Sometime in the summer of 2020 GPS 🏃🏻♂️ tracking in the Polar Flow app on my Android phone suddenly started producing crappy results.
Polar shortchanges me by nearly 20%!
Sometime in the summer of 2020 GPS 🏃🏻♂️ tracking in the Polar Flow app on my Android phone suddenly started producing crappy results.
Polar shortchanges me by nearly 20%!
Since 2015, when Christopher McDougall’s Natural Born Heroes introduced me to the work of Phil Maffetone, I have not tried to work on running faster. Instead, I have focused on building a really solid aerobic base. Specifically, I have tried to run at a speed that kept my heart rate near 130 bpm (which was the MAF heart rate I came up with back then).
The theory is that, by training at that heart rate, you will gradually increase the speed at which you can run at that heart rate: You get faster at that particular level of effort. Basically, you persist with that—doing your runs at that heart rate—for as long as your speed increases. Only then do you add speed work (intervals, tempo runs, etc.), and then only as a few percent of your training.
In my own rather casual way I took all that to heart. I never did much speed work anyway, but I was happy to just not do any while I waited for the magic of the MAF system to kick in. But it never did. For the past five years I’ve been running very slowly (call it a 15-minute pace) at a nice low heart rate, but I’ve seen none of the gradual improvement that was promised.
I can’t really call it a failed experiment. I’ve enjoyed these slower runs. I’ve largely avoided injuring myself. I’ve built a solid aerobic base. But I’d like to be able to run faster, and following the MAF system doesn’t seem to have done the trick.
So I’m going to gradually ease back into running faster. I’ve done a little sprinting right along (more as strength-training for my legs than in an effort to work on running faster), and I’ll boost that up just a bit. But the main thing I’ll do is just run faster whenever I feel like it.
For years now, I’ve made it a practice to try to notice when my HR goes above 130, and ease up whenever it does. I might still do some runs like that—it does help me refrain from going out too fast and ending up exhausted halfway through a planned long run. But I think I’ll go back to just intuitively running at whatever pace suits me in the moment.
I did that today, and ran 3.16 miles in 43:16, for an average pace of 13:38. Not fast. But I wasn’t trying to run fast—I just quit deliberately slowing down anytime I noticed my heart rate was over 130. For this run my heart rate averaged just 134, so I wasn’t really pushing the effort. Maybe I can still run 12-minute miles!
(By the way, I wrote about Christopher McDougall’s Natural Born Heroes in a post on it and a few other human movement books.)
A little hiking in the woods gets me a very nice Oura ring activity score. #oura #ouraring
I’d heard this, but I’m not sure I really believed it.
I’ve been running in “barefoot” shoes for a good 5 years now. The improvement in my gait was dramatic and immediate. But serious barefoot advocates are very firm about the point that it’s only when you run with actual bare feet that you acquire the huge upside that comes with barefoot running.
Reduced injury rates (due to the improved gait) are one of those upsides. Increased running efficiency (due to the improved gait, but also due to not having to carry the weight of a shoe on each foot) is another upside.
But there are alleged to be further sources of improved efficiency that come from barefoot running. When you’re actually barefoot, you’re going to hit the ground much more gently (because without cushioning it would hurt to hit the ground hard). Your foot is going to hit the ground with zero forward velocity (because if your bare foot slides along the concrete, the friction will cause blisters almost immediately).
In both cases—not slamming your foot into the ground, and not grinding your foot into the ground—the upshot is improved efficiency.
But it’s one thing to hear that “improved efficiency” is a thing, and another to actually see it. Check out this comparison of a run from one month ago, versus a run today.
Here’s the first three-quarters of mile of a run from one month ago, wearing minimalist shoes:
I left off the first few tens of seconds because it took until then for my heart rate monitor to stabilize on my actual heart rate. Then I went on for about three-quarters of a mile (out of a longer run) to match the distance that I ran today.
The things to note are that I ran at a 14:20 min/mil pace (very slow), that my heart rate averaged 117 bpm, and that the majority of my run was spent in zone 3.
