Impact of iron deficient anemia

So I’ve been struggling for some time with feeling weak in general and on the bike. 2 years ago my ftp was ~120, now its 90 and that’s an improvement from 3 months ago. I’m a triathlete and I not only struggle on the bike, I struggle on the run and I really struggle to breath in the water. And to boot my legs burn or feel weak almost all the time.

This results in a whopping <1w per KG of power to weight. My ego has taken a beating but more importantly I’ve just been trying to figure out what is wrong. I originally thought I had some sort of lung deficiency (exercise induced asthma), then I thought maybe my aerobic engine was just really bad (seems odd given my history, but the last few years I’ve been in the slumps so maybe). Fast forward to now, I went to a new primary care doc…just to get a referall for a specialist (dermatology). They ran tests and low and behold I’m serverly anemic, specifically iron deficient anemia.

So, my questions are as follows.

  1. Could this be a major contributing factor in why I have no power?
  2. Is it helping or hindering to continue to train while my iron is low (I’m thinking if I do z2 type training, I can make the cells I have more efficient at transporting oxygen , so then once my iron raises I’d be even stronger aerobically).
  3. Has anyone suffered from this and fully recovered (most that I find online , people are still struggling after a year in). I also haven’t been able to find a lot of first hand information from athletes (vs general population)
  4. Could anemia play a role in having a reduced metabolism?

I did get a script for iron, I really wanted to get an infusion, but the doc won’t give me a referral and the center won’t do the injections without a script (not sure why, i’m willing to pay out of pocket)
I also am bumping up the red meat in my diet and taking liver/spleen pills.

I’m supposed to do my first half ironman in October but now i’m questioning if that is realistic. :cry:

If interested
Female, 41
My TIBC is high (500)
Iron is low (23)
Ferritin is low (8)


Yes, anemia is probably a major factor in why your power is lower than you’d like. I can’t really speak to questions 2 or 4, but I can hopefully offer some advice on how to get your iron and hemoglobin back to normal levels. All of our docs (I work at a hematology/oncology infusion center) will prescribe oral iron first and then move to IV infusions if oral is not tolerated. And, at least in the US, we would still need orders from a MD to actually do the iron infusion, regardless of how you pay for it.

With that said, try taking your oral iron along with vitamin C every other day (or even Monday/Wednesday/Friday if that’s easier to remember). Taking it every other day and with vitamin C maximizes absorption compared to every day dosing, and hopefully will cause less stomach upset. Keep drinking plenty of water and eating fiber as well, since iron can cause constipation.

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Thank you!! I have seen information regarding the alt day dosing. I’ll get some Vit C as well.

I was listening to a doc on a podcast (not sure where he was located) and he is a proponent of going right to injections but it sounds like i’ll just need to follow the process, and be patient.

Ok, so I completely understand what you’re going through because I’m going through it too. Hopefully I can offer some help.

Quick background: I’m a triathlete as well. All last year I struggled with severe insomnia. I figured that the constant fatigue I was feeling was primarily due to the sleep issues. I finally lost my patience with my doctor and got blood work in November - I’m anemic (hemoglobin at 116, ferritin at 11). I also have some other issues but your question is about anemia, so I’ll stick to that.

I’ll answer your questions first, then give more details on my ongoing experience.

  1. Could this be a major contributing factor in why I have no power?

In my experience, yes. Among others, anemia causes fatigue, dizziness, shortness of breath, insomnia, difficulty concentrating. Not only will these impact you on FTP test day, they also have a massive impact on your day-to-day training and have a big impact on your overall mental/emotional health which will impact your training and performance.

  1. Is it helping or hindering to continue to train while my iron is low (I’m thinking if I do z2 type training, I can make the cells I have more efficient at transporting oxygen , so then once my iron raises I’d be even stronger aerobically).

I trained through it. It was really hard, I often failed and felt pretty bad about myself and my recovery time was longer than I was used to. So training while you don’t feel great may have a detrimental effect on your motivation.

Running and swimming are low impact and I haven’t found any research to indicate that these cause or make you more susceptible to anemia. Running, however, does. Running is high impact and you damage red blood cells as the blood circulates through your feet - endurance runners are often at a higher risk for anemia.

