ATC 330: Sports Drink Rundown, Training Considerations For A Woman’s Cycle, Going 80/20 with MAF, and More

July 30, 2021


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On this episode of Ask the Coaches with Lucho and Tawnee:

Joel asks:

Down on CarboPRO?

Hi guys. Been listening to the podcast for years so thanks for continuing to produce it!

I got the impression from the discussion during ATC 328 that you are down on Carbopro. I have no affiliation with the brand but do use it.  Is there something I should be concerned about? I don’t like Stevia products or sugary drinks. Carbopro has worked for me but I’m just curious if there is a reason not to use it.

What the coaches say:

Important points on sports drinks:

  • Blood flow diverted away from gut during exercise, making digestion more difficult.
  • This is why it’s so important to train your gut to tolerate fluids and calories, and find a good hydration/nutrition match not just wing it.
  • Most sports drinks are designed to make you want to drink more, even if you don’t need or shouldn’t be.
  • All the sports drink science matters but what also matters is YOUR UNIQUE NEEDS & N=1 trial and error!
  • If a product has worked for you, truly, then carry on. But if not or if you’re at all questioning your approach to hydration in training and racing then go deep to find your right mix…
  • Also, many sports drinks use a combo of different kinds of sugars to help optimize absorption. Check ingredient labels (more below).

Carb solution of common drinks/osmolality:

  • Gatorade 6% (this means 6 grams CHO per 100ml or 60g per 1L) (360mosm/L)
  • First Endurance EFS 8%
  • Cytomax 6-7%
  • Perpetuum 6-8%
  • Accelerade 7-8%
  • Skratch 4% (160mosm/L)
  • Osmo 3.2% (260mosm/L)


  • Osmolality is how many particles are in a solution. If your sports drink has too high an osmolality, especially from sugar(s), your body will likely dehydrate to some degree because these particles need to be transported by water- body draws from its other sources to pull more water into the gut to digest your drink, not a good thing. 
  • Depending on one’s hydration state, blood osmolality can range anywhere from 275 to 295 milliosmols (mOsmol) per kg of water.
  • Too high osmolality in your drink can cause bloating, sloshing, gut rot and an inability to rehydrate properly. (Typical sports drink is 300-360 milliosmoles, including Gatorade; Powerade is 350-390!)
  • Keeping the drink concentration lower than the osmolality of the blood helps better get fluids to blood and the muscles (this is known as optimize intestinal fluid exchange).
  • Fluid absorption largely in the small intestine (95%). Gels, highly concentrated sports drinks, etc, will sit in SI = increase pressure = body responds by pulling more water into gut. Many people who have GI issues may feel extra worse especially in those with very common GI dysbiosis conditions like SIBO.

Breakdown of common sports drinks:


  • 1 serving/scoop = 100 calories with 25g CHO.
  • Ingredients: “glucose polymer extracted from identity preserved GMO free corn.”
  • According to their website: “You need at least 200 calories (50g) per hour = 2 scoops mixed in 12 to 16 oz of water… It is low in osmolality even up to 15% to 20% solution in water (200 to 220) lower than body fluid osmolality (280 to 300). For example, the osmolality of sugar at 15% to 20% solution in water is approximately 800. Therefore, sugar at this concentration is too hard on the stomach. Relative to sugars, CARBO-PRO provides higher caloric density without exceeding osmotic balance.”


  • 1 serving: 90cal, 23 CHO (12g added sugar).
  • According to their website: “Mix 1 scoop into 8-12 fl oz water” (236ml-354ml) or mix 2 scoops into 16-24 fl oz water (473ml-709ml).”
  • Ingredients in orange flavor: Maltodextrin, Crystalline Fructose, Dextrose, Alpha-L-Polylactate Blend (L-Arginine, Glycine, Lactic Acid, Magnesium Oxide, Calcium Phosphate), Citric Acid, Sodium Citrate, Natural Flavors, Turmeric Powder (added for color), Less Than 1% of: Malic Acid, Potassium Citrate, Silicon Dioxide (Anti-Caking Agent), Ascorbic Acid, Xanthan Gum, Caffeine Anhydrous, Dimethylpolysiloxane (Prevents Foaming), Magnesium Oxide, Calcium Phosphate, Stevia Extract, Monopotassium Phosphate, Carmine (added for color).