Now check out my graph from today’s run, run with actual bare feet:
I’ve matched the distances (the former is the first part of a much longer run, the latter my entire barefoot run today). Today’s run was at a considerably faster pace (37 seconds per mile faster), while at the same time keeping my heart rate considerably lower (averaging 109 bpm, entirely in zone 2).
I have to say, this is very promising for future endeavors. I need to boost my confidence a bit, so I feel comfortable going for longer runs barefoot. I also need to get a bit more familiar with pacing—my MAF heart rate is probably more like 124. I need to figure out what it feels like when I run that pace barefoot. Because: who knows how fast I can run at that heart rate barefoot?
(The shortcode below won’t work until I get an updated version of the plugin for displaying GPX maps.)
“Google Fit on my phone thinks I need more movement too. But I don’t let it push me around.” –@jackieLbrewer
On Sunday I ran in the Rattlesnake Master Run for the Prairie 10k.
Usually I expect that I’ll write a post when I participate in an event like that, but it turns out that I don’t have a lot to say about it. It went fine. I ran very slowly, which I expected because I’d done all of my training very slowly, but I did not come in last, which was nice.
I’d suffered with a nagging sore foot for several weeks leading up to the race. The pain was in the heel of my right foot, which made me figure it was probably plantar fasciitis. I think I’ve figured out though that it’s actually peroneal tendonitis. Understanding that gives me a clue toward recovery. The peroneal tendon, which reaches down the outside of your ankle, through the heel, and then forward across to the inside edge of the front of your foot, is heavily involved in balancing, especially standing on one foot. I do a lot of single-leg standing as part of my taiji practice and teaching, and since figuring this out I’ve been especially careful about being gentle with myself in this part of the practice, and in just a few days I’ve finally seen dramatic improvement.
The realization didn’t help in time for the race though, and my foot was a little sore right along. It wasn’t so sore that I thought I was doing real damage though, so I just ran the race anyway. It did impact my gate a bit, which meant that my opposite-leg knee started hurting about halfway through the race.
Part of the reason for this post is to test the GPX exporting at Polar (which had been broken for a while) and the GPX tracking plug-in that I’ve got here (which has been updated a couple of times since I last successfully got a GPX track exported from Polar). So, here’s the track of my run. The heart rate data doesn’t seem to be working.
(I didn’t want to fiddle with my phone at the start or finish of the race, so I started tracking my run about 5 minutes before the start of the race, and then I forgot to turn it off until about 5 minutes after I crossed the finish line, so both the time and the distance are a little off.)
It was pretty cold at the start—cold enough that I didn’t manage to get my race number in my pre-race selfie:
It had warmed up a lot by the end of the race, when I captured the selfie up at the top with Jackie (who along with a lot of the Master Naturalists had volunteered in the race).
For an article in the New York Times, technology writer Brian X. Chen wore a sleep-tracker for a couple of weeks. He reports:
Ultimately, the technology did not help me sleep more. It didn’t reveal anything that I didn’t already know, which is that I average about five and a half hours of slumber a night. And the data did not help me answer what I should do about my particular sleep problems. In fact, I’ve felt grumpier since I started these tests.Source: The Sad Truth About Sleep-Tracking Devices and Apps
Breaking news: Looking at your power bill every month does not cut your electricity consumption! Checking your speedometer does not slow down your car! Tracking your spending does not make you rich!
I’ve been using a sleep tracker (the Oura ring) since December. Neither wearing the ring nor checking the reports I get has increased the amount of sleep I got. However, I have learned a lot about how to get more and better sleep.
Probably the most useful thing I’ve learned is that the standard advice that you should have supper at least three hours before bedtime isn’t sufficient for me: I sleep much better if I finish supper at least four hours before I lie down to go to sleep.
That’s actually a specific example of my larger point: A sleep tracker makes it easy to run little experiments and quickly see the results.
My intuition as to whether I got a good night’s sleep is an excellent guide (as I suspect it is for most people). But even a good intuition isn’t always enough to run a good experiment, and this is an example of that. Although the Oura ring’s report isn’t better than my own intuition, it provided some specific information that led me to that particular insight: On days when I had a late supper, my sleep quality was quite poor for the first couple hours of sleep, a pattern that I didn’t see on days when I had an early supper.
