How Women Should Adapt Their Training As They Age

Sims emphasises that this decade is about consciously moving away from just “going and doing a circuit.” Instead, women need to select heavy compound exercises (squats, deadlifts, presses, rows, chin‑ups) and progressively overload within structured 6‑week blocks. The goal is to create a robust musculoskeletal base that will be called upon later, when estrogen fluctuations in the 40s start increasing injury risk. By periodising, you also teach the nervous system to recruit high‑threshold motor units efficiently. This decade sets the stage for the power‑oriented work that becomes crucial for longevity later.

Sims frames this protocol as a non‑negotiable for women entering their 40s and 50s. Unlike the younger years, the goal is no longer hypertrophy but strength and neural resilience. She frequently sees women in perimenopause who suddenly can’t sleep, are gaining fat, and presenting with classic connective‑tissue injuries. By pre‑emptively shifting to heavy compound lifts with a few reps left in the tank, women can manage the increase in systemic inflammation and maintain metabolic rate. Adding sprint intervals provides a sharp CNS stimulus without the chronic stress of long, moderate‑intensity cardio. The inclusion of unilateral exercises (e.g., single‑leg deadlifts, single‑arm presses) is intentional; research shows they create greater cross‑brain activation, which may be especially neuroprotective during the hormonal transition. This entire approach is designed to “pre‑arm” the body so that the physiological stress of perimenopause does not result in injury or rapid functional decline.

Sims explains that when you’re younger, the hormonal milieu allows for effective muscle protein synthesis and hypertrophy from failure work. Once estrogen becomes erratic in perimenopause and lean mass gains are harder, the more important adaptation is neural. Heavy loads (not necessarily to failure) increase rate of force development, improve motor unit recruitment and synchronisation, and create robust neuromuscular connections. This feeds forward into better balance, coordination, and—from a longevity standpoint—may slow cognitive decline. She draws a direct line to Alzheimer’s and dementia sex differences, noting that strength and power‑based training yields neuroprotective effects through increased neural growth factors and pathway formation.

During perimenopause, ovulatory cycles become anovulatory, progesterone drops or disappears, and estradiol pulses flatten. Because every body system has estrogen receptors, this instability causes a spike in connective‑tissue injuries (frozen shoulder and plantar fasciitis are two classic presentations she sees). Sleep quality erodes and visceral fat accumulation accelerates. Sims therefore coaches women to enter this period already conditioned with heavy lifting and a polarised training model—hard days hard, easy days easy—rather than spending excessive time in Zone 2. The goal is to pre‑arm the CNS and musculoskeletal system so the body can tolerate the hormonal storm without injury or excessive compositional change.

Sims’ rationale is that during perimenopause the body is in a significant stress state due to fluctuating hormones. Heavy resistance work and true sprint‑interval sessions (very high intensity, short duration) drive beneficial neural and muscular adaptations, while excessive time in the moderate‑intensity “grey zone” can add chronic stress without sufficient recovery. By polarising—mixing maximal effort bouts with ample low‑intensity recovery—women can preserve lean mass, maintain metabolic rate, and strengthen neuromuscular connections. She also notes this approach helps condition the central nervous system to handle the abrupt physiological changes so that negative outcomes (injury, fat gain, sleep loss) are blunted.