Aerobic exercise, anaerobic exercise, and the relationship between the two.

This is a thing I've been wanting to circle back to for a bit, and I'm putting it in my blog despite the fact that it might be a short post, because I want to include references for future-me.

In general, what I'm trying to express here is the reason that I, personally, need to train cardio. This requires an overview of how aerobic and anaerobic exercise work, as well as a bit of a dive into the biochemistry of energy production.

The tl;dr of how I think about it is that anaerobic muscles create energy debt, while aerobic muscles pay it back. This one-sentence breakdown isn't the full story on the subject - it's not as though all muscles or exercise are completely one or the other. But it is a shorthand of the full version.

(As a note, I definitely can't figure out how superscript works in the new Blogger format, so I'm just going to bold-italicize references unless I decide to go back and fix them in the HTML view thinger.)

One last note before the body of the thing - I am no scientist, so it is likely that I got some parts of this wrong. Please, if you have the expertise to do so, let me know where I'm wrong. I want to gain knowledge, and being told where I'm wrong is a wonderful way to do it.

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The traditional wisdom around exercise is that we have two muscle types:

    short-twitch fibers, used anaerobically for quick and hard movements, creating energy by consuming lactic acid which is then processed into sugar by the liver.
    long-twitch fibers, used aerobically for slower movements, using oxygen to produce energy in a more efficient way using mitochondria to process sugar.

Sure, there is also the smooth muscle of the heart and organs, and the mixed types of muscle fibers. But in general, this is the way that things are outlined, and these muscle fiber types are talked about as though they are completely different systems. In reality, these muscle types operate together both in a physical power-generation level, and on a chemical energy-generation level. This is why for someone like me, for whom the limiting factor in running is not the strength of my legs, it is important to do aerobic exercise in order to increase both aerobic and anaerobic muscular capacity over time.

The energy currency of the body is ATP. This is what our organs, muscles, and brains use to do things. We can produce ATP through two ways - using oxygen or not using oxygen. Using oxygen, we net 38 molecules of ATP per glucose molecule. When not using oxygen, we only net 2 molecules of ATP per glucose. However, the latter reaction is 100x faster. (7) Looking at this in the inverse - this means that committing glucose to aerobic energy production will produce about 1/5 of the energy that would be created by that same glucose anaerobically, in a very short time-frame.

The aerobic method of energy production does produce some waste products, but overall it is very efficient and those waste products are removed from the body. The anaerobic method, however, produces lots of lactic acid, which can be disposed of in two ways.

The first, and most commonly-mentioned in textbooks, is that the liver processes lactic acid back into glucose, consuming ATP to do so. From there, the glucose can be used aerobically by the liver and other tissues of the body.

The second method is removal by other skeletal muscle. (1) Primarily-aerobic muscle is more likely to take in lactic acid from the bloodstream (4). From there, lactic acid forms lactate and is eventually oxidized into pyruvate, and can be taken directly into the early stages of the citric acid cycle, which is the aforementioned means of producing 38 ATP from one glucose - still producing most of the ATP that it would have otherwise produced.

This means that not only does one's ability to clear lactic acid improve as one gains more slow-twitch or aerobic musculature (5), that same lactic acid is used by that musculature to produce more energy.

(As an aside - apparently lactic acid is not actually the thing which causes muscles to burn. It's free hydrogen ions, produced as part of anaerobic effort, which get used to combine with lactic acid to form lactate.)

This is why aerobic exercise is important. Because the more aerobic musculature you have, the more energy-per-second you can produce. While anaerobic exercise improves on-demand power production, aerobic exercise is what increases one's ability to both produce power over a longer period of time, and to recover from the debts incurred to yourself by doing anaerobic effort.

(As another side note - your body is always doing anaerobic effort. The smooth muscle of your heart primarily gains energy anaerobically, which means there will always  be at least some small amount of lactic acid being produced. (6))

As an aside - the ability to process lactate is important to mental health too. In the brain, it behaves as a neurotransmitter. When infused into the bloodstream, it causes panic attacks. (8) Given that the blood-brain barrier allows lactate to pass easily (9), it would make sense that muscular capacity to oxidize lactate into pyruvate would be useful for reducing anxiety by reducing lactate build-up.

(Edit: Aww dang, I meant to mention that apparently the body chugs through lactate faster if you are doing some amount of exercise - for rowers, something like 40% speed was best for faster recovery, even better than full rest (3). So, ignoring that I have no idea how this interacts with heat sensitivity, you will recover faster if you walk around or something after you get done doing something super strenuous.)

