How should aging female athletes fuel and train to improve performance and body composition?

Let’s do a deep dive into Dr. Stacy Sims interviews and blogs.

Dr. Stacy Sims on MBG podcast Summary

Dr. Stacy Sims on Peri-Menopause:

The changing ratio of estrogen and progesterone affects all systems in the body, including the microbiome, recovery, body composition, brain function, neurotransmitters, and sleep architecture.
Hormonal shifts mean it’s now essential to find external stressors that trigger adaptation, similar to how hormones previously supported the body.
Focus on polarized training: high-intensity workouts and heavy lifting, while reducing volume and ensuring adequate recovery.
Create a stimulus to boost growth hormone production.
Epigenetic changes in muscle support better blood glucose control and glucose homeostasis.
Signals from the central nervous system help maintain power, speed, and lean muscle mass.

Dr. Stacy Sims on Post-Menopause:

Early Post-Menopause (5-6 years after menopause):
- Prioritize heavy lifting and sprint interval training (SIT) 2-3 times per week.
- Reduce lower-intensity, high-volume exercise—less is more.
Late Post-Menopause (6+ years after menopause):
- The body no longer responds as well to high-intensity work.
- Adapt with shorter, regular doses of sprint intervals rather than increasing volume. For example, incorporate 4 days of 15-minute SIT sessions.
- Without estrogen and progesterone receptors, maintaining lean mass, vascular and bone strength, cognition, and proprioception becomes more challenging.
- Early post-menopause allows for more play in training, but later stages require daily short bursts of SIT (e.g., 4 x 20-second sprints instead of longer intervals).

Sprint Interval Training (SIT):

SIT promotes fast muscle contraction and neural pathway activation, which supports cognition and fast-twitch muscle function.
Utilizes glycolytic fuel (ATP, CP, carbohydrates) for energy.
Increases GLUT4 transporters, which help glucose enter the cells without relying on insulin, vital for maintaining glucose homeostasis as insulin resistance increases with age.
Reduces deep abdominal fat through exerkine signaling between muscle and fat tissues.
Improves proprioception, reducing fall risk.
Avoid long slow distance endurance training—focus on RPE 9/10 efforts for no more than 30 seconds, followed by recovery in Zone 1.

Training for Women vs. Men:

Research is predominantly based on male studies, but women inherently have more slow-twitch muscle fibers and greater mitochondrial density, making them more efficient at fat oxidation and lactate recycling for aerobic metabolism.
Women benefit from Zone 2 training for mitochondrial health, oxidative capacity, and increased MCT1 transport proteins, which remove lactate from circulation and repurpose it as fuel.
However, women have fewer fast-twitch muscle fibers than men and require more high-intensity work (like HIIT) to stimulate lactate production and clearance.
Women should focus less on long slow distance (Zone 2) training, as it can lead to stagnation in progress, whereas men generally benefit more from Zone 2 for increasing mitochondrial respiratory capacity and slow-twitch muscle fiber health.
High-intensity training in women helps upregulate MCT1, essential for lactate production, clearance, and optimal performance.

The WHOLE Athlete Lavaman Training Program 2020

Dr. Stacy Sims on PERI-MENOPAUSE:

Changes in ratio of Estrogen and Progesterone impacts all systems of the body

Microbiome changes

Recovery

Body Composition

Brain +Neurotransmitters

Sleep architechture

Hormones changing – now I need to find an external stress that is going to cause an ADAPTATION the way the hormones used to support

Polarize high intensity training and heavy lifting

Dropping the volume and adequate recovery

Creating a stress to stimulate growth hormone

Epigenetic changes in muscle to help with blood glucose control and glucose homeostasis

Signal central nervous system to maintain power, speed and lean mass

Dr. Stacy Sims on POST MENOPAUSE:

Early menopause – 5 to 6 years after the one day in time of MENOPAUSE

Lift heavy

Sprint interval training 2-3 x week

Limit or decrease lower intensity exercise with high volume (less is more)

Late menopause- 6 years after the one day in time MENOPAUSE

We don’t respond as well to the high intensity work

Solution – more regular doses of sprint intervals but not more volume- shorter doses