You could dial back the running a bit or make sure to run on softer surfaces like trails or a track or a treadmill.

  1. Has anyone suffered from this and fully recovered (most that I find online , people are still struggling after a year in). I also haven’t been able to find a lot of first hand information from athletes (vs general population)

From what I’ve read, you can see improvement in three months through taking iron supplements. This doesn’t mean that you’ve “cured” your anemia, but that you’ve seen improvement in your blood work.

However, I couldn’t find any real defined benchmarks for ferritin levels in endurance athletes, male or female. My doctor was massively unhelpful here as well. Like you’ve found online, for some people it takes years and is an ongoing consideration.

  1. Could anemia play a role in having a reduced metabolism?

No idea. But if you’re tired and fatigued all the time you’re less likely to train and train well. And if you’re someone who eats when stressed, you’re going to gain weight.

I’m supposed to do my first half ironman in October but now i’m questioning if that is realistic

Everyone is different, but I think you would be fine. You have about 9-10 months to work on your iron levels and fitness. I would keep notes on how you feel and your nutrition alongside your training notes and have blood work done at 3 and 6 months to see how you’re trending.

I raced two 70.3s last year (June and end of July). June was tough but a 12 min PB, July was miserable (6 min slower than June) and recovery was brutal - I didn’t race again after July. It was really hard. I was going to race my first IM in the fall, thank god I pulled the plug on that.

My experience:

It had crossed my mind that I might be anemic in the spring, but I have a great diet and I eat meat. I even focused on increasing my dietary intake of iron throughout the summer and fall. In November, I got blood work done. Anemic (and also deficient in a few other things that cause fatigue, sleep disruption etc).

My doctor called and recommended that I eat more leafy greens and red meat. I called back and told her she could give me a reco for an iron supplement, or I could figure out which one to take on my own since my diet is already full of dark leafy greens and red meat.

I started taking: Fermax (2X150mg) and Vitamin D (2X1000iu). (I am also Vit D deficient). I also took a 10mg/day serving of Floradix for the first month.

I also did a lot of reading and changed how I timed my nutrition throughout the day. I realized that_how and when_ I was eating was likely contributing to my anemia. Here is what I learned:

  • Caffeine blocks iron absorption. Caffeine can have an effect as long as 1-2 hours after you have it, and can inhibit absorption even if you have your coffee/tea/etc an hour after your iron intake.

  • Calcium, Magnesium, zinc all inhibit absorption. So foods that are fortified with calcium (like cereal, dairy, etc) are going to block absorption of iron. So you want to keep an eye on nutrition labels.

  • Heme vs. non-heme iron - Heme iron is the type of iron found in meat, non-heme is the iron found in veggies. Non-heme is not easily bio-available, so you want to pair non-heme iron with a food that makes iron highly bio-avail:

  • Vitamin C/ascorbic acid - makes iron highly bio-available. If you’re eating a bunch of beans/veggies high in iron, pair it with a food that is high in vit. C.

  • Phytates - these are found in oats, whole wheats, beans, nuts, etc. These block/slow iron absorption. Vitamin C will help. Some veggies need to be cooked to release (not sure if that’s the right word) Vitamin C or breakdown phytates. or make iron more available. Spinach would be an example of this for iron.

  • Iron is more easily absorbed on an empty stomach, so take your supplements 1-2 hours before and/or after a meal. I take mine in the evening with either a piece of fruit for the vit. C or with half a Vitamin C supplement. This also means that I’m taking it as far away from my caffeine intake as possible. A lot of people seem to have stomach issues with iron supplements, I have a rock solid gut and have not have had any issues.

  • Vitamin B12 helps your body create new red blood cells. A B12 deficiency will contribute to iron-deficient anemias. If you didn’t have this tested, it might be worth considering this as a supplement and definitely having it tested next time.

  • Nutrition labels - Canadian guidelines say men should have a daily intake 8mg, women 18mg. However, nutrition labels in Canada are based off of a % DV of 14mg. So if you’re a woman basing your iron intake off of the % on the nutrition label, you’re in a deficit. Fun, eh?

How am I feeling now? (2 months of supplements and “reorganized” nutrition/diet timing)
Effing great. It is like I didn’t realize that my brain was on a massive dimmer switch and someone just flicked the lights back on.

