Archive for the ‘physiology’ Category


#50 – Running a Fever

27 February 2008

Most of the time the word “running” evokes positive thoughts – running with dogs, running on trails, running for fun, running a race, running to be alive.

Notice that “running a fever” is not one of them, nor is “runny nose” or “running to the store to get medication”.  Recently I came down with the flu, apparently for the first time in my adult life because I have never felt so physically miserable before!  Even the low point of my first ultramarathon didn’t feel so bad in comparison.  Also for the first time I had to call in sick at work as my wife and I were both non-functional on Monday.

I awoke that morning after a night of fruitless attempted sleep and staggered down the hallway to the easy chair, where I remained for the next few hours, unable to move.  Despite doing nothing but sitting, my heart rate was around 120 bpm!  More than double my usual resting pulse.  My body was working hard but I wasn’t going anywhere.

Finally I took my temperature and was stunned to see the mercury lined up with 102.5 on the scale!  I drank a couple glasses of ice water and an hour later my temp was down to 101.8 and I was feeling much better.  Another hour went by and the thermometer read 101 flat, which I maintained the rest of the day.

I wonder if my system was overheated due to the fever?  Being unable to thermally self-regulate, an external cooling source (ice water) was required to bring my physiology under control.  The high heat of a fever is beneficial to the immune system and it’s also a more hostile environment for the virus, but apparently 102.5 was borderline too hot for the rest of the body.

Interestingly, according to a fascinating article about exercising in the cold from the bloggers at The Science of Sport, the human body quickly heats up to about 102 degrees during physical exertion.  Maybe running a marathon isn’t quite so different from running a fever after all!

We need look no further than the 2007 Chicago Disaster to realize that 102 degrees of body temperature is very close to our physical limits.  When stressed to the point of being unable to thermoregulate, many marathoners in Chicago required external heat control (such misting fans or ice cubes handed out by spectators) in order to maintain a safe body temperature.

I suppose I could’ve stepped outside into the subfreezing Michigan winter to cool off, but I’ll save my physiological challenges for my foot running not my fever running, thank you.  Besides, hydration is quite important when sick, giving my ice water remedy a double-whammy of effectiveness.

Hydration, thermoregulation, heart rate…  is there any other way to relate the flu with running?  Why of course – body fat.  Two days of no appetite resulted in a net loss of seven pounds, a fat-burning trait that my body would do well to make use of during my next ultramarathon!


#42 – Put Some Elbow Grease Into It

21 December 2007

You wouldn’t believe how hard it is to schedule a physical therapy appointment!  Since my hamstring has been slow to heal I decided I better have someone take a look at it.  I had an appointment for last Tuesday but the trainer called in sick.  No other time slot was available this week and with next week busy with the holidays, I was looking at waiting a long time.

No way.  I wanted to get this leg taken care of – I really miss running!  So I called another branch of the rehab outfit and set up an appointment for first thing this morning.  As I’m eating breakfast I get a call that the trainer at that branch was sick!  I decide to call the original branch to see if I would be lucky enough to find a cancellation.

Even better, almost…  they had me on the schedule for right that minute.  What?!  For some reason I got put on the schedule at both branches at the same time.  If I could leave at that moment, I could get there in time for a therapy session so Amanda and I rushed out the door, I dropped her off at 2 Feet 4 Paws and then buzzed on over to the rehab facility.

The trainer started by testing the strength and range of motion of both hamstrings.  He discovered that my injured right hammy was a bit less flexible, but the strength in it was virtually the same as the left.  After double-checking for any palpable muscle tears, he was able to conclude that my hamstring was not an acute strain but a significant case of micro-tearing.  Basically I overdid the running, which I had guessed was the cause in the first place.

So far, so good – everything was making sense.  He checked out my right knee and hips to ensure there was no related injuries and then started my leg cooking under a heating pad.  Once warmed up he prepared for some deep tissue massage.  Upon hearing this I remarked: “Sounds like fun” to which he replied: “Um, no it might actually be painful.”

HOLY COW!!  Was he ever right – it hurt.  He was actually using his elbow on my hamstring and leveraging his entire weight into the effort.  Ow ow ow, but in a good way.  There was no sharp pain, just a strong soreness, if that makes sense.