SIT 4 days of 15 minute intervals

We lost sensitivity to estrogen or progesterone without the receptors around

To keep lean mass, blood pressure in check, vascular, bone strength, cognition, and proprioception

More play early post menopause but later post menopause we need to do SIT daily but short dose.

more; regular, shorter doses of SPRINM interval training as we have lost sensitivity and loss of receptors

Example 4 x 20 second sprints instead of 10 … upper intensity focus

Sprint Interval Training

Central nervous system response – fast muscle contraction, neural pathways and avoid cognitive decline

Glycolytic fuel- ATP CP and carbohydrate use for fueling

More GLUT4 transporters- gate to allow glucose to come into cell without insulin = maintain glucose homeostasis as we are more insulin resistant as we age

Cross talk with exerkines – deep abdominal fat and skeletal muscle via messengers – need carb in the muscle and not deep ab fat

Proprioception – fall risk decreases

Not the long slow distance endurance training

Push RPE 9/10 and no more than 30 seconds, recovery back to Zone 1

Fast Twitch muscle fibers

Zone Two for women?

Research is based on male studies

Women already have a larger amount of slow twitch fiber- oxidize fat better

Women have less fast twitch muscle fibers than men

Born XX – greater mitochondria density, mitochondrial respiration and greater sensitivity to metabolites that inhibits free fatty acids that come into cell

Women are already very good at taking lactate, recycling it to use as fuel in aerobic metabolism

Benefits of ZONE TWO– mitochondria health, increasing oxidative capacity, increasing mitochondrial health, increasing the number of MCT1 Transport Proteins

MCT1 Transport proteins take lactate out of circulation then put them into mitochondria to get the lactate into circulation and be used as fuel

MEN do need to increase the MCT1 to increase mitochondria health, mitochondrial respiratory capacity and slow twitch muscle fiber

MCT1 – put lactate into circulation and out to use as fuel

Men don’t have the same response as women do = difference between the exercise intensity = women need to do more high intensity work as they have less glycolytic muscles = we need to stimulate lactate production and regulate the ability to produce it then clear it

if women don’t improve by doing sprint training -and spend too much time in Zone 2 ‘long slow distance’ – stuck being slow

Men need more Zone Two training than women

The exercise intensity – women need more HIIT as less glycolytic muscles or stuck in slow pace

Sprint work and HIIT in women vs. men = women upregulate more MC1

The exercise intensities- women need more HIGH intensity to stimulate lactate, to produce it and clear it …less SLOW MO workouts than what men need

Women need to change how they fuel and train to get their desired improvements

Dr. Stacy Sims on Women and Zone 2 Summary Notes

Zone 2 training is often promoted as a low-intensity, steady exercise (60-70% max heart rate) beneficial for endurance and metabolic health, but its benefits are overstated for women.
Women naturally have a higher proportion of Type 1 slow-twitch fibers, which are efficient at fat oxidation and have higher mitochondrial density compared to men. This means women already excel at using fat as fuel during exercise.
Metabolic flexibility—the ability to switch between fat and carbohydrate for energy—is also naturally higher in women, making additional Zone 2 training less critical for improving this aspect.
Women store more intramuscular fat and have better fat metabolism due to higher levels of fat transporter proteins (CD36) and greater sensitivity to metabolic inhibitors like malonyl-CoA, making them less dependent on carbohydrate during exercise.
Lactate production and clearance: Women produce less lactate during exercise compared to men, who rely more on Type 2 fibers and carbohydrate metabolism. Men upregulate lactate transporter proteins (MCT-1) more, but women’s bodies don’t require the same adaptations due to lower glycolytic activity.
While Zone 2 training can be useful for active recovery, base-building, and lower-intensity days, women benefit more from high-intensity interval training (HIIT) or sprint work to stimulate mitochondrial and metabolic adaptations.
A key problem for women is often training in a “gray zone” that’s harder than true Zone 2 but not intense enough for real gains, leading to fatigue without performance improvement.
For women, focusing too much on long, steady-state exercise can result in being “stuck slow”. High-intensity sessions are more effective for stimulating lactate clearance, maintaining lean muscle mass, and enhancing performance.
When doing Zone 2, women should ensure it’s truly easy and conversational, avoiding the tendency to work harder than necessary.
https://www.drstacysims.com/blog/what-women-need-to-know-about-zone-2-training

Dr. Stacy Sims Summary on Training

Zone 2 Training Isn’t the Same for Women: Here’s a Better Approach

In one of her blogs, she broke down why Zone 2 training—touted online as the go-to for health, longevity, and performance—doesn’t benefit women the same way it does men. Let’s now explore what type of training actually works best for women.

