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  1. #1
    eri
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    question about cause of heart rate rise at end of long z2/z3 workouts

    Hi Experts,

    Sorry this is long, didn't want to leave out anything that might be relevant.

    I have a question about what has been happening on my long Saturday trainer rides, and wondering what I might have done wrong.

    First, here is the latest workout:

    https://www.trainerroad.com/cycling/...97-martin-hill

    There is a trend where my heart rate pretty quickly goes up towards the end of long sessions. The same higher heart rate happened the previous saturday. In that case I thought it was because I had no fan, and kind of, sort of... ran out of water. I thought the heart rate rose due to overheating but I felt pretty good still. But in this most recent case I am outdoors in 50 degree weather with a fan blowing hard, I'm not hot. I have plenty of water and felt hydrated. I'd eaten 480 calories of energy bar during the first 2 hours of the ride. The wattage isn't that high yet my heart rate goes to 160 for the final segment (my max is 195-200). And my legs hurt and I was having to grunt through that last segment. Yeah, no pain no gain but I felt pretty tired and it was pretty painful.

    On sunday I quit the ride early because I found myself in the same situation but even earlier in what is supposed to be an easier workout. Legs felt like hamburger. So clearly I'm not recovering fast enough to do the rides.

    I'm wondering if someone can explain what might be happening in my body that causes the heart rate rise and increased perceived effort.

    There is some sort of threshold being reached.

    I've now significantly upped my protein to better match what is needed by the training (1.5g/kg/day) so hopefully that will help but I'm curious about the sort of adaptation I'm after and an explanation of the symptoms.

    Can you suggest some things I might do differently? Is this sort of pain is part of adaptation (the good stuff) or have I been building my CTL too quickly and not recovering?

    On my mtb rides last year I used to get all 'bonky' after 2.5-3 hours. A solution that worked really well was to eat 350-400 calories per hour. Once I started eating carbs during rides I went from feeling miserable and shaking and shivering in the car on the way home to feeling pretty fine and doing hill intervals at the end.

    I'm wondering if I should follow the same food discipline for these long z2/z3 rides, or if the carbs defeat the purpose of base building.

    In this case I don't feel like I'm out of carbs though, feels like my muscles are worn out. So I'm wondering what is actually (physiologically) going on inside me on these long rides. Is it 'slow twitch fibers exhausted, utilizing fast twitch?' Or is it normal for 'cardiac drift' to have a sudden onset like this.

    Thanks!
    Last edited by eri; 03-15-2017 at 06:14 AM. Reason: wrong word
    the truth is always a gift because it offers the recipient of that information the chance to change the outcome - Grace Choi

  2. #2
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    Why would carbs defeat the purpose of base building? Unless you are trying to lose weight (not the same thing as building base), there is no need to calorie limit yourself and you'd get more out of your workout if you took on enough calories. Are you sure you actually processed 480 calories? It's one thing for those calories to go in your mouth, a completely different thing for them to hit your bloodstream and get to your muscles.

    Specific to your heart rate question, you're only elevated a few beats above the previous segment average. Your cadence is also a bit higher for the same target power. You're probably spinning a slightly higher cadence due to your legs feeling hit and that higher cadence translates to higher heart rate. Other physiological things are going on too, such as slight dehydration making it harder for your body to keep your core temp down, reduced ability for your blood to carry oxygen, etc.

    I think you're running out of calories and I think the 480 calories you took in was not fully realized by your blood stream. E.g., a good portion of that energy bar was taking a nap in your stomach. For an effort this long I personally would be shooting for ~750-800 calories in (~275cal/hr). I find that my hydration needs are insane if I take in solid foods, so I prefer to drink my calories.

  3. #3
    eri
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    Thank you for the reality check. I've been finding more about cardiac drift since I posted, not many causes: glycogen depletion, dehydration, heat.

    The calories were a pair of paleo bars. They didn't seem to provide much boost when I ate them. The effort feels so low until it isn't.

    I believe my hydration was good but I was still puddling sweat, so maybe not as cool as I thought, and maybe dehydrated even though I took in over 2 liters of water.

    I think I need a bigger fan that better covers my head, and I'll break out the tailwind for carbs and see if it helps.

    Gotta be a simple mechanical explanation.

  4. #4
    Formerly of Kent
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    Sounds like blood plasma volume reduction and cardiac drift.



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  5. #5
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    Quote Originally Posted by Le Duke View Post
    cardiac drift
    +1 for cardiac drift. Heart rate is a reaction to effort, it would be normal after a long effort, even a low intensity one, for it to climb a little.

  6. #6
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    Quote Originally Posted by eri View Post
    Thank you for the reality check. I've been finding more about cardiac drift since I posted, not many causes: glycogen depletion, dehydration, heat.

    The calories were a pair of paleo bars. They didn't seem to provide much boost when I ate them. The effort feels so low until it isn't.
    Sounds like glycogen depletion to me, basic blood sugar crash. Getting the sweats, racing heart, wooden legs...