After the massage he worked on flexibility.  While lying on my back he grabbed my right foot and next thing you know he’s pushing it up to the ceiling while forcing my knee to remain locked.  It was a pretty tough stretch but not too bad, then he asked me to push down with my leg against his hands.  It’s difficult to apply much force when your muscles are fully stretched out but I got a good push in.

Then he had me stop and relax the leg, after which he stretched it farther up and out!  Yow!  Once again another push against him, relax, and then he stretched it even further!  My foot was in a position relative to my head where I haven’t seen it before.   He asked me to push down again and all my leg could do was tremble.  Finally he put my leg back down and and with that I was done.

I’ll be going back next week for a follow up with instructions to do a lot more stretching in the meantime.  He strongly recommended that I use The Stick so I went out and bought one tonight.  I’ve heard a lot of good things about them and I’ll let you all know how I like it once I get a little more experience with it.

Thankfully my leg was never badly injured and the trainer was confident that I’d be running again soon.  He asked what level of running I wanted to get back to and I told him 20-40 miles per week.   He replied: “OK since it’s winter I’ll just write down 10-20 per week.”  I had to correct him; I run all year round outdoors.  He thought I was crazy enough but when he found out that I’m eyeing a 100K this fall, he flat out called me nuts.  That’s OK – sometimes it’s fun to be a little nutty.


#40 – Frazz Understands

28 November 2007

Back in April the inaugural article on this blog was about heartbeats and life expectancy and it has been one of the most popular posts ever since. The concept that we may have a finite odometer attached to our heart is a fascinating one, and it’s one of the best motivations to get out there and run.

FrazzJef Mallet, the creator of the comic strip Frazz, understands this motivation. Mallet is a devoted endurance athlete and that aspect of himself is projected onto Frazz, the main character in his comics. In the October 28th Sunday edition, Frazz explains why burning up your heartbeats in training can lead to a longer life expectancy.

Does this mean that Mallet was one of the readers of my blog? While I’d love to be a source of anyone’s inspiration, evidence in the Sunday comic indicates that Mallet probably got the idea from an article about the theory of aging by the Santa Fe Institute.

If you haven’t heard of Frazz, check it out, especially if you’re a runner or other endurance junkie. You can probably identify with a lot of topics in the comic; my favorite one I sadly can’t find anymore, but it mirrored a conversation I once had with my brother Ryan that went something like this:

Ryan: Did you go running today?
me: Yeah, but I only did an easy three miles.
Ryan: “Easy” and “three miles” make no sense together!
me: But I was running slowly!
Ryan: “Running” is shooting a layup. Anything measured in miles is too far.

ManateeThe actual Frazz comic is way funnier because it mentions a manatee. I should clarify that Ryan is quite athletic – the only thing he and a manatee have in common is that they’re both intrinsically funny – but he only runs within the confines of a basketball or tennis court. I guess that still counts…


#27 – Are You Wearing Running Genes?

9 August 2007

If you hang around runners and other endurance athletes, sooner or later you’ll hear them talk about “VO2 max”. No, this isn’t what the space shuttle uses for fuel! In a nutshell, VO2 max is a measure of how well your body delivers oxygen to your muscles during prolonged exertion, and thus it’s a good barometer of your endurance capability. I won’t try to explain the science behind it all when someone with an advanced degree can tell you what VO2 max means to runners.

There is also a good VO2 max calculator out there, and many others like it. These calculators are just estimates, but the consensus seems to be that they’re always in the ballpark. An actual test of your VO2 max requires you to spend some time on a treadmill hooked up to an oxygen hose and other instruments; oh, and it’ll cost you $100 or so. Since I don’t have that kind of dough laying around I’ll just stick to the calculators for now. According to the above site my VO2 max is 46.7 ml/kg/min (read the Wikipedia entry on VO2 max to better understand the units of measure.)

A sedentary person will range between 20 and 50 for their VO2 max with an average of 35. In other words, an untrained couch potato can hop off the sofa and test out to the above VO2 max scores. Does this mean that my 46.7 puts me near the top of that range? Not at all! The sedentary VO2 max essentially is your genetic base, a base upon which you can improve with training. VO2 max performance will improve with training – since I’ve been running for almost four years now, I should be well above my base. How far?