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As a final side-note, doing the research for this post makes me wonder if there is a system in the brain parallel to fast-twitch and slow-twitch muscles. This would be anxiety-driven versus relaxation-driven thought and action.

As someone with ADHD, I often find myself completely unable to motivate myself to do anything without a deadline or some sort of anxiety looming over my head. Given that lactate, glucose, and pyruvate can all cross the blood-brain barrier to some degree, it would make sense that they could influence the type of thinking one does. They are also all able to be consumed as fuel by the brain.

It would make a kind of sense that the brain would get used to using and producing one type of fuel or another. I wonder if this would create metabolic changes in the brain in the same way that working aerobic or anaerobic musculature increases your capacity to do aerobic or anaerobic work.

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A BUNCH OF SOURCES:
(yes I realize I'm mixing citation types and no I will not fix it)

(1) Pagliassotti MJ, Donovan CM. Role of cell type in net lactate removal by skeletal muscle. Am J Physiol. 1990 Apr;258(4 Pt 1):E635-42. doi: 10.1152/ajpendo.1990.258.4.E635. PMID: 2110420.
https://pubmed.ncbi.nlm.nih.gov/2110420/ 

(2) Lactic acid recovery profiles following exhaustive arm exercise on a canoeing ergometer S.J. Baker PhD and N. King BSc
https://bjsm.bmj.com/content/bjsports/25/3/165.full.pdf 

(3) Koutedakis, Y, and N C Sharp. “Lactic acid removal and heart rate frequencies during recovery after strenuous rowing exercise.” British journal of sports medicine vol. 19,4 (1985): 199-202. doi:10.1136/bjsm.19.4.199
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1478395/ 

(4) Juel, C, and A P Halestrap. “Lactate transport in skeletal muscle - role and regulation of the monocarboxylate transporter.” The Journal of physiology vol. 517 ( Pt 3),Pt 3 (1999): 633-42. doi:10.1111/j.1469-7793.1999.0633s.x
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2269375/ 

(5) MacRae HH, Noakes TD, Dennis SC. Effects of endurance training on lactate removal by oxidation and gluconeogenesis during exercise. Pflugers Arch. 1995 Oct;430(6):964-70. doi: 10.1007/BF01837410. PMID: 8594549.
https://pubmed.ncbi.nlm.nih.gov/8594549/

(6) Barron JT, Parrillo JE. Production of lactic acid and energy metabolism in vascular smooth muscle: effect of dichloroacetate. Am J Physiol. 1995 Feb;268(2 Pt 2):H713-9. doi: 10.1152/ajpheart.1995.268.2.H713. PMID: 7864198.
https://pubmed.ncbi.nlm.nih.gov/7864198/

(7) (stolen reference from Wikipedia) Stojan, George; Christopher-Stine, Lisa (2015-01-01), Hochberg, Marc C.; Silman, Alan J.; Smolen, Josef S.; Weinblatt, Michael E. (eds.), "151 - Metabolic, drug-induced, and other noninflammatory myopathies", Rheumatology (Sixth Edition), Philadelphia: Content Repository Only!, pp. 1255–1263, ISBN 978-0-323-09138-1, retrieved 2020-11-02

(8) Riske, Laurel et al. “Lactate in the brain: an update on its relevance to brain energy, neurons, glia and panic disorder.” Therapeutic advances in psychopharmacology vol. 7,2 (2017): 85-89. doi:10.1177/2045125316675579
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5315230/

(9) Knudsen GM, Paulson OB, Hertz MM. Kinetic analysis of the human blood-brain barrier transport of lactate and its influence by hypercapnia. J Cereb Blood Flow Metab. 1991 Jul;11(4):581-6. doi: 10.1038/jcbfm.1991.107. PMID: 2050746.
https://pubmed.ncbi.nlm.nih.gov/2050746/

One Fact of Tall Versus Short

As a long-time tall fencer, tall-ologist and tall-ographer, I have opinions on the tall-versus-short fight. We recently, at my practice, ran an exercise to demonstrate the differences in mechanics between being tall and being short. This inspired me to write down some thoughts I have had for a while.

Behold this beautiful drawing I have made.

Here we have Doroga, with his arm in a sling, versus Remy, with abs and a swole arm.

I have drawn many lines on this drawing. The rough sketch is of two fencers, a tall fencer and a short fencer. The teal line connects their shoulders - it is the line around which all blade engagement is centered. We’ll get back to that line in a bit.

