Perceived Temperature For Runners Version 2

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This chart shows the perceived temperature while running based on a specific height, weight and pace. This calculator is based on my Running Heat Model.

Contents

1 Introduction

Normal heat indexes assume a person walking outdoors at 3 mph and generating 180 watts per square meter of skin. The original work states "higher levels of activity would increase the sensitivity to humidity… few people, however, sustain activity above the level considered here for long enough to reach a steady state". This is not very helpful to runners that are moving far quicker than 3 mph and generating a lot more heat.

2 Heat equivalent table

The table below shows an example set of equivalent temperatures for someone running 8:00 min/mile pace and is 174cm/70inches high and weighs 60Kg/132lbs. You can create a customized version of this table by filling in the form below

0%10%20%30%40%50%60%70%80%90%100%
0f/(-17.8c)19.8f
-6.8c
737w lost
19.8f
-6.8c
737w lost
19.8f
-6.8c
737w lost
19.8f
-6.8c
737w lost
19.8f
-6.8c
737w lost
19.8f
-6.8c
737w lost
19.8f
-6.8c
737w lost
19.8f
-6.8c
737w lost
19.8f
-6.8c
737w lost
19.8f
-6.8c
738w lost
19.8f
-6.8c
738w lost
5f/(-15c)26.6f
-3c
652w lost
26.6f
-3c
652w lost
26.6f
-3c
652w lost
26.6f
-3c
653w lost
26.6f
-3c
653w lost
26.6f
-3c
653w lost
26.6f
-3c
653w lost
26.6f
-3c
653w lost
26.6f
-3c
653w lost
26.6f
-3c
653w lost
26.6f
-3c
653w lost
10f/(-12.2c)33.4f
0.8c
568w lost
33.4f
0.8c
568w lost
33.4f
0.8c
568w lost
33.4f
0.8c
568w lost
33.4f
0.8c
568w lost
33.4f
0.8c
569w lost
33.4f
0.8c
569w lost
33.4f
0.8c
569w lost
33.4f
0.8c
569w lost
33.4f
0.8c
569w lost
33.4f
0.8c
569w lost
15f/(-9.4c)40.2f
4.6c
483w lost
40.2f
4.6c
484w lost
40.2f
4.6c
484w lost
40.2f
4.6c
484w lost
40.2f
4.6c
484w lost
40.2f
4.6c
484w lost
40.2f
4.6c
485w lost
40.2f
4.6c
485w lost
40.2f
4.6c
485w lost
40.2f
4.6c
485w lost
40.2f
4.6c
485w lost
20f/(-6.7c)47f
8.3c
399w lost
47f
8.3c
399w lost
47f
8.3c
399w lost
47f
8.3c
400w lost
47f
8.3c
400w lost
45.2f
7.3c
400w lost
45.2f
7.3c
400w lost
45.2f
7.3c
401w lost
45.2f
7.3c
401w lost
45.2f
7.3c
401w lost
45.2f
7.3c
401w lost
25f/(-3.9c)52f
11.1c
314w lost
52f
11.1c
315w lost
52f
11.1c
315w lost
52f
11.1c
315w lost
52f
11.1c
316w lost
52f
11.1c
316w lost
52f
11.1c
316w lost
52f
11.1c
317w lost
52f
11.1c
317w lost
52f
11.1c
317w lost
52f
11.1c
318w lost
30f/(-1.1c)58.8f
14.9c
230w lost
58.8f
14.9c
230w lost
58.8f
14.9c
231w lost
58.8f
14.9c
231w lost
58.8f
14.9c
232w lost
58.8f
14.9c
232w lost
58.8f
14.9c
232w lost
58.8f
14.9c
233w lost
58.8f
14.9c
233w lost
58.8f
14.9c
234w lost
58.8f
14.9c
234w lost
35f/(1.7c)65.6f
18.7c
146w lost
65.6f
18.7c
146w lost
65.6f
18.7c
147w lost
65.6f
18.7c
147w lost
65.6f
18.7c
148w lost
65.6f
18.7c
148w lost
65.6f
18.7c
148w lost
65.6f
18.7c
149w lost
65.6f
18.7c
149w lost
65.6f
18.7c
150w lost
65.6f
18.7c
150w lost
40f/(4.4c)72.4f
22.4c
61w lost
72.4f
22.4c
62w lost
72.4f
22.4c
62w lost
72.4f
22.4c
63w lost
72.4f
