and connects with the hippocampus, a key brain region involved in memory.
Only a few studies have been done so far in humans, but those that have suggest that osteocalcin is indeed important for memory, particularly as we age. From middle age onwards, levels of osteocalcin start to decline, making weight-bearing exercise all the more important to protect the brain.
A lack of osteocalcin has also been linked to anxiety in animal studies – and resistance exercise has been shown to be particularly effective in relieving depression and anxiety and to boosting levels of self-esteem.
As far back as the late 80s, studies suggested that increasing physical
strength could have outcomes for mental health. A group of teenage girls who did weights to boost their strength by 40 per cent over 12 weeks, for example, reported not only feeling stronger physically but mentally, too, with more confidence in tricky social situations or arguments and greater belief in their “general effectiveness in life”. Other studies suggest that while this is also true of aerobic fitness, weight training seems to have an edge, at least in the short term.
It’s not exactly clear why this should be, and osteocalcin is almost certainly not the whole story. One idea is that our brains make a call on what we can handle based not only on what’s in our heads, but also via an unconscious sense of what our bodies are capable of, fed in through the muscles. Getting stronger provides an underlying confidence in your abilities that makes life feel that much more doable.
The clear message from the research is that at every stage of life, no matter how aerobically fit you are, adding a bit of resistance training will pay dividends. In young people, it’s important not only for confidencebuilding, but to build strong bones and muscles as insurance for when both start to decline from middle age. From then on, it’s a question of maintaining what you’ve got for as long as possible.
“We all lose muscle mass and muscle strength with age, and maintaining it is so much easier than increasing it,” says Tessa Strain, an exercise epidemiologist at Cambridge University. Having a certain level of strength is crucial to allow people to live independently for longer, she adds – like having the leg strength to get up out of a chair. “There comes a point where it doesn’t matter how aerobically fit you are. There’s a level of strength we all need to operate in life”.
The current UK guidelines, which were updated in 2019, recommend doing strength training at least twice a week, on top of (or as part of) the recommended 150 minutes of moderate intensity or 75 minutes moderate-to-vigorous exercise.
This doesn’t have to mean lifting weights at the gym. Heavy gardening, carrying shopping, hill walking and swimming, all boost physical strength as do sports like cycling, tennis and climbing. Even sitting on the floor more often is a great way to increase leg strength, because at some point you’re going to have to get up. Strain points out that what’s most important is to work all the major muscle groups – legs, arms, core, chest and back. An easy way to make sure you’re hitting all these targets is to do body weight exercises like push ups, squats and lunges. There are countless options online including chair exercises for the less mobile, and the NHS website has a series of 10-minute body-weight exercise routines that can be done at home. The NHS advises that strength exercises should be done “to the point where you need a short rest before repeating the activity.”
Ideally, says Strain, we should combine aerobic exercise with resistance exercise to get the best possible outcomes. But even those who hate rushing around and getting out of breath should still prioritise building strength. In short: if in doubt, lift.
Caroline Williams is the author of Move! The New Science of Body Over Mind (Profile Books, £16.99). Buy the ebook for £11.38 from books.telegraph.co.uk