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The Impact of Leg Strength on Life Expectancy and Brain Health
By Ben Holm
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Never skip a Monday. This is one of the most well-known pieces of advice for anyone focused on health and fitness, but science is proving that we should all pay attention to one more rule for success: Never skip leg day. In fact, it’s probably best to think of every day as leg day because strength in this one area of your body will likely determine your longevity and how well you maintain your cognitive health through the years.
What’s the connection between leg strength, longevity and the brain? When you look at some of the most fascinating scientific studies released in recent years, it becomes clear that your legs are more powerful than ever imagined.
Leg Strength and Life Expectancy
Much of the research that now connects leg strength and life expectancy began with the Health, Aging and Body Composition Study, which is commonly referred to as the Health ABC Study. Researchers recruited 3,075 men and women who could walk a quarter of a mile and climb 10 steps without difficulty at the start of the study.
Participants answered telephone questionnaires and went through milestone testing for a total of 16 years with a retention rate close to 100 percent. The goal was to study changes in body composition and health over time, looking for factors that could reasonably predict levels of health later in life. A massive amount of data was collected, and researchers are now using that information as a jumping off point for additional scientific studies.
One thing we do know about the Health ABC Study is that the leg strength of participants at the start of the study was a predictor of the health they enjoyed later in the study. One follow-up study utilized data for men and women participating in the Health ABC Study to determine that lower intake of protein earlier in life may lead to greater loss of skeletal muscle later in life, increasing the risk of “functional impairment and mortality” with age.
Other researchers have come up with the same results when studying predictors of reduced physical functioning late in life. One study utilized data from 1,280 adults aged 55 and older to determine that leg strength was the biggest predictor of physical functionality in the future. Another study published in 2017 through the European Journal of Clinical Nutrition found that hemodialysis patients were less likely to die from cardiovascular disease or any other cause if they had adequate muscle mass in the lower thigh.
If we go back to 2006, there was an interesting study published in the Journal of Gerontology that found quadricep strength was an efficient predictor of mortality risk. This study utilized the data of 2,292 participants from the Health ABC Study.
In 2012, BMJ published research proving that low muscle strength in adolescence is a clear predictor of mortality in young adulthood. This study followed more than a million adolescent men for 24 years, so it’s important to note the lack of women in this study. A study from 2010 also found that leg strength is a predictor of mortality in men with peripheral artery disease but not for women with the same disease. Perhaps future research will tell us with certainty what may serve as a stronger predictor for women.
For anyone trying to live as long as possible and make the most of those years, there are three things to learn from these studies:
- The stronger you are today, the longer you’re likely to live in the future.
- Strength in your legs is likely a bigger predictor of future health than the amount of muscle you have overall.
- Consuming an adequate amount of protein is key to maintaining your muscle and strength as you get older. You don’t want to consume too much protein, but you can give your body a boost on muscle retention by switching out the carbs for an extra serving of chicken or turkey whenever possible. Many factors go into determining how much protein you need, but it’s worth a little exploration.
Leg Strength and the Aging Brain
We’ve known for a long time that cognitive functioning declines with age. This refers to the ability to receive information from your surrounding environment, process that information for meaning, and then either act on it immediately or store it for future use. This includes memory, processing speed and the ability to concentrate on one thing for a period of time.
What we haven’t always known is the connection between physical strength in the early years of life and cognitive functioning in later years. One study published in a 2016 issue of Gerontology compared the leg strength and cognitive functioning of 324 female twins over a 10-year period to see if they could establish a protective connection when comparing data between each twin set.
This research is groundbreaking because it eliminates a variety of genetic and environmental factors that may come into play when comparing unrelated study participants. When each twin was compared to her sister, the data showed that those with more leg strength at the beginning of the study were in better cognitive shape at the end of the study.
They also found that leg strength early in life can predict the amount of grey matter in the brain later on. Since we know that the development of grey matter declines with age and is connected to memory and other cognitive abilities, this study makes a strong argument that keeping the leg muscles strong can lead to more grey matter and thus improved cognitive abilities later in life.
Another study published in a 2018 issue of Frontiers in Neuroscience used mice to prove that weight-bearing exercise is critical to the production of neural stem cells and the maintenance of muscle mass. Researchers stopped mice from using their hind legs for 28 days, dramatically reducing their mobility and leg strength. The result was less muscle mass and a reduction in the number of neural stem cells in their brains.
When these stem cells aren’t produced and utilized properly, it can have a devastating impact on the central nervous system and may increase the risk of developing neurological disorders like multiple sclerosis. This study also proves that there is a protective relationship between the leg muscles and the brain. If your leg muscles are weak or you aren’t able to move them frequently, it has a negative impact on brain functioning.