  • 1 serving: 80 calories with 21g CHO (19g sugar) and 400mg of sodium per 500mL (16.9oz).
  • According to their website: “Our Sport Hydration Drink Mix has an osmolality of 160 mOsmol per kg of water, primarily because of the lower concentration of carbohydrate that we use and the absence of excess ingredients like coloring agents, flavoring agents, preservatives, and emulsifiers….Our experience that a 4% carbohydrate solution (4 grams of carbohydrate per 100 ml or 20 grams per 500 ml at 4 calories per gram) is the highest concentration of carbohydrate that we can have in our drink while still optimizing water or fluid transport across the small intestine.”
  • Ingredients in Lemon & Lime flavor: Cane Sugar, Dextrose, Sodium Citrate, Citric Acid, Magnesium Lactate, Calcium Citrate, Potassium Citrate, Lemon Oil, Lime Oil, Lemon Juice, Lime Juice, Ascorbic Acid (Vitamin C).
    (Verified Non-GMO, Gluten Free, Dairy Free, Vegan and Kosher).
  • Take a deep dive on the science of sports drinks and hydration by the Skratch folks here


  • 1 serving: 70 cal, 18CHO (16 sugar); Osmolality 260.
  • Ingredients: Cane Sugar, Dextrose, Trisodium Citrate, Calcium Citrate, Organic Orange Powder, Citric Acid, Potassium Citrate, Magnesium Citrate, Ascorbic Acid, Inositol Hexanicotinate (Vitamin B3), Pyridoxine Hydrochloride (Vitamin B6), D-Calcium Pantothenate (Pantothenic Acid), Riboflavin (Vitamin B2), Thiamine Hydrochloride (Vitamin B1), Cyanocobalamin (Vitamin B12), Folic Acid (Folate).
  • Stacy sims (founder) says: “From a science standpoint, the optimal pressure in there comes from a solution that’s 200 to 250 milliosmoles.” Too high is bad, but too low can cause dysfunction too she says.


  • 1 serving/scoop = 100 calories, 25 CHO (25g sugar).
  • Ingredients: Non-GMO Dextrose (Glucose), Non-GMO Sucrose, Citric Acid, Sodium Citrate, Sea Salt, Organic Flavor, Potassium Chloride, Magnesium Oxide, Calcium Carbonate.
  • According to their website: Mix 2-3 scoops with 24 ounces of water (this = 200-300 calories or 50-75 grams sugar per 24 oz/709ml).

UCAN (plain)

  • 1 serving/scoop = 90 cal, 22 CHO (0g sugar).
  • Ingredients in Plain: SuperStarch, complex carbohydrate of non-GMO corn.
  • Also very low osmolality.
  • An added bonus of sparing glycogen for fat oxidation; helping metabolic flexibility.

Meredith asks:

Bike training—80/20 with a MAF focus?

Hello!  I started MAF training a few months ago and that is when I stumbled across your podcast.  I’ve been listening to a wide variety of new ones and also doing the deep dive to some of your older ones.  I love the information you share!  I’m sure you have addressed this question plenty of times, so if you want to shoot me some episode numbers, I will start there.

My aerobic base has gone up considerably for running.  I started MAF with a 17 minute mile.  Yup.  THAT slow.  I’m now at about 11:30, so still a lot of room for improvement, but that is an insane amount of change in a few months.  My main sport is cycling though.  I really haven’t seen the improvement there.  I’m still puttering away and I’m fine with establishing more of a base, but I have a 109 mile trail ride coming up in September.  I did it last year and it was fine, but I want to go a little faster and also want to feel a little less wrecked afterwards.  I do most of my training indoors on a Peloton (4 young kids, more than 40 hour a week job, and living in the country makes it the best choice).  I recently started doing a Power Zone training plan to try to become a better cyclist. My heart rate is crazy high when I do most of the rides, but I’m starting to see myself improve finally.  Do I switch to more of an 80/20 type training now and keep my runs super light and just move the pedals on off days, or do I stop this hard cycling for 45-60 minutes and work more on a better base by keeping MAF and just doing a lot longer sessions?

