Tracking heart rate while running in Bangkok heat

 

I'm not sure who a run training update would be interesting for or helpful to, which is why I don't write these very often.  I'm not sharing results on Strava or anything like that either, racing, or running with friends, so I just keep doing it to exercise, as my own thing.

Trying out tracking heart rate is the newest thing.  I suppose what seemed like a minor injury back in October or so had been the newest thing earlier; I never knew what to make of that.  A knee issue seemed inconsistent, as if tendons were sore in different places, maybe moving around because the real cause of the problem was elsewhere, a glute or hip stabilizer muscle issue.  Who knows what it was.

After resolving that through rest and time off, and building moderate intensity weekly mileage back up, to about 30 km per week now, I tried out using a very basic heart rate monitor.  

It's not so uncommon for people to use low heartrate training as a main approach, to calculate some relative low-intensity optimum, and then instead of running miles or km at a set pace to keep heart rate consistent.  That was never the plan; I was mostly just curious what it was.  It seemed interesting to be able to see how heart rate varied with pace, and effort level, and if heat stress seemed to be affecting that factor.  Then later maybe it could be a factor in changing approach.

It all worked out as one might expect; a very moderate running pace corresponds to 130 to 135 bpm, and running at higher intensity and a faster pace tops out around 145 to 150.  It seems that related to pace the window spanning the two is not that far apart.  It takes me a lot of effort to run 6 minute kilometers now, even though I had trained to run some of them between 5:30 and 5:45 a year ago.  That was in Honolulu, Hawaii, where it's cooler, with some elevation change on my normal route.  There I could run the 11th and 12th consecutive kilometers at 5:45 on a warm afternoon along a flat course, and in slightly warmer local Bangkok weather now that would be hard.

running alternate intensity 10k at 30 C (86 F)

These both show a new form that I'm trying out, running an easy 5k followed without break by a higher effort, faster 5k.

There isn't all that much training theory behind that.  It combines easing into a session and sustaining some higher intensity running.  The humidity and temperature shift how that kind of thing goes; at a hotter and more humid time maintaining "low" heart rate (135) even at the moderate pace wouldn't work.  It's essentially always in the mid to upper 80s F / upper 20s C in Bangkok, unless you run at 6 AM, and since I'm not a morning person I just try to avoid the low 90s / low to mid 30s C.  I can show how that goes in another stats capture, but I'll add a little about how this workout version shown in graphs feels first.

Running at 135 bpm is fairly relaxed, if it's only 29-30 C, mid-80s F.  I don't know if that's a good or a bad thing; it's my impression that pacing depends on a base level of conditioning, which I'm not qualified to interpret.  It's probably not good or bad, instead just where you are at the time.

Running between 145 and 150 bmp isn't so stressful, but that's as far as I'd want to push it, and sustaining that general level for 5k seems like enough.  In the past I would feel a slight breakdown of my normal equilibrium, energy level, and breathing rate, right towards the end of what I had trained to easily do, and that often related to running 10k in about 1:01 to 1:02, a minute or two faster than using this approach.  That kind of minor difference stands out a lot; running a 30 minute 5k and a 32 minute pace is completely different.  That's the difference between a 6 minute km and a 6:25; it's vast.

I can switch the units, in case someone reading this runs at min / mile:  that's a 9:40 versus 10:20 mile pace (6 to 6:25 min / km).  Again whether that is fast or slow depends on someone's conditioning level.  Anyone routinely training in much cooler weather probably wouldn't tolerate the heat input part of it well, running at 85 to 90 degrees F, regardless of their normal pace.

I always thought it would be easier to train to run faster, much earlier on.  I could break 20 minute 5k race times in high school cross country, and I wasn't all that good a runner, and didn't train that much.  It turns out that running a 4 minute km / 6:26 mile isn't easy to do at age 55, without prior "training up" to that fitness level.  

I had been experimenting with running shorter intervals faster when that odd injury came up, which is probably no coincidence, so in order to avoid that experience I'll have to forego that most natural training approach to drop those times.  If I add some weight training I might become more durable, but I'm not eager to expand training range like that.  I had been walking and swimming more a year or so ago when I managed to push both intensity and volume past where it is now; maybe those really did help with recovery, muscle training, or general conditioning level.

heat impact example; running 7+ k at 31 C (88 F), in the mid-day sun

The other question I had related to the impact of running when it's hotter, when it's not in the mid 80s, but around 90 instead.  A recent outing tested that:

It really wasn't that hot; on that first run it was 30 C, 86 F, and on this second it was 31, 88 F.  The first was in the evening, after dark, and this was in mid-day sun, running between noon and 1 PM, and it really makes a difference.  Of course it does, as humidity level and breeze does (or lack of it), but I mean that you can have a completely different kind of experience, not that it's a noticeable slight change.  

47% humidity is on the dry side for here; I suppose that helped, but running in direct mid-day sunlight was a more problematic negative input.  Those temperatures I've cited are some central Bangkok measurement; I was probably experiencing a broader gap where I actually was, out on a running track / sidewalk environment.

On one running course I complete two 5k laps, with no second warm stretch, and on this route I do either 2 or 3 3.7 km segments, with a warm stretch after 1 km.  On that second heart rate dip (above, during km 6) I was walking to rest, to drop my heart rate, which had been pegged at or near 150 the whole time.  I think that tied to heat stress input, but I haven't fully sorted out other possible variables.  It's easy to write off having any rough outing as heat input, but there's probably more to it.

a track / path around the local royal palace

that running path at night, lit up for some holiday or memorial theme

what it looks like in the daytime

One might wonder, how is this informative or actionable, beyond prompting me to try out that split-pace approach?  I suppose it's not.  I could've felt that the second run described here wasn't going as well without a heart rate stat filling that part in, that I was hot.  I was averaging 6:15 km paces, just not on the two one-km splits with a stretch and walking break, so it wasn't really fast or slow, but it was taking effort to do that.  The second 5k of that earlier run was slightly faster, right on 6 minutes / km instead, at significantly lower heart rate, just below 145 average instead of close to 150.  You can feel that difference.

It's a different thing running against conditioning level versus pushing heat stress tolerance.  You feel a bit tired after an hour of medium intensity running, but that heat stress stays with you, even when only enduring 40 minutes worth of it.  I won't do hour long outings when the heat is getting to me; I could back way off a normal pace and tolerate it better (maybe; I never really try running 7 minute km pace), but it's habit to just stay in a normal pace range and call it a day early.  If I feel off I'll run 6:30 kilometers but beyond that I tend to just pack it in.

Trying out tracking heart rate was only ever about sorting out these patterns, which I had already experienced without tracking that.  I can run a 6 minute km, or 6:30, by feel, even with outdoor temperature input factoring in.  It's odd that the one is such a fast pace for me and other slow; that distribution could be broader.  I think with less heat-stress for running context, actually running when it's below 80 F / 27 C, I could train differently, and make better progress.

In Honolulu now, a daytime high of 78, breezy, with a chance of light rain.  Perfect!

the view running around Diamondhead; pretty nice