    Why are you fueling with solid food during a training effort like this? It takes your body energy to break down that food. And your gut particularly can fight with the protein.

    There's lots of controversy about whether your body gets any benefit from consuming protein during a strong effort. In my experience protein doesn't matter. Getting a steady source of easily digestible carbohydrate and the right minerals and electrolytes is what your body wants. I'm all about the protein for recovery, but when you are in an effort your muscle wants glycogen.

    I use Tailwind Nutrition. Disclaimer: I am a Tailwind Trailblazer, which is an unpaid ambassador role. I have used Tailwind exclusively for on-the-bike fuel since 2012. I did a full 24 solo on nothing but Tailwind, and also an ITT of the Vapor Trail 125 using Tailwind and purified creek water for the whole lap.

    Nothing works for everybody, and I'm not a genius or even a great rider. But I'd recommend that you try it. Go to the website and read the Why Tailwind section.
    Tom Purvis - Salida, CO - http://teamvelveeta.tom-purvis.com

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  7. #7
    eri
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    Quote Originally Posted by TomP View Post
    Sounds like glycogen depletion to me, basic blood sugar crash. Getting the sweats, racing heart, wooden legs...

    Why are you fueling with solid food during a training effort like this? It takes your body energy to break down that food. And your gut particularly can fight with the protein.

    There's lots of controversy about whether your body gets any benefit from consuming protein during a strong effort. In my experience protein doesn't matter. Getting a steady source of easily digestible carbohydrate and the right minerals and electrolytes is what your body wants. I'm all about the protein for recovery, but when you are in an effort your muscle wants glycogen.

    I use Tailwind Nutrition.
    Hi Tom!

    First: I'm already a Lil' Lebowski Tailwind Achiever. I use it for big rides for sure. I don't like the cost but it is amazing stuff. I have 2 full boxes of green tea edition primed and ready for this coming season. I just don't like the cost.

    Second: I wasn't careful and said "Paleo Bar" where the actual product is "Caveman Energy Bar - Inspired by Paleo Mumble Mumble". They go down pretty easily and are $0.38 for 100 calories. Here's the nutrition facts - yeah too much fat.

    question about cause of heart rate rise at end of long z2/z3 workouts-cavemanbar_nutrition.jpg

    They don't work nearly so well as tailwind but... cheaper?

    Thirds: Back to the root question, what is happening, why heart rate rising? I suspect like all other real issues there were a combination of factors:

    1) I misunderestimated the ride's power zone. The hard workout that did me in was solid tempo, not Z2. It was well above my aerobic threshold so of course I was using sugar. 1700 calories is a lot for me to ignore diet during the ride.

    I've been chilling out doing so much Z2, watching women's track racing, that I've gotten used to a low steady heart rate and no need for food during the rides. I didn't pay attention to what the increased intensity meant. On the Saturday workout I depleted glycogen and sent my body into a bad state, feeding on delicious broken-down muscle. It made for a difficult recovery and I wasn't ready for the next day when I fell apart again on what should have been an easy Z2 ride.

    2) Body temperature regulation:

    It was pouring rain both days, relative humidity 100%, temp was low 50s. I usually ride at night when it is in the 30s and 40s. It was much warmer and humidy meant that my cooling didn't work as well as I'm used to.

    I had the fan pointed across my legs and lower body so no cooling for my head. I didn't feel hot but suspect I was actually overheating. Might explain the puddle of sweat on the floor.

    3) Longer term diet. My diet didn't have much protein. Maybe 40-60 grams/day where at my weight (~80kg) I should be at 100-120g/day. I've significantly upped my protein intake through the day and hopefully it helps me recover better. Will take days and weeks to know for sure.

    Last night I did another 2.5 hour Z2 ride, 158 average watts. I pointed fan at my face/head and combined with the drier 40 degree air it really helped me to stay cooler. I drank too much water though, wanted to pee for the final 40 minutes. Heart rate averaged 127, max 142 during some high cadence and one leg sessions. Felt fine afterwards, and even more fine after a giant vege salad and 12oz of bison burger. Legs and body feel good today.

    Tonight is another longer tempo ride which is the real test. At least I'm going in knowing it is z3.

    Did bunch of browsing on cardiac drift. Seems root cause is 1) temperature regulation, 2) glycogen depletion and 3) dehydration.

    So now and especially as the weather warms I think I'm going to need a bigger... fan:

    question about cause of heart rate rise at end of long z2/z3 workouts-biggerboat.jpg
    the truth is always a gift because it offers the recipient of that information the chance to change the outcome - Grace Choi

  8. #8
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    #1. Get a big fan. Bigger than you think you need. Two of these work great: https://www.amazon.com/Lasko-2265QM-...ords=20+in+fan

    #2. Point the fans at your torso, not your head.

    #3. Cardiac drift is normal, don't fret about it too much provided you are using a power meter.

    #4. Nutrient timing is key for trainer rides that are longer or more intense. You want to get some carbs in your system about 90-120 minutes before you ride and depending on the effort, have some on hand.