A Quick Recap:

Zone 2 involves relatively easy, prolonged exercise (60-70% max heart rate for 45+ minutes) that feels sustainable for hours. The popular recommendation is to focus 3-4 weekly sessions on Zone 2 to enhance mitochondrial function, fat metabolism, and metabolic flexibility, while improving lactate clearance during higher-intensity exercise.

However, as discussed previously, prioritizing Zone 2 training may not be the ideal way for women to optimize mitochondrial function or lactate clearance. In fact, research suggests a different approach to training intensity is more effective for women.

The Science Behind It: MCT1 and MCT4

MCTs (MonoCarboxylate Transporters) are proteins that shuttle lactate and pyruvate across cell membranes. During intense exercise, skeletal muscles produce lactate, which isn’t just waste—it’s a fuel source that can be used by muscle and heart mitochondria. MCT1 pulls lactate into cells, while MCT4 moves it out of cells.

Research shows that exercise intensity impacts the expression of MCT1 and MCT4, but the response differs between men and women.

In men, MCT1 increases regardless of exercise intensity, and MCT4 increases with repeated sprint intervals.
In women, low-intensity training shows minimal increases in either transporter, but sprint interval training (SIT) increases MCT1 expression more effectively than lower-intensity exercise.

This difference is likely due to the lower glycolytic capacity in women compared to men and the influence of estrogen on MCT1 expression.

What Should Women Focus On?

For health and longevity, the goal should be to improve both mitochondrial function and glycolytic capacity, which supports brain resilience and may help prevent cognitive decline. Research indicates that at least three days a week of high-intensity interval training (HIIT) or sprint interval training (SIT) significantly increases MCT1 expression and enhances brain glycolysis, promoting better cognition and potentially preventing Alzheimer’s disease.

From a performance perspective, HIIT and SIT are crucial for boosting lactate production and clearance, while also building fast-twitch Type II fibers—which women have fewer of compared to slow-twitch Type I fibers. This translates to increased power and speed.

What About Endurance Athletes?

If you’re an endurance athlete, you still need long, slow training to build the capacity for long-distance events. However, spending too much time in Zone 2 won’t improve mitochondrial function and oxidative capacity in women the same way it does for men.

Interestingly, research has shown that while men need long, slow aerobic work to improve mitochondrial function, women naturally have better mitochondrial density and respiration. By integrating high-intensity work into your long training sessions, you can enhance both mitochondrial capacity and anaerobic capacity.

Conclusion:

If you’re not an endurance athlete, don’t be misled by the hype around Zone 2 training. Just because it’s trending doesn’t mean it’s the best approach for everyone—especially women. This highlights the importance of recognizing that women are not simply smaller versions of men, and training strategies should be tailored accordingly.

By mixing in specific high-intensity work, women can maximize their training benefits in a way that better suits their physiology.

What about carbohydrates? Summary…

Want to Avoid Low Energy Availability (LEA) and Relative Energy Deficiency in Sport (RED-S)? Eat Enough Carbohydrates

As fasting, keto, and carb-restriction gain popularity on social media, we’re seeing a troubling rise in low energy availability (LEA) among athletes. In my experience, around 55% of individuals who train daily fall into LEA, with women being particularly vulnerable.

What is LEA? LEA occurs when you’re not eating enough to cover both your basic metabolic needs and the energy you expend during exercise. If left unchecked, it can lead to serious health issues, such as a dangerous drop in bone mineral density.

How to Calculate Energy Availability (EA): To avoid LEA, ensure you’re eating enough to maintain energy availability (EA). EA is calculated as: Dietary Energy Intake (kcal) – Exercise Energy Expenditure (kcal), divided by Fat-Free Mass (FFM) in kilograms (kg).