The pair of red lines are the lines on which Remy could attack at full extension and hit a vital area. Any farther outwards and he will not hit Doroga in a vital area.

The pair of orange lines are the same for Doroga.

The orange and red arcs between their respective lines are an arc showing the relative distance gained or lost by raising the blade from the shoulder, with arm and blade fully-extended. The arcs assume that Remy and Doroga have the same arm-plus-blade length, which will be important later.

The dark blue line is the shortest line for Doroga to hit Remy. Similarly, the light blue line is the shortest line for Remy to hit Doroga.

If one is approaching, it is important to cover those lines first, because those will be the lines that your opponent will plan to attack first from out of measure. Anything deeper requires more time, and thus will give you more time to plan a defense.

As such, it is important to cover those lines first. One way to do this is to attack through the line, in such a way that at the point of contact with your opponent’s body, your blade will still be crossing the line of shortest ingress.

The rest of this post assumes that you accept that the above is true. Or at least, true enough.

For Doroga, this means attacking at just about any target below the teal line. For Remy, this means attacking at just about any target above the teal line.

This presents several difficulties for Remy. Doroga has a lot less head than he has body. This is simple human anatomy - the area above the shoulder is smaller than the area below the shoulder.

Doroga is fortunately attacking Remy’s body. This means he has much more valid target area to hit than Remy does, both in terms of width and length. He can afford to be sloppier.

This partly explains a trend that I have seen. People who practice Destreza and other styles which involve standing straight are usually taller humans. Given that most “true” attacks in Destreza involve pushing through your opponent’s sword to attack their body, it makes sense that taller people would have more success with the style, given the above.

I have also noticed that, with some exceptions, most people who practice the Fabris’s fencing style are shorter humans. Given that the Fabris stance leans forward, refusing the lower body, this makes sense.

Practice Yesterday, and Analytics!

Yesterday was a good practice. I spent the day thinking I wasn't going to go because my shin had been bothering me, and because it looked like it was going to thunderstorm. But it didn't! And using a bicycle inner-tube to force my hamstring to stretch actually helped my shin a bunch. Thanks, internet!

So as usual, I collected heart rate data using my fitbit. I fought six different people - first two fights were outside, then the next few were inside.

It's hard to draw straight lines on a phone screen

My first fight was against a shorter, long-time OGR. Those fights were really good. I did not ramp up my speed to 100%, which forced me to focus more on technique. I was trying to fight in a Destreza-ish way and also use the invitation I described last post, which didn't work super well due to how far below me her sword was. Short people with long swords continue to present a problem, especially when my sword is shorter than theirs.

My next set of fights was short single against case. It was a very mobile fight, and it looks like we paused in the middle of the fights for whatever reason. I had to use my mobility to force him to commit one sword, then use my sword to take the other one. Alternately, I had to push his swords together. Alternately, I had to use timing and burst down the center line super-fast. This continues to be an illuminating fight. I also continue to have more success being Fabris-ish against case with single, than being Destreza-ish. I tried to use the invitation thing as a multi-step process to get both of his swords, but it didn't work so well, partly because I have to think to set up the invitation.

My next set was against someone who had been fighting for a year. It went well - he kept surprising me by catching parries when we were in in-fighting range. After a bit, my invitation with my blade to the left stopped working, so I had to change the invitation such that my blade was to the right.

My next set was against a fighter who continually pushes my game to improve. I brought my standard long rapier and dagger against him. You will note that this set and the previous set were the ones where my heart rate peaked. After a certain point I was just exhausted - I couldn't cool off fast enough. I did some cool things with the mirrored invitation with blade to the right, but I think they worked well largely because he expected me to disengage and generally deny blade contact more. I feel like he took more passes than I did, and his game was pretty on-point.

My second-to-last set of fights was against an extremely skilled case fighter. He kept catching me on things that I have been able to deal with in the past, but my brain just wasn't in the fight because it was so ridiculously hot. Very good on him for that. He acknowledged that I seemed tired, and the fact that I couldn't get my heart rate to peak is probably physical evidence of that. So basically, I fought him with my dumb game and didn't use any of my cool new things, and he roflstomped me. I also tried to use mobility to neutralize one of his swords, and it just didn't work.

