Heat Index

Sikochi

Maximum Pace
Sep 13, 2010
1,181
76
68
Kochi
#1
After struggling on yesterday`s ride and failing to complete what I intended for the first time this year due to the heat (partly my fault, as I didn`t appreciate quite how hot it was so didn`t go with my coolest possible top options as it means no pockets), I was searching for info on how humidity and heat combine. I came across this thing called the heat index, which for those who don`t know, factors the humidity in with the heat to create a more accurate representation of the actual heat.
from Wikipedia
`The heat index (HI) is an index that combines air temperature and relative humidity in an attempt to determine the human-perceived equivalent temperature`
http://en.wikipedia.org/wiki/Heat_index
some other links
http://www.crh.noaa.gov/pub/heat.php
http://www.weather.gov/om/heat/index.shtml
so basically, given a temperature of 31C and 70-75 humidity, I was trying to do L4 intervals at around 95-100F (Sunstroke, heat cramps and heat exhaustion possible) Oops. Looks like I will have to adjust plans and settle for summer base phase.
proxy.php?image=http%3A%2F%2Fwww.crh.noaa.gov%2FImage%2Fpub%2Fheatindex.gif&hash=527fc90969f632b7c0c3c488d06d81cd


edit: These sites allow you to work out the relative temperature:-
http://www.srh.noaa.gov/epz/?n=wxcalc_heatindex
http://www.hpc.ncep.noaa.gov/html/heatindex.shtml
Be careful out there!
 

StuInTokyo

Maximum Pace
Dec 3, 2010
1,662
62
78
#2
All very true!!

Today, I think because it is windy, the humidity is only 50% according to JMA, so that means at 32.3C and a RH of 50% it is like 37C out there..... yeah hot, but if it was the same temp and 80% RH it would feel like 49C :eek: Bloody hell!
 

FarEast

Maximum Pace
May 25, 2009
5,528
538
193
Yokohama
#3
Guys be careful last year there were several deaths in the cycling community here in Tokyo and no doubt more elsewhere due to heat stroke.

If you ar out on your own in the middle of nowhere or even with a group of riders getting immediate medical help isvery slim.

Its why many of us switch to Asaren or Yoruren durring the hot months.
 

jdd

Maximum Pace
Hardest Crash
Jul 26, 2008
2,519
650
133
Kanazawa
#4
Thanks, FE, I hadn't heard 朝練, instead using 早朝, which I had heard used for some early a.m. baseball players that I ride by.

Besides lower temps, there's far less wind and traffic, generally no bugs, and the air smells great. (And zero keystones, usually making red lights a slow pause instead of a wait).

***

And I guess I've been away too long, ºF in that chart seems hard to figure out. As a donor, I'd appreciate it if wikipedia were more proactive on U.S backwardness.
 

timdesuyo

Speeding Up
Mar 29, 2010
138
1
38
Tokyo
#5
How ever you measure how hot it feels, I drained my 750mL bottle before I even got to the immigration office this morning. Gyah!
 

StuInTokyo

Maximum Pace
Dec 3, 2010
1,662
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78
#6
.......And I guess I've been away too long, ºF in that chart seems hard to figure out........
I'm old enough that I was taught both at school in Canada, but for temps I know that 72F is room temp, 32F is freezing, and 105F in the shade is freaking hot! :eek:

I cannot help when I do deliveries, usually from about 3PM to 6PM so it is hot and the roads are busy. The wind helped a bit with the humidity, but man it was blowing me sideways!!

I'm most of the way through my second 2L bottle of water today! :warau:
 

GSAstuto

Maximum Pace
Oct 11, 2009
945
242
103
tokyo
www.roadfixie.com
#7
There was extensive discussion on hydration etc from last year. As always make sure you are well hydrated BEFORE you ride. And drink often during the ride. The electrolyte tabs like High5, etc are very very welcome! As you can pop them into any water source if you feel you are getting a bit too hypotonic.
 

Sikochi

Maximum Pace
Sep 13, 2010
1,181
76
68
Kochi
#8
I'm old enough that I was taught both at school in Canada, but for temps I know that 72F is room temp, 32F is freezing, and 105F in the shade is freaking hot! :eek:
QUOTE]

We use both concurrently in the UK but I think it is more due to the fact that in the summer, temperatures sound higher in Fahrenheit (in the 80`s) than when using Centigrade (in the upper 20`s) whereas in winter -2/-4 when using Centigrade sounds colder than Fahrenheit (mid-20`s)
 

Sikochi

Maximum Pace
Sep 13, 2010
1,181
76
68
Kochi
#9
There was extensive discussion on hydration etc from last year. As always make sure you are well hydrated BEFORE you ride. And drink often during the ride. The electrolyte tabs like High5, etc are very very welcome! As you can pop them into any water source if you feel you are getting a bit too hypotonic.
Yes, hydration is vital but it is important to remember there are other things you can do to minimise heat stress. I just went wrong on Thurs as it wasn`t that hot here due to the wind (blew over the washing pole) but when I hit the mountain, the wind disappeared, forgot to account for the humidity, steepness of grade was an issue, the sun came out on the exposed sections, sub-optimal choice of clothing, riding in middle of afternoon due to teaching later and as a result my body wasn`t able to cool itself sufficiently to cope with the level of effort I was asking it to perform. But a better strategy would have helped and prevented over-reliance on my body`s cooling mechanism which wasn`t up to the task.