Aim for an EA of 45+ kcal/kg of FFM. If you train regularly, 50 kcal/kg of FFM is a great target.

An EA of less than 30 kcal/kg is classified as LEA, and health risks can begin after just five days.

However, beyond just total calorie intake, it’s crucial to focus on carbohydrate consumption, particularly for women.

The Importance of Carbohydrate Intake

Current research highlights that many athletes, especially women, aren’t consuming enough carbohydrates. This creates low carbohydrate availability (LCA), which exacerbates the health and performance issues caused by LEA.

What is Low Carbohydrate Availability (LCA)? LCA occurs when your body doesn’t get enough carbohydrates to meet energy demands during exercise. The International Society of Sports Nutrition’s Female Athlete Position Stand emphasizes that consuming enough carbohydrates is essential to prevent LEA.

Endurance athletes need 4.5 to 7 grams of carbs per kilogram of body weight per day.

Women doing moderate training or short, intense sessions (e.g., CrossFit) require 3.5 to 5 grams of carbs per kilogram of body weight daily.

Yet, research shows that many women fall short of these recommendations. A study found that nearly half of young female athletes and a third of elite female athletes consume less than 4 g/kg of carbs per day. Across various sports, 45 to 98% of female athletes may not be meeting their carbohydrate needs.

Why Women are Particularly Sensitive to Low Carbohydrate Intake

Women are more sensitive to low nutrition, especially carbohydrates. When carbohydrate intake is insufficient, it reduces the expression of kisspeptin, a neuropeptide that regulates sex hormones and reproductive function. Kisspeptin also plays a role in glucose regulation, appetite control, and body composition.

Low kisspeptin levels can:

Increase appetite

Decrease energy expenditure

Lower glucose-stimulated insulin secretion

Prolonged LCA can lead to numerous performance and health issues, including:

Decreased endurance and muscle strength

Impaired glycogen stores

Poor concentration and coordination

Increased injury risk

Depression and irritability

For those trying to build lean muscle or improve sprint performance, LCA also hinders the body’s ability to make necessary adaptations, largely by increasing the oxidation of branched-chain amino acids (BCAAs), which are crucial for muscle growth and repair.

How to Prevent LCA and Maintain Optimal Energy Availability

1. Fuel for the Work Required:
Ensure you consume enough carbohydrates based on your upcoming training session. After a workout, aim to replenish your glycogen stores as quickly as possible.

After prolonged exercise, consume at least 1.2 grams of carbs per kg of body weight and 0.38 grams of protein per kg.

For peri- and post-menopausal women, consume this within 30 to 40 minutes to take advantage of non-insulin-dependent glycogen synthesis.

2. Eat Balanced Meals with Protein and Carbs:
At each meal, aim to include around 25% of your daily carbohydrate needs along with 35-40 grams of protein. For athletes with double training sessions, make sure to have a carbohydrate-rich snack (~30g) before the second session.

3. Maintain a Balanced Nutrition Strategy:
From breakfast to dinner, ensure you’re fueling your body with a mix of carbs and protein to promote recovery and health. Stop eating about two hours before bed to support optimal digestion and recovery.

By fueling appropriately throughout the day and tailoring carbohydrate intake to your activity level, you can avoid both LEA and LCA, and achieve better performance, adaptations, and overall health.

https://www.drstacysims.com/blog/restricting-carbs-hurts-performance-and-health

Then we have this article to review…

Fasting, Keto, Low Carb, All Zone 2 All the Time… Those Rules Are Not for Us

It’s hard to believe, but just a few years ago, menopause wasn’t part of the mainstream conversation. Since my book Next Level came out two years ago, the topic has exploded. Celebrities like Oprah and businesses realized the power of the menopausal demographic, and now, menopause information is everywhere.

Unfortunately, so is misinformation—especially for active women. Many of the mainstream guidelines target women who aren’t physically active, and they don’t apply to those of us regularly working out. This has led many midlife women to low energy availability because they’ve been told to cut carbs and fast during menopause. Let’s clear up a few myths that do not apply to active women, and really, they don’t apply to most women at all.

