Notes on Dr. Stacy Sims' book Next Level

My wife recommended this book, and a few clients had brought up Dr. Stacy Sims’ work as well. Some of what I found inside was different than I expected, so I decided to dig in. After studying the book carefully, it became clear how strongly the physiology of menopause aligns with the type of training we emphasize—but there are also very specific considerations about hormonal changes that deserve real attention.

One of the biggest takeaways is that much of the exercise science we rely on has historically been based on research in men. Women—especially peri- and post-menopausal women—have distinct needs that change how they should train, eat, and recover. These notes summarize the key points from Next Level for anyone who might find them useful.

Note: Dr. Stacy Sims has faced a lot of scrutiny from researchers regarding her claims of training fed vs. fasted and meal timing as well as lifting heavy vs. lifting moderately heavy. Long-term randomized control trials don't appear to exist in these categories. In my perspective, Stacy is pushing the conversation and driving debate. It is really a new area of research which I think is greatly needed.

Hormones & Definitions

Anabolic: building tissue (muscle, bone, organs)

Catabolic: breaking down tissue

Sympathetic nervous system: fight or flight, high stress

Parasympathetic nervous system: rest and digest, recovery

Estrogens

• E1 – Estrone: weaker estrogen; becomes the dominant estrogen after menopause because it is produced in fat tissue.

• E2 – Estradiol: the strongest and most biologically active estrogen. It is:

  • Anabolic (supports muscle & bone)

  • Increases insulin sensitivity

  • Helps regulate appetite

  • Directly supports muscle contractile proteins (myosin)

  • Supports mitochondrial function (aerobic metabolism)

  • Enhances serotonin (mood)

  • Helps regulate body temperature & vasodilation

  • Supports bone formation

  • Increases joint laxity (looser connective tissues)

• E3 – Estriol: mainly present in pregnancy.

Progesterone

• More catabolic

• Counterbalances estrogen

• Raises core body temperature

• Can reduce neuromuscular coordination and increase fatigue

• Has anti-anxiety effects and increases BDNF

• Increases pain tolerance

• Suppresses immune response (to protect a potential embryo)

Cycle context (premenopause):

• Estradiol (E2) peaks around week 2.

• Progesterone peaks around weeks 3–4.

The Menopausal Cascade

When E2 and progesterone decline:

Effects of Low Estradiol (E2)

• Less anabolic → less muscle & bone, slower recovery

• Lower insulin sensitivity → easier fat gain

• Increased appetite

• Lower mood (less serotonin)

• More fatigue

• Higher blood pressure

• Higher cardiometabolic disease risk

• Less stable thermoregulation (hot flashes, night sweats)

• More joint discomfort due to changes in collagen structure

Effects of Relative Estrone (E1) Dominance

• Since total estrogen drops, E1 becomes the primary form

• Produced in fat tissue → often associated with increased abdominal fat

• Associated with higher cortisol

• Higher cortisol → more fat storage & worse sleep

Combined Low E2 + Low Progesterone

• Increased systemic inflammation

• Gut disruption

• Higher hepcidin → greater risk of anemia

• ~25% lower pain tolerance

• Lower HRV and impaired recovery

• Temperature instability

Progesterone loss specifically

• Mood swings

• Memory issues, brain fog

• Lower pain tolerance

• Bone loss

• Worsened sleep (due to loss of temperature regulation)

Gut Health

Why gut health matters: Mental health, body composition, bone density, nutrient absorption, sleep, antioxidant production, mitochondrial function, inflammation control, ATP production, lactate clearance.

Firmicutes vs Bacteroidetes  

• Firmicutes: more efficient calorie extraction; often higher in obesity

• Bacteroidetes: often higher in lean people

• A higher Firmicutes:Bacteroidetes ratio is associated with obesity, but not deterministic. It affects calorie extraction efficiency and inflammation—but it doesn’t override energy balance entirely.

Microbiome affects:

• Inflammation

• Hormone metabolism (the estrobolome)

• Nutrient absorption efficiency, again it does not override energy balance entirely.

Improve the ratio (and gut health in general):

• Eat fiber-rich fruits & vegetables

• Target 25 g fiber/day

• Legumes, nuts, seeds

• Coffee

• Fermented foods (probiotics)

• Prebiotics: garlic, onions, leeks, asparagus

• A healthier microbiome helps metabolize estrogen more effectively, easing symptoms.

Conclusion:Healthy food → healthier gut → better menopause outcomes.