I’ve used it to run other experiments. For example, it appears that I get more deep sleep on days when I have only one drink than on days when I have two. (This is very sad news, and will have to be confirmed by many more experiments before I use it to modify my behavior—but at least I can run the experiments.)
After a rough patch last fall (which is what prompted me to order the Oura ring), I’m actually sleeping pretty well now, so I’m not aggressively running new experiments to try and improve my sleep. I am, however, paying attention when a natural experiment presents itself. For example, we generally sleep with the windows open all summer. Over the next two nights that will probably produce sleeping temperatures in the 70s, whereas over following several nights I’ll get to enjoy sleeping temperatures in the 60s. I know from experience that the cooler temperatures will produce better sleep, but the Oura ring will give me detailed metrics that will let me investigate if there’s an optimal temperature—information that may be very useful in the winter for deciding how to adjust the thermostat.
That’s the value of the ring for me: It lets me run experiments of specific sleep interventions, and gives me results that are more fine-grained than just a general sense as to whether I slept well or not.
Here’s one more natural experiment. I observed decades ago that I need more sleep in the winter than I do in the summer. I can now put a couple of numbers on that.
Here’s my total sleep each day in January and February this year. The report from the Oura ring lets me see that I averaged 7 h 50 min of sleep each night:
Here’s my total sleep each day from June 1st through last night. I can see that I averaged 7 h 03 min of sleep each night:
I’ve perceived each period as being roughly equally good in terms of getting “enough” sleep, so I’m inclined to think of the 47 minute decrease in sleep as being a decrease in the amount of sleep I need when the days are long and sunny and I’m getting plenty of fresh air and exposure to nature. In the winter I need darn near 8 hours of sleep per night. In the summer I can get by fine on just over 7.
That information doesn’t make me sleep better, but it’s still useful (even if it just confirms something I’ve known for a long time).
In other breaking news recently published in the science journal “Duh!”: Stepping on the bathroom scale every morning neither increases your muscle mass nor reduces your fat mass!
HRV (Heart Rate Variability) is one of the metrics that the Oura ring tracks. I’ve begun to learn a bit about it, and thought I’d share what I’ve learned so far, and then share a small personal observation.
Very briefly, HRV has to do with the variations in the timings between heart beats. If your heart rate is 60 beats per minute then about one second will pass from one heart beat to the next—but only about one second. In actual fact, sometimes it will be a few milliseconds more, and other times it will be a few milliseconds less. Those “more or less” amounts are your heart rate variability or HRV.
Most of what I know about the HRV comes from an interview on Human OS Radio podcast with Phyllis Stein, Director of the Heart Rate Variability Laboratory at the Washington University School of Medicine in St. Louis, called Introduction to Heart Rate Variability (HRV). It’s definitely worth a listen, if you do the podcast thing.
A lot of HRV is related to respiration. I noticed this when I got my first heart rate monitor thirty years ago: Every time I inhaled my heart rate speeded up, and every time I exhaled my heart rate slowed down. This effect is pronounced enough that the Oura ring can calculate your respiration rate just by watching your heart rate speed up and slow down with each breath.
HRV is widely used as an indicator of the balance between your parasympathetic and sympathetic nervous systems: If your parasympathetic nervous system is functioning well you’ll see quite a bit of variation. When it’s not functioning well—for example, when you’re persistently stressed—the amount of variation in your heart rate will decline.
Since I got my Oura ring, I’ve been tracking my HRV, looking to see if this or that bit of self-care practice will increase it, and I’ve noticed one thing that seems kind of interesting: Very often my HRV will be quite low in the first half of the night, and then be higher (and with higher variability in the variations) in the second half of the night. Here are three recent examples:
I speculate that this is related to the fact that I’m still digesting supper at bedtime, or perhaps that alcohol I’ve consumed is not fully metabolized yet. I’ve been hoping that life would produce a natural experiment to test those two theories, but so far haven’t gotten one. (That is, days when supper or cocktail hour were very early or had to be skipped have also been days when some other factor—such as illness, an unusual bedtime, or unusual stress—confounded things such that I couldn’t really draw any conclusion about the effect on my HRV.)
First, let me say that maximizing my Oura ring activity score is, in and of itself, of no value whatsoever—except to the extent that it reflects and reinforces my efforts to get an appropriate level of physical activity.