22.4c
63w lost
72.4f
22.4c
64w lost
72.4f
22.4c
65w lost
72.4f
22.4c
65w lost
72.4f
22.4c
66w lost
72.4f
22.4c
66w lost
72.4f
22.4c
67w lost
45f/(7.2c)79.2f
26.2c
1% max
79.2f
26.2c
1% max
79.2f
26.2c
1% max
79.2f
26.2c
1% max
79.2f
26.2c
1% max
79.2f
26.2c
1% max
79.2f
26.2c
1% max
79.2f
26.2c
1% max
79.2f
26.2c
1% max
79.2f
26.2c
1% max
79.2f
26.2c
1% max
50f/(10c)82.4f
28c
7% max
82.4f
28c
7% max
84.2f
29c
7% max
84.2f
29c
7% max
84.2f
29c
7% max
84.2f
29c
7% max
84.2f
29c
7% max
84.2f
29c
8% max
84.2f
29c
8% max
84.2f
29c
8% max
84.2f
29c
8% max
55f/(12.8c)85.6f
29.8c
11% max
85.6f
29.8c
12% max
85.6f
29.8c
12% max
85.6f
29.8c
12% max
85.6f
29.8c
13% max
87.4f
30.8c
13% max
87.4f
30.8c
14% max
87.4f
30.8c
14% max
89.2f
31.8c
15% max
89.2f
31.8c
15% max
91f
32.8c
16% max
60f/(15.6c)90.6f
32.6c
16% max
90.6f
32.6c
17% max
92.4f
33.6c
17% max
92.4f
33.6c
18% max
94.2f
34.6c
19% max
94.2f
34.6c
19% max
96f
35.6c
20% max
97.8f
36.6c
21% max
99.6f
37.6c
22% max
101.4f
38.6c
23% max
103.2f
39.6c
25% max
65f/(18.3c)97.4f
36.3c
21% max
97.4f
36.3c
21% max
99.2f
37.3c
22% max
101f
38.3c
23% max
102.8f
39.3c
25% max
104.6f
40.3c
26% max
106.4f
41.3c
27% max
108.2f
42.3c
29% max
111.8f
44.3c
31% max
115.4f
46.3c
33% max
119f
48.3c
35% max
70f/(21.1c)102.4f
39.1c
25% max
104.2f
40.1c
26% max
107.8f
42.1c
28% max
109.6f
43.1c
29% max
111.4f
44.1c
31% max
115f
46.1c
33% max
118.6f
48.1c
35% max
122.2f
50.1c
38% max
125.8f
52.1c
41% max
129.4f
54.1c
45% max
134.8f
57.1c
49% max
75f/(23.9c)109.2f
42.9c
29% max
111f
43.9c
31% max
114.6f
45.9c
33% max
118.2f
47.9c
35% max
121.8f
49.9c
38% max
125.4f
51.9c
41% max
129f
53.9c
44% max
134.4f
56.9c
48% max
138f
58.9c
54% max
143.4f
61.9c
60% max
148.8f
64.9c
69% max
80f/(26.7c)114.2f
45.7c
33% max
117.8f
47.7c
35% max
121.4f
49.7c
38% max
125f
51.7c
41% max
130.4f
54.7c
45% max
134f
56.7c
49% max
139.4f
59.7c
55% max
144.8f
62.7c
62% max
150.2f
65.7c
71% max
155.6f
68.7c
84% max
Too Hot
Terminal in
~16.4 hour
85f/(29.4c)119.2f
48.4c
36% max
124.6f
51.4c
40% max
128.2f
53.4c
44% max
133.6f
56.4c
48% max
139f
59.4c
55% max
144.4f
62.4c
62% max
151.6f
66.4c
73% max
157f
69.4c
87% max
Too Hot
Terminal in
~3 hour
Too Hot
Terminal in
~48 min
Too Hot
Terminal in
~28 min
90f/(32.2c)120.6f
49.2c
37% max
124.2f
51.2c
40% max
129.6f
54.2c
45% max
136.8f
58.2c
51% max
142.2f
61.2c
58% max
147.6f
64.2c
68% max
154.8f
68.2c
81% max
Too Hot
Terminal in
~12.4 hour
Too Hot
Terminal in
~52 min
Too Hot
Terminal in
~27 min
Too Hot
Terminal in
~18 min
95f/(35c)120.2f
49c
37% max
125.6f
52c
41% max
131f
55c
46% max
138.2f
59c
53% max
145.4f
63c
61% max
150.8f
66c
74% max
158f
70c
92% max
Too Hot
Terminal in
~1.2 hour
Too Hot
Terminal in
~29 min
Too Hot
Terminal in
~18 min
Too Hot
Terminal in
~13 min
100f/(37.8c)119.8f
48.8c
37% max
127f
52.8c
41% max
132.4f
55.8c
47% max
139.6f
59.8c
55% max
146.8f
63.8c
65% max
154f
67.8c
81% max
Too Hot
Terminal in
~3.3 hour
Too Hot
Terminal in
~34 min
Too Hot
Terminal in
~19 min
Too Hot
Terminal in
~13 min
Too Hot
Terminal in
~10 min

