Humans Age Dramatically At 2 Key Life Points, New Research Suggests
Fortunately, there are evidence-backed secrets to maintaining vitality.
elenaleonova | Canva We tend to think of aging as linear - like sands falling through an hourglass or hands moving around a clock face. Each morning, we wake up a day older. Each birthday, we add one more candle to the cake.
But science is proving that aging isn't all that simple. Rather than being a slow and steady process, new research from Stanford University’s School of Medicine points to two major waves of chemical processes that occur in accelerated bursts.
"We're not just changing gradually over time," Michael Snyder, PhD, a geneticist at Stanford University and senior author of the study, said in a statement.
New research suggests that the mid-40s is a time of dramatic change, as is the early 60s.
For most functions, Snyder and his team found, the drama unfolds differently at different ages. For example, 40-somethings undergo a significantly decreased ability to metabolize alcohol, while 60-somethings experience a decreased ability to metabolize carbohydrates. The study was published this month in Nature Aging.
However, there was one change researchers noted that affected people at both age points: A dramatic decline in muscle mass. A 2023 Metabolism Journal review found that this decrease can lead to a serious condition known as sarcopenia, which is associated with a high risk of a wide range of adverse health outcomes - including metabolic disorders such as Type 2 diabetes, cognitive impairment, falls, and fractures, and the big one: death.
The good news is that even if you've already lost some muscle mass, it doesn’t mean it’s gone forever. As Ryan Carver, a certified strength and conditioning specialist and author of The Longevity Lifestyle: Your Guide To Aging In Reverse, told me, "It's never too late to rebuild muscle and maintain it."
Prostock-studio | Shutterstock
The problem with less muscle mass
Starting in their late-40s to mid-50s, most people can expect to lose about one pound of muscle a year, Carver said. While that may not seem like a lot, consider that for a 140-pound person, that adds up to a loss of more than 7% of total muscle mass.
And it gets worse: Once you reach your mid-60s, that rate of muscle loss doubles. Now, you're losing about two pounds of muscle each year. A 2019 Journal of Strength and Conditioning Research study found that this decrease mostly affects your fast-twitch muscle fibers - the type built for short, powerful bursts of energy. Fast-twitch muscle fibers are also what help you avoid the types of falls that send you to the ER or nursing home.
Less muscle mass means greater weakness and less mobility. You appear frail to family and friends. It's hard to get out of a chair, walk briskly, maintain your balance, lift heavy objects, and open jars.
Worse yet, neglecting to combat loss of muscle can take your life. If you're inactive and let nature take its course, your muscles will decline to the point that it can impair your physical and emotional well-being. It may be difficult to carry out the basic tasks of daily life.
Lordn | Shutterstock
The proven way to rebuild muscle
To keep frailty at bay, a plan of action is needed. Carver said many people mistakenly believe pharmaceuticals, vaccines, or supplements can prevent or reverse sarcopenia. Not so. And while good nutrition is always a good idea, Carver said, no evidence eating well prevents or reverses age-related muscle loss.
Not even physical activity can stave off sarcopenia. Of course, activities such as walking, gardening, and hiking are good for you, but they can’t prevent muscle loss.
So what’s the answer? As Carver points out, to significantly improve muscle quality, research from a 2012 American College of Sports Medicine study confirms the superior benefits of lifting weights. If you build muscle with strength training, it slows bone loss and triggers new growth. You not only get stronger muscles but also denser bones. Together, they stabilize your joints so you’re less likely to become injured.
Carver recommends lifting weights through power training - which coaches you to move explosively. Power training activates those fast-twitch muscles that help you do everything from reacting safely while driving, to staying out of the emergency room after a fall.
Lordn | Shutterstock
The keys to successful power training
Don’t worry — to power train, you don’t have to lift the same amount you did as a buff 20-something. You simply need to work at an adequate intensity. To make the most of your sessions, Carver suggests:
- Overload progressively. This means you’re constantly challenging yourself. Consider adding more repetitions, adding more weights, or adding more sets. "Your muscles require metabolic signaling pathways," Carver said. "If you're working at a sub-optimal intensity, you never reach the critical threshold that tells your body to build more muscle."
- Be consistent. Success doesn’t come from what you do occasionally; it comes from what you do regularly. In a 2011 position paper, the American College of Sports Medicine details the health benefits of consistent exercise. These perks include decreasing the risk of cardiovascular disease, Type 2 diabetes, stroke, and some types of cancer. Schedule exercise sessions three to four times each week.
- Pay attention. Carver sees many clients who treat exercise like a task to check off their to-do list. But lifting weights requires focus. To elicit optimal muscle growth and accelerate your results, focus on increasing the tension in your muscles.
- Seek out expertise. Get a lesson from a nationally accredited certified personal trainer. Consider treating exercise like a prescription. Get help from an expert to be sure you get the dosage, frequency, duration, and intensity right.
Stanford University scientists say their study points to the need for people to maintain attention on their health, especially in their 40s and 60s. "I'm a big believer that we should try to adjust our lifestyles while we’re still healthy," senior study author Snyder said.
As fitness coach Carver put it, "Aging is like being thrown into the ocean. If you stop treading water at any point, you'll drown - into a stooped-over, shuffling person."
Kathleen Murphy is a longtime writer and frequent contributor to Medium.com, where she specializes in physical health, emotional wellness, and successful aging.