Hey Saturday family!
“I don’t know if you know this, but endurance sports suck,” Alex said today as he slumped on our RV couch, blood pressure cuff on his arm and sodium water slurry in his opposite hand trying to resist his paralyzing faintness. The hilly 2026 XTERRA Worlds run course at 7000ft was getting a moment of respect.
Alex, the formerly 240lb national team bobsledder who used to loathe any forward movement that did not involve either perfectly flat terrain or the thrill of a descent was getting fitter. “It’s still dropping,” he said, shaking his head with a slight smile before taking a few more big gulps of his salty water. I wasn’t sure if he was curiously analyzing the substantial effects of altitude training and the hydration requirements of training in it or just impressed with his improving cardiovascular fitness - or both. “I’m not going to let hypovolemic collapse set in.” He gestured to me as if to ask urgently for more of what he was drinking.
What was happening and why the blood pressure cuff? Why did his threshold workout while previewing the sprint course leave him feeling so overly faint and terrible and how does all of this apply to all of us who have not previously been 240lb bobsledders?
Reason 1: (no fuel or hydration) In my haste to get my run in before the approaching lightning storm was upon us, I forgot my running flasks so Alex generously (and perhaps imprudently) gave me his. Not only did he not have the fuel and hydration that he needed to accommodate his normally heavy sweat level, but the dehydration effects were acutely worsened with the altitude. Dehydration reduces blood volume meaning that there is less blood in the circulatory system - leading to decreased blood pressure (which causes faintness if extreme) with an elevated heart rate to boot. (Carbs also played a role here, but that will be a topic for another day).
Reason 2: (altitude’s compounding effects) Altitude, when not accustomed to it is sneaky and robs athletes of their precious blood volume often faster than they even realize it’s happening. Anyone who travels to train at altitude from sea level has felt like a fish out of water while gasping for air during a hard effort…(or maybe that’s just me)? All of that harder breathing at altitude results in more water being lost through the humidity of each breath for a given pace or power output. (I’d recommend scaling efforts at altitude but I’m sure you are all doing that already! ;)).
Drier air also makes sweating less noticeable. While resisting the urge to go down the mechanisms rabbit-hole, I’ll just say that several of the physiological changes that your body goes through while acclimatizing to altitude also increases urination and decreases thirst sensation - all of which contribute to worsened dehydration. (Blood plasma also drops, concentrating hemoglobin as a normal adaptation effect, meaning that there is less blood volume to spare).
Reason 3: (changes in fitness level) Under normal circumstances, Alex spends most of his waking hours coding the app in the RV garage, meaning that he only gets a few solid hours of training in per week. However his weekly exercise volume has been increasing since he decided to sign up for his first off-road triathlon next month. Now that his training load has been increasing over the past several weeks, cardiovascular fitness has been improving rapidly which has been contributing to a reduced resting blood pressure.
Reason 4: (resting BP, medication - ie the breaking point) Alex is genetically predisposed to having slightly higher than average blood pressure and therefore takes a low dose of lisinopril to manage it under normal circumstances. Some blood pressure medications (like lisinopril) work by inhibiting the production of a hormone that is responsible for blood vessel constriction, sodium and water retention, and thirst sensation upregulation when blood volume drops. On a normal day that’s exactly what is needed. On a hot, dry, high-altitude day with no fuel or hydration in sight his body was not able to do its job to prevent his blood pressure from falling too far which is why Alex ended up in a miserable state with the BP cuff, and the need for the sodium water slurry. On top of that blood pressure naturally drops temporarily post hard exercise session making matters worse.
As you might expect, people with naturally lower blood pressure also suffer at altitude if sodium and water intake is insufficient. For these people even a small amount of blood volume loss can leave a person feeling weak and lightheaded. Athletes in this category often need significantly more sodium than the average person.
All four of the factors above contributed to today’s fiasco and the good news is that all of these are pretty easy to fix. Most of you are probably more dialed in than we are especially on days like today. Even we don't always nail our fueling and hydration because life happens, and that's exactly why we've been working so hard to try to make this process simpler and easier for everyone (ourselves included).
There are many reasons that a person may feel faint or weak during training - not all hydration or blood pressure related and it is worth talking with your doctor about to rule out any potential serious issues. If you are taking blood pressure medication I also do not suggest stopping or decreasing your dosage without talking with your doctor first! However, please be sure to let your provider know if you are training more consistently or are training in hotter or higher conditions as these may change your medication requirements. If you are not on any meds, have normal blood pressure, and are feeling faint and weak during training, sodium and water inadequacy may be a contributor and need to be increased.
📝 Practical takeaways:
1. Altitude often requires more intentional hydration strategies:
Faster breathing, drier air, increased urination and suppressed thirst sensation all add up. Do not neglect your intra-workout fuel and hydration!
2. If you use Saturday:
If you're training or racing at altitude, bump your sweat level up a couple of clicks in the app settings. That should do the trick.
3. If you have high blood pressure, take BP meds, or start feeling faint during your training:
You may need more sodium and water during training than you think. As your fitness improves, you might even end up needing less medication, but please talk with your doctor first.
4. If you have low blood pressure:
You probably need more sodium. For more on this, check out our sodium video on YouTube.
💬 We want to hear from you!
The goal of Saturday is to take the guesswork out of trying to figure all of this out so you can just go out and do what you love to do without issues. If you have any questions about any of this feel free to reach out via email or you can also schedule a consult call with Alex too. I promise he’s more thoughtful about others’ performance and health than he is about his own. 😂
Are you looking for coaching or know someone who is? I’m opening up a few 1:1 spots. Check out my website here: michelleihowe.com
~Michelle
