Practical guidance for improving healthspan and why it matters for women and weight loss medication users
Aging brings many changes, but one of the most overlooked is the gradual decline in muscle mass and strength. Starting in our 30s, we lose muscle at a rate of 3-5% per decade, with this loss accelerating in our 50s and 60s, leading to a cumulative decrease of up to 30-40% in muscle mass later in life. To make matters worse, most adults today spend more than 8.5 hours a day sitting—whether it’s in front of a screen or just lounging. The result? Accelerated muscle loss and a faster decline in physical function. But it doesn’t have to be this way. There’s a proactive way to take charge, and it’s as effective as Popeye’s spinach: resistance training and adequate protein intake are today’s essential combo for keeping your muscles strong and your healthspan long. This is how we stay sharp, strong, and resilient to chronic disease—yet many people aren’t doing what they need to stay in the game.
Muscle Loss: It’s More Than Just Aging
While everyone experiences muscle decline with age, women are especially vulnerable, particularly during and after menopause. This vulnerability is primarily due to the sharp drop in sex hormones like estrogen, which play a crucial role in regulating muscle and bone health. As women transition through their 40s and 50s, the loss of strength is often linked to a reduction in balance, especially in key muscle groups like the hip flexors and abductors. This imbalance significantly increases the risk of falls and fractures—especially hip fractures—which can severely diminish quality of life.
Research has shown that twice-weekly resistance training can boost muscle strength in postmenopausal women by up to 50%, emphasizing the powerful impact of such interventions. The conversation becomes even more critical with the growing use of GLP-1 medications, like Ozempic or Wegovy, for weight loss. These drugs can cause disproportionate muscle loss, with up to 40% of the weight lost coming from muscle rather than fat. For women on these medications, incorporating resistance exercise and ensuring adequate protein intake is essential to preserving muscle mass and maintaining overall health.
The Mechanisms Behind Muscle Loss
Having dedicated over 20 years to researching the underlying mechanisms that regulate muscle mass, I have focused my work at Harvard, the University of Nottingham, and the University of Exeter on how we can directly influence muscle maintenance and strength. These research programs have explored how nutrition and physical activity impact this metabolic cascade and help prevent muscle loss in both health and disease. At the molecular level, sarcopenia—the age-related loss of muscle—results from an imbalance between muscle protein synthesis (building new muscle) and muscle protein breakdown (losing existing muscle). This imbalance is often exacerbated by a decline in anabolic hormones, reduced physical activity, and changes in how our muscles respond to nutrients as we age. To put it simply: as we get older, our muscles become less responsive to the signals that typically tell them to grow or maintain themselves.
However, understanding these pathways gives us ways to fight back. One key player here is the PI3K/Akt signaling pathway, which is crucial for muscle growth. When this pathway is active, it triggers the mammalian target of rapamycin (mTOR)—think of mTOR as the body’s internal construction crew for building and repairing muscle. When mTOR is switched on, it ramps up the production of new proteins that strengthen and repair muscle fibers.
On the flip side, aging also activates proteins like FOXO, which leads to muscle breakdown. FOXO increases the expression of markers like Atrogin-1 and MuRF-1, which tag muscle proteins for breakdown in a process called the ubiquitin-proteasome system—the body’s way of clearing out old or damaged proteins. During my PhD and postdoctoral work, I focused on how the balance between these pathways shifts in health and disease. As mTOR’s influence wanes and FOXO’s activity increases, we see a greater loss of muscle. Understanding these processes not only reveals why muscle loss happens but also highlights why resistance training and adequate protein intake can be so effective: they help tip the scales back toward muscle-building by stimulating mTOR and reducing the activity of muscle-wasting pathways.