January 1, 2004 was my first run since the fall of 1999 and I was well out of shape. I managed to last for 13 minutes, covering just 1.25 miles. According to the calculator my VO2 max was 26.5, although such a short distance doesn’t allow for as much accuracy as a longer run. Still, it shows that my base is quite low! After all my “in shape” score of 46.7 is below what some people can apparently do without even training. Hopefully with further training I can continue to push my upper limit.

Speaking of upper limits, elite athletes can boast some pretty amazing VO2 max scores. The highest ever recorded seems to be a 94 by Bjorn Daehlie, the Norwegian cross-country skier who was almost unbeatable in his prime. Greg LeMond reportedly scored 92.5 and skyrunner Matt Carpenter notched a 90.2 (although he claims that he may have scored a 94.9). You certainly don’t need to score in the 90’s to be competitive; in fact many champion athletes have scores in the 80’s and even 70’s, such as Steve Prefontaine (84.4), Lance Armstrong (83.8), and Frank Shorter (71.3).

Notably none of those elite athletes scored below 50, so I’m not about to earn a living by winning races! If I want to run faster, though, it’ll help to improve my VO2 max as much as I can. The way to do that is to train at or near that limit, which is why runners and coaches recommend interval training – run hard for a minute or few, recover for a bit, then repeat several times. You can’t do this all the time or your body would wear out, but this type of training is what moves your VO2 max upwards. Other aspects also affect endurance – such as lactate threshold and efficient stride mechanics – so VO2 max isn’t the single defining marker for speed over long distances. But it sure helps!

Does this physiology apply to other animals? You bet! In fact you can take that bet to the race track – a thoroughbred race horse has a VO2 max of around 180, twice that of the highest-scoring humans! If that’s not impressive enough, how about the animals curled up at my feet… my dogs. Trained sled dogs scored a VO2 max of 240! Dogs are born to run. Humans not so much, but we still enjoy it! Especially when I’m running with dogs, although sometimes I get a little bit jealous of their genes. 🙂


#1 – Conserve Your Heartbeats

1 April 2007

One of the interesting facts about land mammals is that their life expectancy is the same – if you measure it in terms of heartbeats. All land mammals will live for about 1 billion heartbeats. A shrew has a heart rate of 600 bpm (beats per minute) and a life expectancy of just three years. An elephant with their 30 bpm heart rate can expect to live over 60 years. The hearts of each animal will beat 1 billion times in their expected lifetime.

Humans, of course, are the exception – we can last for about 3 billion heartbeats. I’m not sure why – maybe medical technology, nutrition, who knows. Marine mammals don’t follow the pattern either, but let’s stick with ourselves and our 3 billion heartbeats. There are 525,600 minutes in a year, and the average human has a resting heart rate of 72 bpm, so divide that into 3 billion and you get a life expectancy of 79.3 years.

I was talking about this topic with a co-worker when he asked me “So how many days of your life did you burn up by running that ultramarathon?” Holy cow. My heart rate was probably around 150 bpm for the 12 hours it took me to run 50 miles, so in half a day I used up just over a day’s worth of heartbeats! More than that, I ran for 180 hours total in 2006 – that’s 7.5 days of extra heartbeats spent on running! Is it really worth it?

Before I started running three years ago, my resting heart rate happened to be the average 72 bpm. Let’s assume that I lived my first 28 years at that heart rate, which means I used up 1.06 billion of my life’s heartbeats in that span. Now let’s assume that I keep running (or cycling or otherwise keeping in good shape) for the rest of my life. My current resting heart rate is about 56 bpm, so if I keep that up for my remaining 1.94 billion heart beats, I would live another 69 years… to the age of 94!

By getting into (and staying in) good shape, I increased my life expectancy by 15 years! Each year I spend as a runner costs me one week of heartbeats, but the improved fitness adds 13 weeks to my life expectancy for a net of +12 weeks. Another way to look at it: Every month of regular running adds one week to my life! Diving deeper yet… assuming I run 3.5 times per week, that means that each run adds 12 hours to my life. How’s that for a good investment?

Yes, it’s worth it. Assuming, of course, that my clock will tick 3 billion times…