Plate on the left

My last set of fights was against another extremely skilled case fighter. He also roflstomped me, but I used the guard from Fabris plate 168 against him. Again I tried to use mobility to neutralize a sword, but I couldn't get it to work. I will be trying the mobility thing again against both my last and second-to-last opponent, when I am less tired and overheating. The guard seemed to work relatively well though - I would move in and explode my sword and dagger outwards, hopefully catching one of his swords with each of my instruments. It became a game in which either he was able to counter-punch me, or I was able to catch his swords. I think I need to be even more aggressive about moving forward, and I need to be willing to get into dagger range and dagger-lunge skilled case fighters. He certainly took more passes than I did, but I feel like I have a direction to move, learning-wise.

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It looks worse in person. But it doesn't hurt! So that's nice.

I apparently also took a super hard shot to my hand. After practice I noticed that on my glove and hand. I didn't notice anything super hard, but the nasty bruise on my knuckle and the blown-through kevlar on my glove say otherwise. I now believe that those gloves were worth every penny I paid for them, because that would be way worse if I had not had semi-rigid protection on my knuckles.

That's all I've got for the moment. Tune in next time, for more of the violence-things!

Relating Italian Tempo and Spanish Distance

This post has been sitting in my "Drafts" queue at ~90% completion for a few months. I was inspired to complete it after a post that Doroga made. I have been a bit hesitant to post it, because anything that references Real Numbers is fodder to be disproven by other people. So, take all of this with a grain of salt, and if your numbers end up different from mine, just relax.

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Today, we have a post about tempo, inspired in part by my conversations with Doroga in which we talked about how the Spanish don't really use an idea of tempo, as the Italians do. The Spanish tend to worry more about distance and the appropriate place to do things. Tempo and distance are both important, and both the Spanish and the Italians neglect each other's favorite concepts.

Assuming two identical opponents, it is perfectly acceptable to understand one but not the other. But in modern SCA rapier, we have wide variations in blade type, blade length, and size of humans. I would guess that variation in matchups is much more likely to happen in modern SCA rapier than it would historically, and even in other HEMA-related disciplines. It is to this end that I wish to bring the Italian concept of "tempo" and the Spanish concept of "distance" down to earth.

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On tempo, Capoferro has the following to say on part 50 of his text, in chapter 5 (Leoni's translation):

The narrowest measure requires instead an extra-quick tempo, since even the smallest motion I make with my sword and the shortest stillness of my opponent would be enough for me to reach my design while in this measure; this extra-short tempo is therefore called a half-tempo. The tempo required to strike from the less narrow measure that we would call narrow measure of firm foot is a whole tempo; lastly, the tempo required to strike from the wide measure (which requires [a lunge]) is a whole tempo and a half.

Both before and after this passage, Capoferro speaks as most Italians do about how tempo is the measure of stillness and motion, and how my opponent's stillness corresponds to my motion, and vice versa. All of the Italian masters I have read, when they talk about tempo, speak in those terms. Essentially, it sounds like you and your opponent are taking turns. Why would this be?

Capoferro Plate 11, From Wiktenauer

Humans have a limited reaction speed. ~180ms, or ~1/5 of a second. If you want to perform an action, and be sure it has succeeded, you have to do the thing, then wait for your perceptions to catch up to your movements. This is the way you must act, in order to successfully act, perceive what your opponent has done, and then respond to their action.

This makes sense for the Italians. All of their plates talk about performing an action, and then responding to your opponent's action.

Armed with this knowledge, I took to my swording-dummy and attempted to use Capoferro's definitions of tempo. I have found, from personal experience, that I can lash out my arm to strike an uncovered hand or forearm in about 1/10 of a second. Similarly, a thrust with a lean takes about 1/5 of a second, and a full lunge requires about 3/10 of a second.

This also explains why, against a trained and ready fencer, a full lunge from maximum measure is useless - they can begin their parry after 1/5 of a second, which is enough time for them to disrupt a lunging thrust.

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As for distance, the Spanish have a circle. It's supposedly magical and occult and all of that fun stuff. The particular circle I favor is Viedma's.

From the translation of Díaz de Viedma, Luis. Método de Enseñanza de Maestros [Method of Teaching of Masters]. 1639

Available here.

Viedma provides explicit measurement of the circle, but neglects to tell us exactly how long our sword should be for it. I tend to be more of the Thibault school of things, in which I think all things should be relative. So, Viedma provides us with two measurements - that the circle should be 24 feet around (or ~7.6 feet across, using geometry) and that from point C, you should be able to just stab them with your tip. (For reference, see the Blow of Perfect Attack to the Face, page 22r.) As such, we can calculate that from point C to your opponent should be ~64 to ~67 inches. This means that Viedma is assuming that your sword plus the distance from your spine to your arm will be about that. With my 37" rapier, I hit 68 inches, so that's a bit more than intended by him.