(Illustration: Prof Nima)
Why Muscle Matters
Muscle mass isn’t just about aesthetics—it’s central to your metabolic health, mobility, and cognitive function. You might not notice it yet, but by the time you’re in your 60s or 70s, the cumulative loss of muscle can leave you feeling weaker, slower, and more vulnerable to injury. Yet, with a little focus on resistance training, you can significantly reduce these risks. Resistance training has been shown to counteract the effects of sarcopenia (age-related muscle loss), enhance bone density, and improve overall quality of life. A study from Maastricht University even showed that with proper strength training and protein intake, elderly individuals can still gain muscle—proving that it’s never too late to start.
Resistance Training: Your Key to Strength and Longevity
The magic of resistance training is that it taps into the body’s natural anabolic processes—essentially telling your muscles, “Hey, we still need you!” Whether you’re 25 or 65, this signal remains effective. Studies recommend at least 3-4 sessions of resistance training per week, focusing on varied exercises like squats, lunges, and deadlifts that target multiple muscle groups.
For women, especially around menopause, focusing on lower-body exercises is key. Strengthening muscles in the hips, legs, and core can improve balance and prevent injuries. If you're someone who doesn't like the idea of a gym full of weights, no worries—resistance bands and bodyweight exercises can offer the same benefits. Studies even show that low-impact, resistance band exercises performed at home can increase muscle strength and mass in women as effectively as traditional gym workouts. This makes resistance bands a fantastic option for accessibility and effectiveness.
Protein: The Essential Building Block
When it comes to muscle health, protein is as important as exercise. Yet, the current RDA of 0.8 grams per kilogram of body weight falls short of what’s needed to stave off muscle loss. Emerging research, including work from my colleagues, indicates that older adults should aim for 1.2 to 1.6 grams per kilogram per day to optimize muscle protein synthesis. But more than just the total amount, how you spread your protein intake matters. Aiming for 0.3 grams per kilogram per meal can help maximize muscle-building throughout the day. For a person weighing 70 kilograms (about 154 pounds), this means targeting around 20 grams of protein per meal—roughly the protein content in a tuna sandwich or a three-egg omelet. This approach helps ensure that each meal provides the right signals for muscle synthesis, keeping you strong as you age.
To get the most out of your protein, aim to eat regularly spaced meals and snacks, every three to five hours. This timing helps maintain a steady supply of amino acids to your muscles, which is especially beneficial for older adults experiencing anabolic resistance. And while protein powders can help fill in the gaps, focusing on real food sources—like eggs, high protein yogurts, and lean meats—provides a broader range of nutrients. Remember, it’s not just about the protein: meeting your overall daily energy and macronutrient needs is crucial for sustaining muscle health.
Practical Steps for Better Muscle Health
So how do you take all this information and turn it into action? Here are some practical takeaways:
- Resistance Training: Aim for 3-4 sessions per week that include full-body, compound exercises like squats, lunges, deadlifts, and presses. If you’re new to weightlifting, start with resistance bands or bodyweight exercises.
- Balance and Flexibility: Add exercises that enhance stability, particularly if you’re over 40. Yoga or Pilates sessions can improve core strength and balance, reducing your risk of injury.
- Cardiovascular Exercise: Pair your strength training with 150-200 minutes of moderate-intensity cardio per week. Walking, running, cycling, or swimming are great options.
- Protein: Aim for 0.3 grams per kilogram of body weight per meal, spread evenly across the day. For a 70 kg person, this means targeting around 20-25 grams of protein per meal, with total daily intake between 84-112 grams.
Tracking tools and dietary planning apps can be helpful for logging your meals and checking if you’re hitting your protein targets consistently. For those taking GLP-1 weight loss medications, it’s even more important to focus on muscle preservation. By combining resistance training with increased protein intake, you can mitigate the muscle loss that often accompanies these treatments.
The Bottom Line: Take Control of Your Aging
Aging doesn’t have to mean becoming weaker. By incorporating resistance training, increasing protein intake, and being proactive about muscle health, you can extend your healthspan and live not just longer, but stronger. This isn’t just about preventing frailty—it’s about maintaining independence, vitality, and quality of life well into old age. So remember to take your spinach: move, lift, eat, and repeat. The science is clear—muscle health is your key to thriving as you age.