Mini Pause #11: Speeding Up & Going Hard: Zone 6 Training Benefits

Note: In the Mini Pause #10 email, some new formatting got the best of us and a few essential links were missed. Here’s the polar heart rate monitor I mentioned. And all [*] reference links are now fully functional in the web edition.

Speed Up Your Cardio: Why Zone 6 Training (Yes, Sprinting!) is Essential to Your Fitness

TL,DR (too long, didn’t read)

In addition to working your base with Zone 2 training, you also want to be training your top end to preserve your power and speed. This type of training biases training of the type 2 fibers. There are three main ways you can train your fast twitch fibers: 1) speed training, 2) plyometrics, and 3) resistance training. We’ll explore each of these in the coming weeks. Today, we explore how to structure speed training into your current cardio regimen.


In Mini Pause #8, I discussed the importance of Zone 2 training for mitochondrial and cardiovascular health in menopause. We received hundreds (and hundreds!) of questions asking about where sprinting training comes in. So that’s the subject of today’s issue! Ya girl always has your back.

While Zone 2 training should make up the base of your cardiorespiratory work, it’s essential to train the top end of your cardio range, too.

As early as your mid-20s (I know…good grief!), you start to lose your fast twitch muscle fibers (aka the muscle fibers that contract quickly and primarily use glucose as their fuel source) at a rate of 1 percent per year.

As you move through perimenopause, the loss of estradiol contributes to a loss of muscle satellite cells [*]. Satellite cells are muscle stem cells that are responsible for muscle regeneration and adaptation. As you lose these cells, it becomes harder to grow and repair your muscles.

There are several ways to train type 2 fibers. Over the next couple of weeks, we’ll focus on two main ones: speed training and plyometrics.


Speed Training / Sprinting

Sprinting is one of my favorite ways to train up type 2 fibers. It’s available to everyone. All you need is a pair of trainers and a road.

True sprint is something you can do ALL OUT for 10 to 30 seconds. No more. There are a few reasons for this.

1: In order to sprint, there are several energy systems involved depending on the length of time you’re doing it. The longer you’re sprinting, you will, by necessity, be gearing down into slower energy production systems. Meaning – also by necessity – that your sprint will be getting slower.

The first 5 to 10 seconds of any sprint is going to be fueled by the phosphocreatine system [*][*].

At that 5-10 second mark, you peter out of this energy system. This is a short-lived system with the energy to power your muscles coming mainly from the stored energy within the muscle itself.

Think about the excitement of a 100-meter dash at the Olympics; they are only tapping into their phosphocreatine system!

After about 10 seconds, you move to an energy system called glycolysis. You’ll notice your sprint markedly slows at this junction point. Glycolysis, when you are still sprinting, peters out around a maximum of 20 seconds after that.

Think about the 200-meter dash at the Olympics; the first half of the sprint is the phosphocreatine system and the second half is glycolysis. When you’re watching the Olympics in Paris this year, you will no doubt be thinking about this little factoid.

2: The second reason for keeping an all-out sprint under 30 seconds is psychological. If you know you’re going to be sprinting for one minute or 45 seconds, you’re going to “manage” your energy output to last that long.

There are several major benefits of sprint training that as a perimenopausal or menopausal woman you do not want to gloss over. They are:

ANABOLIC: When you’re sprinting all-out max power, you’ll build muscle [*]. While steady-state cardio (including Zone 2) can be catabolic, this type of training signals the muscle to develop. This happens even in a fasted state or if you don’t eat for two hours after a grueling sprint. I’m not recommending you do either of these; sprint fasted or don’t eat afterward. You choose what’s right for you.

But let’s say you (or me on a recent Monday) wake up late, haul ass to the gym, and get your sprints in and then oops! You remember you have an important meeting in 30 minutes and don’t have time to eat a proper post-meal workout. Based on the results of this study [*], that doesn’t seem to matter.The point? Sprinting is a strong anabolic (growth) signal to the muscles in the absence of food.

INCREASED TESTOSTERONE & GROWTH HORMONE: The other benefit of course is an improvement in hormonal composition, similar to what we see in resistance training. Post-sprinting, women have a greater rise in testosterone and growth hormone [*]. Both are important for lean muscle preservation, fat management, and mood. I know my Bettys want that trifecta!


Let’s keep this super simple and say your maximum sprint is going to be 10 to 30 seconds.

  • Recovery should be about the same length as the sprint, so somewhere between 10 to 30 seconds, and then repeat this anywhere from six to 12 times.
  • You can sprint on the road or on a piece of cardio equipment you like. I use my CAROL Bike and I love their “Fat Burn 30” workout. This Tabata-style cycle session features eight seconds on, 12 seconds off for recovery, repeated 30 times. I love this because it’s low impact, and I can track my progress in terms of power output over time.
    • (If you’re curious about this AI-powered bike, click the link provided and use code DRSTEPHANIE to save $100.)


Choose one day of the week and make it your sprint day. Time of day is irrelevant; just get it in when you can get it in!

  • Start with a 10-second, ALL-OUT sprint. Whatever that looks like for you. Recover for 30 seconds and repeat. Do this eight to 10 times.
  • Over the next several weeks, try to claw back your recovery so that you’re sprinting and recovering at a 1:1 ratio. Meaning, if you’re sprinting for 10 seconds, you’re resting for 10 seconds.
  • Over time, you can increase your sprint and recovery by a few seconds, but max out at 30 seconds on, 30 seconds off.

Question of the Week

Q: How to tell if I’m perimenopausal? I’m 41, had hot flashes for a week and my period came eight days early.

Welcome to perimenopause, friend.

Perimenopause starts for most of us in the mid- to late-30s with a progressive and steady drop in progesterone. We can become symptomatic in our 40s (as you have), with irregular periods, raging PMS, sleep disturbances, and the onset of hot flashes and night sweats.

Many women who’ve dialed in their nutrition, exercise, and stress management can reduce and alleviate many symptoms of perimenopause. You can also consider seeking out hormone replacement therapy options.

Other signs and symptoms of perimenopause may include:

  • Heart palpitations
  • Irritability & moodiness
  • Trouble staying asleep
  • Lower sex drive
  • Vaginal dryness / poor lubrication
  • Lack of focus & poor concentration
  • Short-term memory lapses
  • Itchy skin
  • Achiness through joints and tendons
  • Slower recovery from weight workouts
  • Hair loss and hair thinning
  • Fingernails becoming more brittle
  • Dry skin, dry mouth, dry eyes
  • Sensitive teeth
  • Restless legs
  • More facial hair

While this is not an exhaustive list, you can see perimenopause is an experience of the entire body and brain.

The whole point of this newsletter is to arm my Bettys with tools to better navigate perimenopause!


I’ll be answering your questions every week right here in the Mini Pause! Let me know what’s on your mind. I’ll be checking for both questions and feedback at


HEALTH TOOLKIT: I’ve compiled numerous resources for you on my brand new website. These resources are for my Bettys who are still cycling, experiencing symptoms of perimenopause, or going through the menopause transition. Some items are appropriate across each category, and some are specific for each one. Everything I recommend, I use myself. That’s my rule. I invite you to look around