Is it really a shock that studies are showing a connection between leg strength and cognitive diseases like Alzheimer’s and dementia? Wherever you are in your life right now, the term “move it or lose it” should stay at the front of your mind.
Something as simple as moving your legs more could keep your mind alive and your body in motion for decades to come. Here’s the great news: It’s never too late to start building leg strength. Even if you’re in your 40s or well beyond, you will benefit from doing everything possible to strengthen your lower body. Keep reading for some great ideas on how to do this efficiently and safely.
How to Improve Leg Strength at Any Age
Combine everything we have learned so far with the fact that most people will lose a quarter of their muscle strength by the age of 70, and it’s not difficult to see why late-life disease is running rampant and ending lives way too early. Improving your activity level or going for casual walks isn’t enough to maintain leg strength, but those activities may serve as your starting point.
Use this cheat sheet as a guide to determine how you take action to pump up your legs starting today:
- If your lifestyle is currently sedentary, start by getting up and moving as much as possible. If taking short walks throughout the day is all that you can do safely, then that’s your starting point. If you can do strength-building exercises during commercial breaks when watching television as well, then that’s even better. Think about seeing your doctor to determine what you can do safely, and then gradually build up to a more rigorous workout routine with time. We’ll tell you about some of the simplest and most effective leg-strengthening exercises below, so jump down for the list and start using them as much as possible.
- If you’re moderately active but you don’t workout consistently, it’s time to take your workout routine to the next level. You don’t have to designate certain days “leg day,” but you should start adding some weight-bearing exercises that target your leg muscles into your routine. Look below for a list of leg exercises proven to strengthen and build muscle.
- If you workout regularly or you’re an athlete, then you probably already have strong leg muscles. Make it a rule never to skip leg day, and maybe consider increasing the amount of time that you focus on your legs.
Research has shown that runners have strong leg muscles that can extend their lives by nearly two decades, and it’s likely that other athletes who regularly train their leg muscles have the same benefit. Perhaps you’re not an athlete or runner, but you can still participate in sports.
You’ll work the same muscles whether you’re playing basketball at the YMCA with the kids or on a professional court. Tennis, badminton, soccer and flag football will work as well. If you can’t run, start with power walking.
Swimmers also have strong legs, and exercising in the water applies virtually no impact on your body. This makes water aerobics and swimming laps another great starting point for those unable to move comfortably on dry land. Try walking laps across the shallow end of the pool while lunging and kicking your legs. Holding the edge of the pool, jump your feet from the bottom of the pool up onto the wall repeatedly. Many strength-building exercises that you can do on dry land are also possible in the water.
You can also do some simple leg-strengthening exercises from the comfort of your home. Take a peek at this list of the most common moves suitable for people of all ages:
- Squats – Stand with your feet shoulder-width apart. Bend at the knees, pushing your glutes backwards as if trying to sit on the edge of a chair. You should hold your body weight in your heels. As you return to a standing position, squeeze your buns at the top of the movement. You can place your feet wider or closer together to work different leg muscles.
- Lunges – Standing with your feet slightly apart, take one foot out in front of your body so that you’re standing with your legs in an open-scissor pattern. Bend both knees, taking your back knee toward the ground and maintaining a 90-degree angle with the front leg. Hold for a moment before rising back to a standing position and pushing your front leg off the ground to return to your starting position. Rotate legs. You can also walk while lunging each leg.
- Glute Raises – These are also called glute bridges. Rest on your back with knees bent and feet flat on the floor. Place your hands slightly under your glutes on each side, and then push your hips up. Your feet should plant firmly into the floor as your hips and glutes move straight up. Keep your shoulders and neck on the ground. Lower back to starting position and repeat. Try to squeeze your glutes before lowering to the floor each time.
- Step Ups – This is as simple as stepping up onto a raised platform. Rotate your lead leg with each step, squeezing your glutes a little as you pull your second leg up to the step. You can do this with an exercise step, the bottom step of a staircase, a bench or any other raised platform that is secure and at the right height to challenge you without presenting a safety concern. Start with low steps and work your way up to higher platforms with time.
With time, you can make these simple movements harder by adding jumps or holding weight. Simply increasing the number of repetitions in a set or the number of sets performed can challenge your legs with time as well. You may also want to learn some moves that combine your lower and upper body for maximum health benefits. For instance, try squatting and then raising your hands up over your head as you come back up to standing.
Simple calf raises while sitting on the couch or standing in line can help as well. Your calves are critical to longevity and cognitive health, but they also serve as the “second heart” and are critical to the health of your circulatory system.