Nairobi! New Delhi! Bangkok!
You are used to doing your training and racing in temps around 30℃ to 35℃, but now you’ve signed up for a 1/2 marathon in some godforsaken freezing hellhole called Washington. Or, maybe Boston.
How will the expected race-day deep-freeze temperature of 2℃ affect you?
[Hang tight, we’ll tell you!]
Is there anything you can do to prepare for it or to mitigate the effects?
I bring you another guest post from Peter Dobos, a fellow running nerd, who combines extensive academic background in kinesiology and biomechanics with many years of experience in cross-country skiing, adventure racing and other endurance sports. You may have seen his writing on various OCR platforms, and, of course, here.
What is “Cold”?
Cold is actually all about heat. There is no such thing as “cold”, there are only different amounts of heat.
Stay with me. It only sounds deep.
Because Nature obeys the Laws of Thermodynamics, everything always wants to be at the same temperature as everything else, so heat will transfer from warmer objects/areas to colder ones. When your 37℃ body is out in 2℃ air, heat flows away from any exposed skin into the atmosphere in an attempt to balance out the temperatures of your body and the Earth.
Now, you are not going to turn your surroundings from 2C to 37C with your HOTTT body alone, and, if you are to stay alive and well, your body temperature is not dropping to 2C, so this is a losing battle. You either shrug and head to the closest pub, OR layer yourself with insulation to prevent heat transfer.
What you feel as “cold” is just heat going out, not cold coming in.
Cold is Good for Running
I’m about to drop a bomb of wisdom and knowledge here. Ready?
Cold temperatures (within reason) are actually beneficial for endurance running performance. The temperature for optimal marathon performance has been measured at just over 6℃ – not exactly Miami weather. With that information in mind, the predicted temp of 2℃ suddenly isn’t looking so disastrous. However, for a heat adapted athlete that number will likely be quite a bit different…
The below table is the result of 10 years of data collection using “…the results of six European (Paris, London, Berlin) and American (Boston, Chicago, New York) marathon races from 2001 to 2010 through 1,791,972 participants’ performances (all finishers per year and race).”
As you can see, this isn’t restricted to elite runners: El Helou et al included every single finisher. Heaps of thanks should be, well, heaped upon them.
Translation of the above table: the darker row labelled “peak” is the temperature at which runners, on average, ran the fastest. It’s just above 6℃ for both men and women.
The rows above and below are colder temperatures towards the top, and warmer temperatures towards the bottom. The important column is the one labelled “Speed Loss(%)”. This gives an idea of how much each of the temperatures slowed runners down compared to the “peak” temperature. In this case, higher numbers are worse, and zero is the best possible.
As you can see, the table tops out at 20℃, which slows people down by 17% for men and 12% for women. Your normal training temperature of 30℃ isn’t even on there, but it would be a safe guesstimate to say that it would slow people down by a good 20%. I can see the wheels turning…
I train and race in conditions that slow me down 20%. Race day temps of around 2℃ would slow me down less than 1%. So compared to my usual runs….math… math… I’m 19% to the good!
Woot! I can run a PR!
Well, maybe…it depends on your legs.
The cool temperatures take a lot of load off your cardiovascular system since it doesn’t have to do double duty as a fuel pump and an air-conditioner, which is great. However, are your legs able to run at the slightly faster pace this might allow for the full distance? That I can’t tell you, so be aware of it, especially if you judge your pace strictly by heart rate or perceived effort.
Dealing with Cold
There are two different strategies for someone who will be in a cold environment:
1) work on cold adaptation
2) dress properly
The downside is that cold adaptation takes a long time – longer than for heat – so we are effectively stuck with option #2. However, since buying clothes is both a quick fix and loads of fun, we’ll call this a win.
Dressing to Excess for Success
Working in your favour is the fact that people can deal with cold much better than with heat, mostly thanks to advances in dead-animal-skin technology i.e. clothing. People can and have dressed for survival in -70℃ howling gales, and even the insane -170℃ (in the shade) of outer space. With heat, however, once you are butt naked you’ve pretty much run out of options along those lines.
There is a rule of thumb that athletes used to racing in the cold live by: if you are comfortable on the start line, then you are overdressed. A common ballpark number is to dress as if it were 10℃ warmer than it actually is. You are trading short-term discomfort for long-term comfort and performance.
As a hot-climate athlete, you can still use this guideline, but know that it will involve way more clothing and layers for you than for the locals. Your competitors might feel a bit chilled in tights, a long sleeve technical shirt, and a wind vest.
You, on the other hand, would be rushing into hypothermia-land in that same outfit, so say “no” to peer-pressure and conformity, ignore how everyone else is dressed, and layer up to your personal level of discomfort.
