Should Women in Menopause Still Do Zone 2? Cardio Choices For Metabolism and Insulin Control

Sims insists that sprint interval training is the antidote to the cultural message that women should avoid very high intensity exercise. She frames SIT as a necessary external stress that replaces the metabolic role of lost estrogen and progesterone, because it forces the body to create new feedback pathways. The assault bike is highlighted as ideal because it engages both arms and legs against air resistance, demanding total-body maximal output and allowing the user to track meters as a motivational tool. She describes a common gym scenario: people claim they can do 5–8 rounds, but after the second all-out sprint they are completely spent. This reality check is itself a teaching point—true SIT is unsustainable beyond a few repeats. The recovery period of 3–4 minutes is critical to allow phosphocreatine replenishment and to reset neural drive; otherwise the subsequent efforts become submaximal and lose the unique GLUT4 stimulus. The adaptation period of 3–4 weeks aligns with the time it takes for epigenetic changes to manifest at the protein level, offering a clear expectation for women to track progress.

Sims distinguishes HIIT from SIT by intensity and duration: HIIT sits at the 80–90% effort level and lasts 1–4 minutes, making it more sustainable than all-out sprints. She describes it as the next tier down, targeting mitochondrial biogenesis rather than the immediate GLUT4 epigenetic switch. This type of training is critical for women whose hormonal shift has increased their propensity to store fat viscerally. By enhancing the muscle’s ability to burn fat for energy, HIIT creates a metabolic environment where free fatty acids are cleared more efficiently. Sims stresses that the combination of SIT (insulin control) and HIIT (mitochondrial fat oxidation) is what delivers comprehensive metabolic health and body composition changes. Without HIIT, the visceral fat component may remain unaddressed. She also notes that this training must be sufficiently hard—‘above and beyond’ what the body is accustomed to—in order to elicit adaptation, because the former hormonal assist is no longer present.

Sims immediately counters the 'zone 2 rhetoric' when asked about cardio for menopausal women. She explains that female physiology differs: women don't require a large volume of Zone 2 to upregulate free fatty acid use or mitochondrial function. Instead, she frames Zone 2 as 'soul food'—pleasurable, mentally restorative, but not sufficient as a training stimulus for the 50-year-old body. She emphasizes that women trying to lose abdominal adiposity, improve insulin control, and change body composition cannot rely on long slow work alone. This is because the hard exercise stress that once came from estrogen, progesterone, and to some extent testosterone is now missing; external high-intensity stress must replace it to create new feedback pathways. She also cautions against prescribing multi-hour endurance rides to women who haven't been doing them, calling it 'contraindicated to what we want for the body.' Throughout, she draws on her own endurance background as both a participant and researcher, making her critique rooted in lived experience, not just theory.

Sims describes that during a true maximal sprint—30 seconds or less—the muscle experiences an epigenetic stimulus that upregulates the glucose transporter GLUT4. These proteins act as gates that move to the cell surface to usher glucose and carbohydrate inside, independent of insulin. Over approximately three to four weeks of consistent sprint work, the body adapts by increasing the number of these gates and their readiness to translocate. This means that less insulin is needed to handle a given glucose load, and skeletal muscle becomes more carbohydrate-sensitive. The adaptation essentially bypasses the insulin signaling pathway that often becomes blunted with age and hormonal decline. Sims presents this as a powerful, non-pharmacological strategy to restore metabolic control that was previously facilitated by estrogen and progesterone.