For the first time ever, I’m excited for winter to really work on getting my mile time faster while running and getting more miles in on the bike, but whatever I can do to help me out in my ride 3 months from now is definitely the path I want to go at this moment.  Thanks so much!  ~Meredith from South Dakota

What the coaches say:

  • Based on run data, this athlete seems like a good MAF responder; don’t abandon this training method fully!
  • May need to cut back on running while building bike fitness.
  • Be cautious of too much intensity too often (eg on bike trainers with set workouts like Peleton or Zwift, this is more likely for some).
  • 80/20 incorporating MAF as part of the “80%”—you usually can’t go wrong and should get the results you desire with time, but training VOLUME matters. MAF requires enough volume to stimulate fitness.
  • For some, training at MAF heart rate on the bike may feel hard and more like a tempo effort. Getting comfortable with MAF as an aerobic Z2ish effort is a great thing.
  • Long endurance events need that time in the saddle; most athletes can’t “hack” with HIIT and low volume.
  • Utilize not just Z2 but also Z3 for aerobic training.
  • A couple key quality intensity sessions a week will help a lot.
  • Sometimes individualizing a Jack Daniels program (even for the bike) works well, cutting out the more intense sessions as needed, but his easy and T pace zones can be good on the bike too!


Scott asks:

180 Formula and are there HR training differences for women?

(note- this guy seems a bit confused on MAF and 180-minus age–this question is written in a way that makes it out as if they are different–so we can clear that up.)

Hi guys, this might seem like a very simple question but I am a runner and running coach.  I have dabbled with MAF training but felt that it doesn’t necessarily work for me to train this way full time but I do prescribe to easy running being an important part of training, especially marathon training where I believe that easy running not only helps to build your aerobic engine but for runners like myself shortly approaching my 40’s, it is essentially for recovery so that I can perform in the big sessions.

I read somewhere that a good rule of thumb for easy runs was 180 less your age, + 5 for athletes with a good fitness level.  At 39 I used this guide for my recovery runs the day after my speed sessions and long runs to make sure that my HR did not exceed 144 (180-39+5= 1).  I also tend to stick to somewhere around this for any long run that does not contain marathon paced efforts too.  So much so that I don’t even check my HR any more because I know what this pace feels like to run.

I coach my athletes to also follow this rule if they have a HR monitor but to varying success as some seem to be able to maintain a quicker pace than others at the same HR when they are relatively similar in fitness and in speed.

My questions:

  1. Is this rule of thumb just that? Ie, to get a more accurate easy/recovery run pace, there is a more complicated formula utilizing max HR or some other data?
  2. How does the 180-age rule of thumb compare for women?  Ie should I be using a different number?  This question might be answered in the above if there is a better formula that I can provide to my coaches.

I don’t like being too rigid on recovery runs so I prefer not to prescribe paces or HR.  I just like to tell them to make it easy but some athletes are better than others at A) comprehending the difference between comfortable and easy and B) swallowing their pride and running at an easier pace than they would like to or are used to.

I hope this question makes sense and that you can help – it’s probably something you’ve covered at length before I’m sure!

Thanks for your help, Scott

What the coaches say:

Females and training through the menstrual cycle

Take home points:

  • Each woman varies: understand how the woman with whom you’re working is affected by her cycle at various points and how she recovers.
    • Sometimes optimal (usually during follicular)
    • Sometimes it’s like fighting an uphill battle (usually during luteal)
  • May not need rest week per se but just difference approach to training.
  • May need lower intensity during 1) ovulation and/or 2) up to a week before period starts.
  • Key workouts with intensity and/or fat adaption focus are best during:
    • sometime after the beginning of her actual period for some;
    • during the first two weeks, i.e. follicular phase pre ovulation;
    • or for some post ovulation is fine too i.e. 3rd week of cycle.
  • Usually the 4th week is a rougher week for most women.

Low hormone phase (follicular; days 1-14ish)

  • The first two weeks leading up to ovulation. 
  • Great at using carbohydrate.
  • Usually can hit best high intensity.
  • Core temperatures lower (measuring BBT helps).
  • For many women this is the best time to get in key quality training.
    • Ideal time to race, fitness test, shoot for PBs.

Ovulation (days 12ish-16ish)

  • Hormones surge, estrogen peaks.
  • In some, this may disrupt the feel good training vibes & results.
  • However, some women still feel amazing if not more amazing – discuss, test, see for each woman.

High hormone phase (luteal; days 14ish-28ish)

  • Burning more calories- so eat more!
  • Coordination can be off (Tawnee shares a personal story on this).
  • Recovery can take longer.
  • Estrogen inhibits carbohydrate utilization, but it does help with fat burning.
  • Higher intensity may feel worse and more difficult.
  • Core temp: Progesterone increases the core temperature; heat tolerance is less- keep measuring BBT in AM.
  • Especially 4-7 days before period this is when most women feel like junk.
  • But specific nutrition practices and recovery practices CAN help offset the junky feelings.
  • MORE MAF during this time usually is an effective approach though some women may still handle intensity ok = communicate and individualize.

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