Myth #1: You Need to Fast

Fasting is often sold to menopausal women as the Golden Ticket for health and wellness (which, in many cases, is code for “weight loss”). Intermittent fasting—eating within a small daily window or cutting calories drastically a few times a week—gets pushed as a cure-all.

But here’s the truth: Intermittent fasting can be helpful for the general population struggling with metabolic diseases, but active women do not get extra benefits by layering fasting on top of exercise. In fact, it often backfires.

Women are more sensitive to energy restriction than men due to a neuropeptide called kisspeptin, which regulates sex hormones, glucose levels, appetite, and body composition. Fasting disrupts kisspeptin, leading to hormone imbalances, appetite dysregulation, and even changes in circadian rhythms.

When you add exercise to the mix, the problem gets worse. Energy restriction plus exercise raises cortisol levels, suppresses thyroid activity, and increases belly fat storage—all of which exacerbate menopausal symptoms. Contrary to what you might have heard, fasting does not boost estrogen levels, and studies done on young rats (not human women) have been misinterpreted to claim otherwise.

In short, fasting may work for certain health issues, but it’s not a magic solution for active menopausal women.

Myth #2: You Should Stay in Zone 2

Zone 2 training, or low-intensity aerobic exercise, is hugely popular right now, with many women being told to avoid high-intensity training to keep cortisol levels in check. While Zone 2 has its place—great for active recovery and endurance base building—it’s not the end-all, be-all for women.

Women’s mitochondria (the powerhouses of our cells) function better than men’s. We already have better mitochondrial density and respiration, so endless hours of Zone 2 training aren’t necessary for us. What’s more effective? Adding high-intensity intervals to improve both mitochondrial and anaerobic capacity.

Short, high-intensity sprints (under 30 seconds) are particularly beneficial for menopausal women. These types of workouts improve lactate clearance, fast-twitch muscle fiber strength, and overall body composition. Incorporating these into your routine helps mimic the hormonal boost we got naturally in our premenopausal years.

Myth #3: Carbohydrates Are Bad for Menopausal Women

Keto and low-carb diets are often marketed as solutions for menopausal weight gain, but for active women, cutting carbs can lead to low energy availability (LEA). This can decrease thyroid function, lower bone density, and exacerbate menopausal symptoms.

In fact, around 55% of people who train daily end up in a state of low energy availability, and women are especially at risk. Eating enough carbs is vital to avoid LEA. Endurance athletes need 4.5 to 7 grams of carbs per kilogram of body weight daily, while women doing moderate or intense training (like CrossFit) should aim for 3.5 to 5 grams per kilogram.

Menopausal women already face anabolic resistance, making it harder to build and maintain muscle. Keto doesn’t help here—in fact, low-carb diets increase BCAA oxidation, preventing the adaptations we need to maintain strength. Eating enough carbs also supports immune function, stress response, and recovery—all critical during menopause.

Myth #4: Supplements Are a Scam

While some influencers dismiss everything but hormone therapy, not all supplements are useless. Many have well-researched benefits, especially for women in menopause.

Adaptogens, for instance, help women manage stress by targeting the hypothalamic-pituitary-adrenal (HPA) axis, which controls the body’s response to stress. Menopausal women also benefit from creatine, which can improve strength, brain health, and even mood. It’s one of the most researched supplements and is especially useful for women dealing with brain fog and fatigue during menopause.

Myth #5: Every Woman Needs to Replace Her Hormones

I’m not anti-hormone therapy at all—it’s a valuable tool for treating menopausal symptoms, particularly hot flashes, night sweats, and osteoporosis risk. It can also help women struggling with the menopause transition.

What I am against is the idea that hormone therapy “replaces” your natural hormones and keeps you in a premenopausal state. That simply isn’t true. Hormone therapy provides low levels of estrogen and progesterone, but it doesn’t reverse the clock. Instead, it helps you manage the transition and reduce disruptive symptoms.

The Takeaway

Active women need advice tailored to their needs, not one-size-fits-all fasting or low-carb diets. Prioritize fueling your workouts with enough carbohydrates, mix up your training with high-intensity intervals, and be mindful of how fasting or restrictive diets may negatively impact your energy levels and hormones during menopause.

Summary of https://www.drstacysims.com/blog/mainstream-menopause-advice-is-misleading-active-women