He additionally gives the distance of  a circular step from A to B as 3 feet. Geometry says it's more like 2.9 feet in a straight line, but close enough. That's about how far my foot goes in standard lunge without trying to force it to go farther. This means it probably takes about 1.5 tempi to go that far from neutral, and then another 1.5 tempi to recover after the long step.

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As an aside, I tend to prefer the Thibault philosophy of calculating according to the proportions of the fencer. If I wanted to change the size of the circle, I would take the measurement from spine to tip as the measurement. Then, I would see if the fencer in question could take the appropriate -length step from A to B in the 1.5 tempi of the lunge, possibly widening my stance so that I can cover more ground. If so, great! If not, maybe it's time to use a shorter sword for doing Viedma's thing.

As an aside - using the above method to calculate blade length *does* come up with a correct length, according to Thibault's techniques and ways of moving, which differ subtly from Viedma. For more on historical blade length, see my friend Doroga's post on the subject, and my previous post about daggers.

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So, with that vast bushel of assumptions, we do a number of things. We can see that in the process of stepping, you should be able to perform ~3 single-tempo "actions" with your sword as you move around the circle, from point to point. A step you don't complete contains 1.5 single-tempo "actions", all of which can be defined in terms of Italian "taking the blade", "disengage", "thrust", and so on.

Similarly, one could take different types of steps according to tempo. An Italian non-lunge step takes about one tempo out, and one tempo to recover. Fabris and Capoferro both reference taking even smaller steps as well, though Fabris thinks that this is a poor choice. But, considering that type of stepping, we can decide what we wish to do with our blades, and then calculate what we can commit to with our feet at the same time.

If I were more motivated, one could develop this into a board game, in which people decide what they are doing, then reveal what they did with their previous action, then decide what they are doing with their next action. This would represent the sliding window of reaction-time, in which you are never reacting to exactly what your opponent is doing at this exact moment - you're only reacting to what they did one tempo ago.

If I were even more motivated, I would develop this into a computer game, in which a computer maps out the best option from each location as defined by these equivalencies and the available actions.

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This is, obviously, not the whole story. You can physically move your hand more with a lighter weapon, which means you can perform more blade actions. As well, the body mechanics of different humans will change things - smaller humans can get smaller angles, whereas bigger humans can reach longer angles. But this is the way of the Lupold - over-analyze data from a historical source, and then see if the over-analysis yields any useful conclusions.

Thus far, these equivalencies seem to hold up acceptably. I've been working Fabris, so they are not fresh in my mind, but I might return to them for a bit, to see how things go. There is a post on blade actions mid-step, which would include a brief section on Fabris's forward-movement and sideways-movement with intent. Perhaps I will even write it one day.

Additionally, "tempo" is a term which is not used for a consistent measurement in period sources. Fabris refers to "long tempo" and "short tempo", and I believe the Spanish talk about tempo as not a discrete thing, but as a progressive thing.

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As a summary of this post, with some additional bits that seem correct filled in for good measure:

• A lunge or lunging step is equivalent to 1.5 tempi.
• Recovering from a lunge, forward or backwards, is about equivalent to 1.5 tempi.
• A regular step is equivalent to 1 tempo, and covers half of the space of a lunge
• Similarly, recovering to neutral occupies an additional tempo.
• A tiny step can be taken, occupying .5 tempo in movement and .5 tempo in recovery.
• Longer steps are possible, trading further commitment for further distance, to a point.
• A "blade action" tends to take 1 tempo.
• It takes 1 tempo to react, which means you are always reacting to what your opponent did 1 tempo ago.
• This means that any fully offensive action that takes more than 1 tempo can be defended against.
• Unless you do a tricky thing, like attack when your opponent is distracted or perform a disengage.

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Have a good day, and fence well.

Practice and More Data

Practice went well. I used the Fitbit in exercise mode for the first time at practice, and it was pretty neat! I really wish I had thought to do this during the tournament at Roses, but I didn't. I'm not planning to post this for every practice, but it's a Cool New Data Nerd Thing, and I want to post it at least once.

I am excited by data!

So, let's take this from the top.