Happily, I find that getting an appropriate amount of activity generally results in a higher score. So it works at that level, with perhaps a few mismatches between what I think is appropriate and what the Oura software thinks is appropriate, the main one being their idea of what counts as a recovery day.
Periodization of training—getting a mix of training days and recovery days—is a great idea. In fact, the lack of periodization is one of the limitations with Google Fit, whose model is to have a daily activity goal which is a little aggressive—a goal that motivates you to to get out and walk just a little more than you otherwise might. The problem is that a goal that’s even a little bit aggressive is going to be excessive for your recovery days, while still being much less than you probably want for your training days.
This is where the Oura ring software is a big step up from Google Fit. It strongly encourages both training days and recovery days. Unfortunately, its idea of a recovery day seems a bit too strict for me:
For Oura, an easy day means keeping the amount of medium intensity level activity below 200 MET minutes (200-300 kcal/day), and high intensity activity below 100 MET minutes (100-150 kcal/day).
In practice this can mean doing lots of low intensity activities, getting healthy amounts of medium intensity activity (30-60 min), but only a small amount of high intensity activity (below 10 min).
Now, that’s all well and good, except that ordinary walking is a medium intensity activity, and (except when the weather is crappy) it’s a very rare day indeed that I don’t end up walking more than an hour—meaning that I basically never get a recovery day in Oura ring terms.
The result is that whenever the weather is nice my activity score starts dropping, because I’m not getting what my ring thinks is appropriate recovery. Then, when there’s a couple of days of crappy weather and I sit around the house all day, my score will climb (as my recovery time value improves). Then, as soon as the weather gets nice again and I can get out and be active, my activity score can shoot up into the high 90s:
However, I can only get five days of such high levels. Since I need to have at least two recovery days per week, a string of more than five nice days means my recovery suffers once again, turning into lower activity scores.
I haven’t fully characterized the behavior so far, but it seems like the software may well be doing just what the quoted text above says: Getting between 30 and 60 minutes of medium activity makes a day a recovery day, with a hard end to any “recovery” at 61 minutes.
If true, that would probably be the place to make a fix. That is, I’m not trying to suggest that I have any data to show that an average person could walk more than 60 minutes and still recover as well, nor do I have any good metric for identifying some subset of people who can walk more and recover well. But I am pretty sure that the 1 h 3 min of medium activity that I got the day before yesterday is not so much more than the 60 I got yesterday that the former should count as a training day rather than a recovery day.
As a big ol’ data geek, I’m by default interested in any metrics that I can get, especially ones related to me.
One of the metrics tracked by the Oura ring is body temperature, which is a metric don’t normally pay much attention to unless I think I might be sick, and I haven’t wanted to get sick just to explore this feature of the Oura ring. But a couple of days ago I did something much better: I got my shingles vaccination.
(I’ve been trying to get my shingles vaccination for months now, since they changed the recommended age from 60 to 50 and my insurance company started covering it for young folks like me. But with all the younger boomers thinking the same thing, the vaccine became scarce. Jackie and I finally tracked down shots last week.)
My immune system viewed the shot as something of a stern challenge, and sure enough my body temperature became elevated. In the graph below observe the last three data points, which show a spike to 0.7℉ above my baseline, followed by a 0.6℉ elevation the second night. Last night was only 0.3℉ above the baseline and back down in the normal range. (Near the middle you can see another spike to 0.7℉ above baseline followed by a negative deviation of a similar amount. That excursion was, I think, related to life stress.)
Observing that I was under some stress, the ring has been advising me to take it easy for the past couple of days. Knowing that the stress in question was a healthy one, I didn’t take the warning too seriously. The weather was nice the day after the shot, so I went out for a run, despite my ring’s advice.
Despite disregarding that particular day’s advice, I’ve actually been paying rather close attention to the ring’s indications as to my readiness. For example yesterday, when my body temperature and other factors suggested that I was still not recovered, I did take it easy—and I have been rewarded with an excellent night’s sleep and a moderately high readiness score for today:
Perhaps today will be a good day for a long walk. By the middle of the week we’ll have some more excellent running weather, and hopefully I’ll be ready for it.