Disclaimer - I was also having sleep issues and so a huge part of feeling better is that I went from sleeping an avg. of 3.5-3.5 hrs/night to 6 hours within the first week to now almost consistently 7!

  • I have increased my FTP by about 16% (I’m finishing up Triathlon Full Dist Base next week).

  • In my masters swim club lane, I went from even/slower than my 2 regular lane mates to smoking them on mid- to long-distances. I noticed this at about the 3-4 week mark, and I’m only getting faster.

  • Completely subjective, but the difference I’ve felt in my cognitive function is almost unbelievable. My memory has improved. My attention and focus has improved. My creative thinking and problem solving has improved. It’s like the neurons in my brain were trying and failing to fire through jello before, but I had no idea because I had just gotten used to feeling that way.

Once I get my blood work in Feb, I’ll be sitting down and sketching out my races and goals for the season. I decided I wanted to wait to see how my blood work looks and how I’m feeling before I could evaluate where I am with fitness and where I want to aim for.

Final Thoughts
You totally got this and I’m sure that you can still train for and crush your 70.3 in October. You know where you’re at and are taking steps to improve. That’s waaaay ahead of where I was a year ago!!

I know that everyone is different and that my experience is n=1. But I think the best way to look at this is to outline the steps you’re taking to correct the issue, making sure you execute your plan, pay attention to how you’re feeling and then have your repeat blood work done in 3 months.

Ps. Unless you live on the equator there’s a good chance you’re also Vit D deficient. Vit. D deficiency can cause/contribute to fatigue, depression, sleep disruption, and other really fun stuff. Vit D is soluble so take this one with a food that has fat in it.


Thank you so much!! I’m at work but I want to come back and re-read all the guidance you’ve listed here. I’m all in my feelings at the moment and emotional (not sure why), but its a relief to know someone understands and also i’m not crazy. I also have sleep (and depression) issues, which is why I was praying it wasnt in my head. I questioned if I had fibromyalgia or chronic fatigue syndrome…just looking for SOMETHING to explain why I feel this way. Part of my sleep issues are because I have periodic limb movement disorder, which also makes it difficult to recover or feel rested b/c you don’t get the rem sleep you need.

Its been super SUPER frustrating for sure, but I suppose its made my resolve stronger, I like to think that training healthy will seem like a cake walk in comparison but we shall see.

I do have floradix so I’ll keep that in the mix.

Puts a whole new spin on the term “Ironman” lol.

I recently switched to cooking exclusively with cast iron pots, pans, and baking sheets. One of the benefits of this (besides not getting cancer from the toxic non-stick I was using before) is an uptick in iron absorption from the foods I cook using the cast iron. You can read more here if you would like.

Best wishes to you as you overcome.

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Thank you! Will look in to that!!

No worries! I completely understand where you’re coming from. I was half-convinced I had cancer or something. It was when the doc tried to put me on anti-anxiety meds to help the insomnia that I snapped and really pushed for blood work.

When I got my blood work results and spent the day Googling every value that was too low, too high, or borderline it was like a lightbulb went off. I was too low or borderline for almost everything that has a symptom of fatigue, sleep disruption, insomnia. Seeing the results and realizing there was a physical cause behind how I was feeling was an emotional moment for me, so I understand you having all the feels :slight_smile:

I’m so glad that I could offer some information and help (just know that I’m not a doctor or in any kind of related field, so grain of salt). I also did chat with my buddy who is a med student while I was figuring this out.

My sleep started to improve the night that I started taking supplements. This is completely placebo effect since there is no way you would feel the effects of Vit D and iron that quickly, but simply having a plan that I was actioning helped me with the anxiety that I developed around not sleeping, which immediately started to help my sleep.

I found my (former-as-soon-as-I-find-a-new-doctor) doctor completely unhelpful and she gave me no information or advice other than greens and red meat. I wrote out a bit of a rant, but I’m just going say it was infuriating.

@GravelNut’s suggestion is great as well, can’t believe I forgot to include it! I’ve used a cast iron skillet to cook most of my meals for about 2 years. You could also try Lucky Iron Fish (they have research linked at the bottom of that page). It’s an iron fish that you chuck in soups/water while you’re cooking. It supposedly adds 4-7mg of iron (as claimed on their site).