    For example, if I am going to do a 3x15 sweetspot session @ 90% of FTP at 6pm, I'll get some pita chips and some fluids in around 4:30pm and keep a Honey Stinger waffle on hand that i'll eat during the first rest period, so its ready for the last interval.

    Because there is no coasting on the trainer, you are going to get somewhere between 30-50% more overall stress compared to an outside ride. i.e. a two hour ride on the trainer is like a 3 hour ride outside due to coasting and cooling.

    #5. Depending on the effort, you may want some type of recovery calories afterwards. My general rule is that if I am working on any type of high tempo, threshold, or V02 max work or I am putting out more than 1000kj during the ride, I'll eat a cliff protein bar after (which has about 20g protein and 30g carbs). It's not the ideal recovery snack but its easy and helps be recover and make sure there is enough protein available.

    This system has worked well for me for the past two years where I do the majority of my training on the trainer and I have lost over 40 lbs and gone from 250w FTP to 300w.

  9. #9
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    I also honestly can't advocate for you to use that type of macro mix for a bar on the bike. Your body has more than enough fat to fuel your rides while it has a limit on glycogen/carbs.

  10. #10
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    Quote Originally Posted by Udyr View Post
    I also honestly can't advocate for you to use that type of macro mix for a bar on the bike. Your body has more than enough fat to fuel your rides while it has a limit on glycogen/carbs.
    Agreed. You'd be better off eating twinkies.
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  11. #11
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    I am just through my first bag of Tailwind after hearing about it for a few years on some podcasts I listen to. I am glad I tried it, and only regret that I waited so long!

    I have experimented with either 2 or 3 scoops ( each scoop is 100 calories) and found a sweet spot with 2.5 scoops.

    I have done rides with just Tailwind and then experimented with Tailwind + a Clif Bar mixed in. Felt better without solid food, but need to test that a few more times to be sure.

    The taste is pretty light compared to some of the others (I've tried almost everything out there over the years). And, it is compelling to not need to consume anything but Tailwind.

    Finally, I am training for Leadville and as of today, plan on fueling the day on Tailwind. I will experiment with longer and longer rides and just Tailwind. So far, I have gone 4 hours and felt pretty good.

    Didn't mean to make this a Tailwind commercial, but think the OP could benefit from my experience.
    I was too drunk and too much in pain to ride. Good times. - TacoBeer

  12. #12
    eri
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    Quote Originally Posted by tjkm View Post
    Didn't mean to make this a Tailwind commercial, but think the OP could benefit from my experience.
    I am the OP and mentioned tailwind in my second post. Stuff is great, am a believer. Green Tea FTW. I used tailwind for a 9.5hr race (though I also supplemented with whatever else I grabbed from aid stations, especially clif smoothies.) I just don't like paying so much to feed for typical trainer workout. At home I should be able to find something cheaper that works as well.

    The weird thing about last Saturday's ride was that the heart rate went into the 160 for a relatively low effort, not simple steady cardiac drift, it was like I hit an effort wall. That is the thing I couldn't explain. Bonk?

    It has been a whole week of higher efforts. The whole week I was much more intentional about protein, ensured I got 120g/day. Eggs, bison, fish. Felt strong the whole week, never felt like my recovery wasn't keeping up (unlike the week before.)

    For saturday and sunday I cooked up a heap of baby potatoes, kept in a bowl next to me while on the trainer. Ate on demand. Carbs. Yum. Seemed to work ok, at least satisfy.

    I redirected the fan to my chin so it blasts my face and upper chest. I got out another fan and point it at low speed to my lower torso.

    Rain has stopped, humidity is way down, temperature down into the high 30s so cooling worked much better. No more puddle of sweat, just a few drops.

    The week went really well, heart rate stayed fully controlled.

    Saturday was mount bond, 3hrs at 70-80%. No heart rate spike at the end. Drank 3 bike bottles and a 4th full liter.

    https://www.trainerroad.com/cycling/...372-mount-bond

    Sunday was Lyell, 3.5hrs at 60-70%. Again 3 bike bottles and a half liter.

    https://www.trainerroad.com/cycling/rides/5549111-lyell

    Saturday went really well, no pain, no stress. The easy final 1.3hrs of sunday were painful. Heart rate was well controlled but legs were quite sore. Was so cool on sunday night that I left my coat on the whole time. As you can see, heart rate drifted up, but a slow drift no spike even though my legs were really hurting at the end.

    So...

    Not enough evidence to be sure if there was a single cause. Probably a combination. This week's improvement could have been the protein increase for improved recovery, could have been better/more carbs during ride, but I feel that the primary cause of the high heart rate was insufficient cooling.

    I love tailwind for long rides out in the world but it seems like overkill for a ride on my porch. Anyone want to share hot tips for home cooked food to eat while on the trainer?
    the truth is always a gift because it offers the recipient of that information the chance to change the outcome - Grace Choi

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