My first set of fights were against a fighter who had been gone for a few weeks. They were as close to Maximum Effort as I could do while still trying some of my new Fabris-influenced things. I've found that the rules for single rapier are more universally-applicable than the ones for sword-and-dagger, even when using a dagger - as such, I ended up using those more.

We stopped fighting and bullshitted around some in the middle of our passes, because I was tired and she was probably tired, so there's that dip in the middle of the first set of passes.

After that, there was a long discussion about how to fight a particular class of fighter. I remember getting exasperated at one point, and that's probably the down-tick in my heart-rate in the middle of that rest period.

After that, I fought someone who presents lots of difficulties for me. I realized that either I wasn't presenting my dagger at the appropriate 45º angle to his sword, or I needed to get closer to a 90º angle, or something. I also used my new Fabris-inspired version of my "backwards" stance to perform sword-based opposition in places where I had previously thought it impossible. It was a very educational set of passes, which I will need to think about a lot.

The highest spike of my heart rate came from fighting someone who had requested my 100% Tournament Game. Since I was fighting my 100% Tournament Game, I didn't get a chance to learn anything really. Tournament Game means I make lots of extremely conservative choices, and those aren't the choices I learn from. It was fun though. I realize now how clipped and to-the-point I am when tourney-fighting.

During my last set of fights, I started to wane a bit. I was fighting the best game I could, I really was. But my ability to fight that game was vanishing. I probably should have taken a longer break before those fights, but oh well.

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I like having data, and being able to confirm things about myself using this data. It is interesting to see how my heart rate can go from my resting heart rate of 49 to a peak heart rate of 186. I have heard that Fitbits tend to under-report heart rate data.

If that is true, it is a concern - I should not be going over a heart rate of 190, given that I am 30 years old.

If the Fitbit doesn't report lower than reality, then I am slightly surprised at how low my resting heart rate is.

It's very possible that if the Fitbit is inaccurate, it's inaccurate in a way that isn't strictly linear. It could, say, be reporting 20 bpm too low at rest, and then 20 bpm too high when active. In any case, I don't care as long as it's consistent. And apparently going over maximum heart-rate isn't *that* bad, if you don't already have cardiovascular problems, and if you don't end up significantly over-training.

Oh well. More overthinking.

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That's all I have for the moment.

Roses and Heart Rate

Roses went well. Wil Deth ran the tournament for me so I could fight, and I won it. I fought well, as did my opponents. I could talk about that, but instead I'm going to talk about my new Fitbit.

On Friday, I made an impulse purchase of a Fitbit Charge HR. It's something I have been thinking about for a while, but the actual purchase was an impulse choice. I want to know what my heart is doing. This is partly because I know I have anxiety which negatively impacts my fencing. This is also partly because I have periodic anxiety which negatively impacts me in other ways. Lastly, I have a family history of heart problems, so more data is better.

So, here's my heart rate data from Saturday, when I day-tripped to Roses.

Can you see the tournament in there?

I took a super-hot shower around midnight before going to bed. It looks like I actually got to sleep around 1am. It wasn't a super restful night because my cat was being Very Loud. So, I woke up from my alarm around 7:30 and then got ready and started driving.

We arrived around 12:15 or so, eventually making it to the list around 12:30 to arrange the 1pm tournament. I fought some pickups against Caine, and then sat around some and sipped water before the tournament.

I paid close attention to the monitor on my wrist. The highest heart rate listed here is 154 bpm, but that isn't what it said in-the-moment. Before fights, my heart rate would spike from ~100 bpm to between 145 and 165 bpm. Usually my heart rate dropped to around 120 by the time I got back from fighting and delivering cards, but this cycle kept happening. During fights, my heartbeat was so loud in my ears that I could count it out, and it seemed like I had hit more than three beats per second. According to this data though, I'm not sure if that's the case.

What I need to do is understand better what to do with a high heart rate. I am pretty sure that I tend to fight better when either my heart rate isn't that high, or when I do some prior exercise and my body is actually warmed up to the point that my muscles are keeping up with the resources being provided by my heart.

I've noted that eating, drinking water, and being in cold or cool places tends to drop heart rate. Being in hot places raises heart rate. Anxiety sometimes raises heart rate, and a range of positive and negative emotions drop heart rate.

Next time I fight, I plan to use this data to try to make sure my heart rate matches with how I am exerting myself. The Fitbit also contains other interesting data, like telling me that I haven't eaten enough in the morning and afternoon and letting me know how much I should eat given the amount of exertion I have done in a day.