Floradix - I’m kinda on the fence about this to be honest. It really only gave me 10mg elemental iron per serving vs. the 300mg I am getting from 2 supplements. I’m sure it’s helpful to help maintain levels once you get to a solid place, but I’m thinking it’s a drop in the bucket if you’re severely deficient.

Haha, you are going to love training once you start to get things under control :slight_smile:

Also, check out this video of Matthew Walker doing a Talks at Google. He’s a neuroscientist and studies sleep. His talk (and book - which I haven’t gotten my hands on yet) are about why sleep is so critical.


Hi, I never comment in blogs or anything:

But if you follow my guidelines!! in march you will be super super Strong!! (based in experience).

I HAVE felt YOUR PROBLEM !!! it is a horrible that feeling!! And if not well treated and diagnosed,you can be like me years having anemia (it took me 3 anemias during 1 year and a half)….

message me through fB if you want more info!!! …

Been checked by emathologist, ginecologist, endocronologist… and now i know the cause, if i had know the first time… i would have been cured since begining!!!

so My recoomendations to be fully recovered fast are:

  1. find THE WHY you are anemic (root of the cause). My cause was my periods + excersise that deepleted even more the iron levels.
    Until you find it, you can take all iron you can, but later you will be again anemic…
    If you dont have heavy periods, tell your doctors to do blood exams, to find out if there are hormones, or heart deficiencies….(some times heavy periods can be just more than 4 days of light period,or 2-3 days of heavy….

  2. Take iron in red meat, liver pills, , but also take real iron pills (which are much more stronger than taking just natural things).

  3. take at the same time you take your pills: blood builder (check it in amazon). it contains beet root, which is a booster of oxigen in the blood…and helps absorbe much more the iron you are taking (a doctor explained me, that from the iron you eat or take in pills, you only absorb 20%…so with this blood builder,it increases dramatically…and you recover faster.

  4. expect starting to feel after month 1…but perfectly until month 3…

  5. the brand of iron that you purchase: make sure they have iron+ folic acid+ vitamine B12 and C. (this are more expensive,but they dont make you sick after taking them, and they boost iron absortion). (when i was in my lowest levels and feeling crap…my doctor told me to take 3 pills a day)…

  6. when you viist yoru doctor, exagerate the information…so they really pay attention to you (my doctors did not pay attention to me, until it was a bigger problem)

  7. while you have anemia: you can keep training but try to be in zones 1 and 2 (pettit, carlson, and all those easy rides in trainerroad)… , 2-3 times a week as maximum (so you can recover faster, and dont loose much of your already existing ftp)…

So answering your question_

  1. Could this be a major contributing factor in why I have no power? TOTALLY, this is the reason!

  2. Is it helping or hindering to continue to train while my iron is low (I’m thinking if I do z2 type training, I can make the cells I have more efficient at transporting oxygen , so then once my iron raises I’d be even stronger aerobically).: YES YOU ARE RIGT: it would help you recover faster… zoones 3,4,5 consume lots of iron…

  3. Has anyone suffered from this and fully recovered (most that I find online , people are still struggling after a year in). I also haven’t been able to find a lot of first hand information from athletes (vs general population)- I am fine, but only after spotting the root cause.

  4. Could anemia play a role in having a reduced metabolism? - i dont know exactly, but you will feel tired, sleepy, irritable, sometimes high hr, you can feel tired even climbing stairs……

hope i helped,

contact me if you


@Nikki300 @camiech. Thank you for sharing your exxperience. It makes me feel that I am not going crazy. I am at Hb - 8 and low supply of blood as my doc calls it. Past few months, I have been doing more exercise and trying to control diet but I gained 8 lb around my waist and hips. It was so heartbreaking . I also have heavy periods but last couple months, I did not get my periods. My doc did blood work and found that all my CBCs for red blood cells are low. He says that I dont have blood supply to loose so no period. Any ways, I started taking iron pills and got my periods back . However, I have question that should I be walking every day till I recover from anemia ? How long will it take to start loosing weight ? I am bloated and dont feel as good with so much of extra weight. I would love to get inspired by people who has already gone thru this.

Thank you so much for your support.