So today`s ride, I left later but temperature was same as Thurs due to it being hotter: about 30C, 75% humidity when I left (97F relative temp).
But
1) cooled myself before I left (same hydration as Thurs, but added salt to water)
2) best clothing options - best wicking socks, Craft cool boxers, Craft cool base layer as top, Pearl Izumi arm coolers, old gloves that have holes over the palms (apparently, you have the highest concentration of sweat glands on your palms)
3) choice of route - went with long mountain climb 16.4K/670m, but offers a lot of shelter with few exposed sections and lower gradient means higher average speed so more benefit from the breeze you generate from cycling
4) drank more regularly

upped the pace after 10 mins (flat/rolling section before climb starts) to see how long I could sustain and was fine for 35 mins, then had to back off a bit, but after 5 mins the cooling effect from being at a higher altitude (here, 300m seems to be a noticeable point) kicked in and upped the tempo again and was fine and at top, was only 4 mins slower for the section I did the full-out effort on last week (58 vs 54)

Anyway, some other possible heat strategies:

start at higher altitude, or ride the lower slopes at a lower effort level, then pick up the pace once you get higher up.
use ice/ice packs
tailwinds/headwinds - plan route so hardest section is into headwind for maximum cooling effect.
douse yourself in water and/or set off in wet clothing!
 

Phil

Maximum Pace
#12
Growing up in the UK we never heard of the heat index either until moving to central Canada, which gets pretty humid in the summer...although nowhere near as bad as Japan!

For comparison, it hit 32 C or so here in LA the last week, and it felt like mid-May in Japan, perfectly comfortable. No humidity here, although everyone has been giving me dire warnings about how hot it gets in the summer... We shall see. :)
 

zenbiker

Maximum Pace
Mar 4, 2008
802
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63
Chofu
#13
Just how effective are things like cool base layers and arm coolers? Do they actually make you 'cooler', or do they just wick sweat away?
The Pearl Izumi UV covers work a treat. They stop you burning and do actually make your arms feel cooler!
I also have the Assos UV cut arm covers which are crap!:mad:
 

Sikochi

Maximum Pace
Sep 13, 2010
1,181
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Kochi
#14
Just how effective are things like cool base layers and arm coolers? Do they actually make you 'cooler', or do they just wick sweat away?
Saturday with the Craft cool base layer and arm covers was noticeably cooler. As I mentioned on the June thread, on Sat got absolutely drenched in a complete deluge on the way down the mountain and when I got to the bottom - temp had lowered to 22C - actually felt like I wanted a hot drink. Once the top/arm covers get wet (either water or sweating) they do seem to cool you down, so not just wicking sweat away. And I would rate the Craft top as the nicest I have worn once it gets sweaty - no feeling of discomfort. Also, I needed to take on board far less liquid on Sat, than Thurs, despite it being a far harder ride. I think I shall order some more to wear as general base layers.

Also, the arm coolers and cool top are both UV protective, so no need to bother with sunsceen. They also offer some skin protection should you fall off!
 

StuInTokyo

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Dec 3, 2010
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#15
Being a skin cancer survivor, I worry about this stuff and I hate the greasy oily suntan lotion, so the UV cut arm covers are great!

I got some from Y's road they are called N-Rit they come in black or white, and they are only 1400 yen each, and they do work, keeps me cool as well. :D
 

Sikochi

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Sep 13, 2010
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Kochi
#16
Being a skin cancer survivor, I worry about this stuff and I hate the greasy oily suntan lotion, so the UV cut arm covers are great!

I got some from Y's road they are called N-Rit they come in black or white, and they are only 1400 yen each, and they do work, keeps me cool as well. :D
I`m very hairy, so it`s a pain in the arse applying suncream. Anyway, what is it with this black, cool UV stuff? Someone please explain...
 

StuInTokyo

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Dec 3, 2010
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#17
I`m very hairy, so it`s a pain in the arse applying suncream. Anyway, what is it with this black, cool UV stuff? Someone please explain...
They are arm covers, they look like arm warmers, but they are super thin and they wick away the sweat from your arms, which when it evaporates cools you off. They are rated at SPF50.

There are various kinds out there, most are expensive, I bought the cheap ones to see if they work, and they have worked well for me. I have the white ones too, but they get dirty so fast, the black ones don't look so dirty so quickly I wear them at work, doing deliveries under regular t-shirts etc.

Here is a >> LINK << :D
 

snoogly

Maximum Pace
Oct 14, 2007
695
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48
Machida, Tokyo
#18
This belongs as much in the 'Today ..' thread as this one, but ...

Does anyone have any recommendations for 1 liter water bottles? They seem to be rarer than hen's teeth.
 

Sikochi

Maximum Pace
Sep 13, 2010
1,181
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Kochi
#19
Cheers Stu, but I meant why use black for cooling, seems counter-intuitive to me? :confused: Unless white clothing, as well as reflecting back some of the sun`s heat, also reflects back some of your own body`s heat as well.
Whereas the black absorbs more of the sun`s heat, but also your own as well. Which is ok, as then the wicking effect comes into play, and removes it???
 

StuInTokyo

Maximum Pace
Dec 3, 2010
1,662
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#20
Cheers Stu, but I meant why use black for cooling, seems counter-intuitive to me? :confused: Unless white clothing, as well as reflecting back some of the sun`s heat, also reflects back some of your own body`s heat as well.
Whereas the black absorbs more of the sun`s heat, but also your own as well. Which is ok, as then the wicking effect comes into play, and removes it???
Yep, I agree with your thinking, which is why the first set I bought were white, but they got dirty really quickly, so the second set are black. I should wear one black one and one white one and see if I can feel a difference :D