Too Hot in the Cold
The rationale behind the “start off cold” paradigm is that if you are warm and toasty standing around, then you will overheat massively once you get moving and will be stripping off layers within the first 5 minutes. This is where the hot-climate athlete needs to be careful. You might start thinking “sweet, I’m hot and sweating, this is what I’m used to so it’s all good.” Nay-nay.
If you don’t strip off those layers that are cooking you, then, paradoxically, you risk getting really cold as the race progresses. This is because you will soak your insulating layers, and wet clothing is a terrible insulator, especially in the wind. FYI: it’s always windy. Assuming that you are moving quickly, you’ll generate your own wind in most races, so trying not to sweat through your clothes is a must.
The Exception – Toasty Legs
A crucial exception to the “dress to be cold at the start” rule is, in the case of runners or cyclists, your lower body. These are where all the working muscles are for your race, and they perform best when they are warm. Therefore, make sure that your butt, thighs, hamstrings and calf muscles are comfortably warm standing around and during your warm-up. I find that if it’s below about 5℃ I need to wear a thin windproof shell as an outer layer on my legs to keep them from getting cold, no matter how hard I’m working. Experiment with various combinations of knee socks, tights, half-tights, light thermal underwear, and wind shells if you have a day or two before the race.
During the Run: How to be a Thermostat
Once the race has started, you have the usual things to worry about – pace, hydration, how you’re feeling – plus one very important extra: staying dry.
Yes, you’ll likely sweat a bit, but you do NOT want your clothing absolutely soaked, because that will get you really cold really fast.
The keys to staying dry-ish are to make smart clothing choices and to act like a thermostat. What I mean by being a thermostat is that you need to react and do something anytime you start feeling either too hot or too cold. By smart clothing choices I mean that in addition to using multiple lighter layers instead of one humongous parka, you select pieces that have full or at least half zippers.
Think of zippers as dimmer switches on a light. With a simple light switch, it is either all the way on or all the way off: that’s what a pullover layer is like. You don’t want those. Zippers, like dimmers, allow you much, much more control over how much heat you trap with your layers. Full zippers and pit zips on your outside layer are ideal, and you want at least a half zipper on your middle layer.
Ok, so you’ve got your clothing dialled in, so how do you use it?
Your options if you are feeling too cold are to close up all your zippers. That’s about it. If you are still too cold, then you are going to have problems, because short of mugging volunteers or fellow racers for more clothing your only option to warm up is to run faster. Thus, you want to err on the side of a little too warm rather than a little too cold with your wardrobe.
If you are starting to overheat, then you have more options and a bit more of a standardized playbook. Your best indicator that you are overheating is if your hands and fingers are toasty warm or even starting to sweat. This is because your arms, hands, and fingers act as your body’s radiator. Your arms and fingers are thin compared to other parts of your body, so the blood flow is all closer to your skin for heat exchange with the environment. Add to that the fact that your hands and fingers are basically all capillary beds right next to the surface, and that the blood has to make a return trip (getting a 2nd chance to dump heat) and you can understand why.
Here is a cool video that shows hot blood rushing into the arms and hands.
Takeaway? The first things to do when you start to heat up is to open up your front zipper(s) and take off your gloves/mitts. Don’t toss them! Simply hold them in your hands, because you’ll likely be putting them on and taking them off repeatedly. The next step is to roll your sleeves up above your elbows. After those are done then you are down to playing with which zippers are open and how much. If you’re still hot then take off your outer layer – you’ll usually be fine tying the sleeves around your waist.
A final tactic that you can try depends on how tightly racers are bunched, which is why I left it for last. You don’t want to rely on others unless you have to. If it’s windy and/or if you are feeling cold during the run despite having all your clothing on and zipped up, then run in a pack. Conversely, run on your own if you are overheating despite thermostatting steps.
Hydrate normally, as you will still be losing water and e-lytes at a significant rate, reasonably close to what you would in “normal” conditions.
— The goal is to not make your body spend energy on keeping you warm – use it all for running if possible.
— Your legs should stay warm all the time.
— Your core should be warm – but not too warm – when racing.
— Your arms and hands are used for thermostat-ing.
— Cover your head-neck-face to your personal comfort level or to account for windchill.
— Take your outfit for a 20-30 minute test run (warmup and then target pace) to make sure it’s in that sweet spot of not too cold and not too hot.
Citation: El Helou N, Tafflet M, Berthelot G, Tolaini J, Marc A, Guillaume M, et al. (2012) Impact of Environmental Parameters on Marathon Running Performance. PLoS ONE 7(5): e37407. https://doi.org/10.1371/journal.pone.0037407