Why Muscle Mass Is a Longevity Marker: What Happens When You Lose It

Sims dismisses the debate over compound vs. isolated movements by stating that consistency trumps all. She advises that even when you're not pushing heavy loads—such as during a planned deload—you should still go to the gym at your usual time and use that session to refine technique and work on mobility. This keeps the habit ingrained and prevents the stop-start pattern that leads to detraining. The underlying principle is that adherence is the foundation of any successful training program, and the best program is the one you'll actually do.

Sims notes that as estrogen declines during perimenopause, women experience more soft tissue and joint injuries. Traditional heavy compound lifting can exacerbate this, leading to setbacks. By adding isometric holds—pausing and holding at the hardest part of a movement—women can still challenge their muscles effectively while using lighter weights. This approach helps maintain strength and muscle mass without the inflammatory response that often sidelines older female athletes. She emphasizes that this is a nuanced addition to a consistent training routine, not a wholesale replacement of dynamic exercises.

Sims shares her personal protocol after a knee injury: she used EMS, BFR, and increased her protein and omega-3 intake. She acknowledges that despite these efforts, she still lost lean mass, underscoring how challenging it is to preserve muscle in your late 40s. However, she believes these tools are essential to minimize losses. She notes that strength can be regained relatively quickly once training resumes, but the actual muscle tissue takes much longer to rebuild, so the priority is to hold onto as much lean mass as possible during the recovery period. This multi-pronged approach is what she recommends to her clients and uses herself.

Sims warns that the enthusiasm for GLP-1 drugs must be tempered by the reality of muscle loss. In her practice, they use microdoses for longevity in select patients but always pair this with DEXA scans to track body composition. She argues that losing lean mass is trading one risk factor (e.g., obesity) for another that is 'probably more powerful'—low muscle mass. The DEXA scan provides objective data to adjust dosing or add interventions to protect muscle. This protocol reflects a harm-reduction approach in the emerging field of pharmaceutical longevity.

Sims mentions that her clinic sometimes uses microdoses of these drugs for longevity purposes, but only in carefully selected patients. The idea is to harness the metabolic benefits without the extreme weight loss seen at higher doses. Still, she emphasizes that any use must be accompanied by body composition monitoring because the loss of lean mass could negate the longevity gains. This is a cutting-edge, off-label application that she approaches with caution.

Sims explains that as women enter perimenopause, they experience more soft tissue and joint injuries. To continue training effectively without setbacks, she recommends complementing lighter compound movements with isometric holds. This approach allows women to get more out of each movement—enhancing muscle activation and time under tension—while avoiding the inflammation that can come from heavier loads or high-rep isolation work. She stresses that even during a scheduled deload week, maintaining the habit of going to the gym at the same time to work on technique and mobility is key to long-term consistency. The overarching message is that adherence trumps exercise selection, but smart modifications can keep women training pain-free through hormonal transitions.

Sims recounts sustaining a torn meniscus and distal hamstring tear in February, which made preserving muscle extremely challenging. She turned to a combination of electrical muscle stimulation (EMS), blood flow restriction (BFR) training, and increased dietary protein and omega-3 fatty acids. Despite these efforts, she still lost a significant amount of lean mass, though her strength remained relatively intact. She notes that in your late 40s and early 50s, building lean mass is particularly difficult, so the priority is to hold onto what you have. She advocates for using all available tools—EMS, BFR, nutrition—to maintain lean mass during injury recovery, because strength can be regained more quickly than the actual muscle tissue. This experience underscores her broader message that lean mass is a precious, hard-won asset that requires proactive protection.

Sims explains that for certain high-risk patients, her clinic sometimes uses very low doses of GLP-1 agonists (like Ozempic, tirzepatide, Wegovy) as a longevity intervention. However, they always screen patients with DEXA scans to monitor lean mass because these drugs can cause significant muscle loss. She warns that we may be trading one longevity risk factor (e.g., obesity, insulin resistance) for another that is arguably more powerful: low muscle mass. She reinforces this by citing a study from her critical care days: patients without optimal muscle mass upon entering the ICU have double the risk of death, regardless of the reason for admission. This makes preserving lean mass a non-negotiable priority, and any intervention that threatens it must be carefully managed.