3 Notes

  • For conditions where sweating is required to keep cool, temperatures shown are how hot it would have to be for you to sweat the same amount when walking.
    • The 'x% max' is showing what percentage of your maximum sweat evaporation is required to avoid heat build up.
  • For conditions that are cool enough that sweating is required, temperatures shown are that have the same heat loss when walking.
    • The 'x Watts' show the estimated heat loss.
  • Walking temperatures assume 30% humidity.
  • The entries 'Too Hot' indicate that not enough sweat will evaporate to keep your internal temperature stable.
  • When the conditions are too hot, the approximate time for your core temperature to rise to a critical point is given as 'Terminal in x'.
  • This utility can also display sodium losses. The sweat rate shown is based on the assumption that all sweat evaporates; if sweat is dripping off you then your actual sodium losses may be far higher. For more details see Hydration 101.

4 Input Form

Height
Weight
Pace (min/mile)
Minutes Seconds
Temperature Units
Temperature Range
Temperature Increment
Sodium Losses

5 Impact of Humidity

The graph below shows how core temperature (of walkers) on the Y-axis rises with humidity on the X-axis for different air temperatures (lines). You'll notice that at 24f/75f there is no impact of humidity on core temperature. For temperatures between 33c/92f and 45c/113f, the humidity does not change core temperature until a critical point is reached and then there is a dramatic rise. By 50c/122f, even changes in very low humidity make a big impact on core temperature. It seems reasonable that a similar response would be seen in runners, but at lower temperatures.

The effect of heat and humidity on core temperature

6 Dew Point

Runners World suggested that dew point could be used in isolation, and published the simple table shown below. This seems an overly simplistic and flawed approach. For instance, at 3:51 pm 23 Jul, Phoenix, AZ was 105f with a dew point of 55f, which the table below would say is at the low end of "Comfortable, Hard efforts likely not affected". I believe that 105f, even with low humidity would not be comfortable and it would impact my performance.

DEW POINT (°F) RUNNER\'S PERCEPTION HOW TO HANDLE
50–54 Very comfortable PR conditions
55–59 Comfortable Hard efforts likely not affected
60–64 Uncomfortable for some people Expect race times to be slower than in optimal conditions
65–69 Uncomfortable for most people Easy training runs might feel OK but difficult to race well or do hard efforts
70–74 Very humid and uncomfortable Expect pace to suffer greatly
75 or greater Extremely oppressive Skip it or dramatically alter goal

7 Other Sports

This page is focused on runners, but may apply to some other sports such as soccer. It would not apply to cycling or similar sports where there is more air movement.

8 See Also

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