Training Guidelines (Core of the Book)

Don’t train fasted (note: it appears longitudinal studies don't quite support this and her claim is hotly contested. It is better to exercise than not to. I would not let meal timing get in the way.)

Women respond poorly to fasted training in peri/menopause because:

• Higher cortisol

• Lower blood glucose stability

• More muscle breakdown

• Worse adaptations

Eat protein + carbs before and after training.

The Core Idea: Replace What Estradiol Used to Do

Lift Heavy

Muscle is metabolic currency. Menopause accelerates the loss of both muscle and bone—bone density can decline by up to 20% during the transition.

Light weights for high reps do not produce a strong anabolic signal. Long, steady cardio combined with low calories increases cortisol and often leads to muscle loss, fat gain, and worsening symptoms. (Note: The key here is training close to failure. Lighter weights are inefficient.)

Strength training appears to be far more effective than endurance training for improving body composition and health outcomes in menopausal women. (Good long-term study data here.)

And it improves immune function → fewer sick days.

Energy Intake: Why You MUST Eat Enough

Under-eating in menopause causes:

• Higher cortisol

• Thyroid downregulation

• Lower metabolic rate

• Muscle + bone breakdown

• Increased fat storage (body goes into “protective mode”)

To lose fat:

• Maintain adequate fueling around workouts

• Maintain sufficient total calories

• Use brief, intense training to create a metabolic shift

• Avoid chronic, large deficits

Stacy says Women need to refuel within ~30 minutes post-exercise. Men have a longer window (~90 minutes). (Note: this is has generated a lot of debate and long-term studies are hard to find.)

The key goal: maximize lean mass to drive metabolic rate, energy, strength, and symptom control.

Macronutrients Example (Active 130 lb / ~59 kg Woman)

• Carbs: 3 g/kg → 177 g → 708 kcal

• Protein: 2.2 g/kg → 130 g → 520 kcal

• Fat: 1.2 g/kg → 71 g → 639 kcalTotal ≈ 1,867 kcal/day

This feels high only because many women are taught to eat ~1,200 kcal — which is drastically under-fueling and metabolically harmful.

Training Prescription (What EverStrongSF Already Does)

• Lift heavy → strong anabolic signal, lowers cortisol, builds muscle, improves mood & sleep

• Low volume + high intensity → reduces catabolic load

• Eat protein + carbs pre- and post-training (again: a lot of debate on this)

• Build core strength → helps with pelvic floor issues

Why Brief High-Intensity Strength & Sprint Interval Training Work Best

With low estrogen:

• You burn less fat at rest

• Store more abdominal fat

• Have blunted anabolic signaling

Strength + Sprint Interval Training (CAROL bike, etc.) is medicine:

• Burns circulating glucose (E2 normally helps do this)

• Provides a strong anabolic stimulus

• Improves insulin sensitivity

• Reduces visceral fat

• Increases VO₂ max

• Improves cardiac stroke volume

• Lowers resting heart rate

• Improves thermoregulation (vasodilation)

• Improves blood pressure control

• Reduces cortisol over time

• Supports bone density and connective tissue remodeling

Long, steady endurance cardio absolutely improves cardiovascular health. However, when menopausal women rely mostly on long cardio—especially while under-eating—it can drive up stress hormones, contribute to muscle loss, and be less effective for improving body composition than a combination of heavy strength training, sprint intervals, and proper fueling.

Supplements considered

Beta-alanine

• Helps with high-intensity efforts (buffering)

• May help women tolerate hard intervals better

• Not a direct “hot flash cure,” but can reduce exercise discomfort

Ashwagandha

• 250 mg can reduce stress/cortisol

• Not for people with thyroid issues

• Not for men with hormone-sensitive prostate cancer

Holy Basil

• 500 mg, twice daily

• Stress reduction

Rhodiola

• 150 mg

• Helps with cognition & fatigue

• Avoid with MAOIs, low BP, or late in the day

• Avoid if you have estrogen-driven cancers

Schisandra

• Stimulant/adaptogen

• Check the dose — the original “13.5 g/kg” is almost certainly a misprint

• Avoid late in day

Maca

• Performance/mood stimulant

• 2.5–3 g

• Not known to be WADA banned (a common misconception), but all supplements carry contamination risk

• Avoid with thyroid issues

Interesting Research Note

Women with high muscle mass + high fat mass had a ~42% lower risk of heart-disease–related death compared to women with low muscle + low fat.

In other words: Muscle matters more than leanness.