Temperature extremes and heart rates

  • runnermtl

    Posts: 129

    Feb 09, 2013 10:48 PM GMT
    Hi Guys, I wonder if anyone else is training in "extreme" temperatures? I went for a run today (-12C / 10F) and noticed, as usual, that my heart rate seemed very high for the effort I was putting into it (speed+incline) compared to track running indoors or our mild summer. Does temperature affect heart rate and if so, does it affect the effectiveness of your training overall?
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    Feb 10, 2013 1:43 AM GMT
    I could be because the cold air prevent you to take ample breath.
    If so, you get less oxygen for the same effort, and you heart rate goes up.

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    Feb 10, 2013 1:54 AM GMT
    Were the streets entirely clear and dry? If not, you are expending more effort on stabilization, and it's far from trivial.
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    Feb 10, 2013 3:02 AM GMT
    How high did your heart rate go?
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    Feb 10, 2013 6:53 AM GMT
    I tried to search for a good answer for this, but couldn't find anything. It makes sense that your heart would have to beat faster to keep your body warm in the cold weather.
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    Feb 10, 2013 7:21 AM GMT
    I don't know of any evidence that low environmental temperature per say affects heart rate during exercise. But it cold be that you have to work harder to achieve the same intensity of exercise at a higher temperature. I will see what I can find out.
  • Medjai

    Posts: 2671

    Feb 10, 2013 7:30 AM GMT
    DudeInNOVA saidI tried to search for a good answer for this, but couldn't find anything. It makes sense that your heart would have to beat faster to keep your body warm in the cold weather.


    It shouldn't need to. You'd just sweat less...

    If you were running in snowy/icy conditions, the cumulative effect of the extra adjustments would definitely take its toll.
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    Feb 10, 2013 7:54 AM GMT
    Here is something that I did not consider. According to this article, your heart rate monitor may not be getting an accurate reading because you aren't sweating enough. Using a gel may create a more reliable connection for reading. I actually use this exact gel, and it works great all the time. You can get it cheap from Amazon, and the tube lasts for a long time.
  • tuffguyndc

    Posts: 4437

    Feb 10, 2013 8:53 AM GMT
    runnermtl saidHi Guys, I wonder if anyone else is training in "extreme" temperatures? I went for a run today (-12C / 10F) and noticed, as usual, that my heart rate seemed very high for the effort I was putting into it (speed+incline) compared to track running indoors or our mild summer. Does temperature affect heart rate and if so, does it affect the effectiveness of your training overall?
    well it depends buddy. i suffer from heat induced asthma so summer are really tough for me.
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    Feb 10, 2013 4:24 PM GMT

    A quick internet search revealed this:


    'An extremely important factor affecting exercise heart rate is temperature. Warmer temperatures cause the heart to beat faster and place considerable strain on the body. Simply put, when it is hot, the body must move more blood to the skin to cool it while also maintaining blood flow to the muscles. The only way to do both of these things is to increase overall blood flow, which means that the heart must beat faster. Depending on how fit you are and how hot it is, this might mean a heart rate that is 20 to 40 bpm higher than normal. Fluid intake is very important under these conditions. Sweating changes blood volume, which eventually can cause cardiac problems. The simplest and most effective intervention to address high temperature and heart rate is regular fluid intake. This helps to preserve the blood volume and prevent the heart from beating faster and faster.'

    www.humankinetics.com/excerpts/excerpts/knowing-what-affects-your-heart-rate-provides-valuable-information
  • runnermtl

    Posts: 129

    Feb 10, 2013 5:48 PM GMT
    Hi guys, thanks for your good answers. I am doing a lot of interval training at the moment so playing close attention to my heart rate. I have had problems with heart rate monitors in the past due to our "special" climate, so I had a local running store recommend one to me. I'm quite sure it's giving me accurate readings as you do get a sense of roughly how your body feels at different heart rates (you can feel the difference between 140, 160 and 180).

    I think the idea of having to compensate for slippery and mushy conditions makes sense. I also think DudeinNova's idea about the body working harder to keep warm is logical too. I don't think sweat plays much into it below a certain temperature - let me tell you that I can work up a great sweat at -10C after an hour of running at 150-160 bpm !

    @Erik - I was targeting 155 bpm but my rate sprung up to 180 bpm very easily. I found myself jogging slowly rather than running for most of the run. I can normally do 10 km in 50 minutes at around 160bpm, but in our snow and the -10, it took me 1 hour 9 minutes yesterday.
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    Feb 10, 2013 6:25 PM GMT
    It's due to vasoconstriction plus greater demand for oxygen, when you inhale the cold air your airways constrict and blood vessels on your skin constrict and increase the systemic vascular resistance. Basically your heart has to work harder to push the blood out into your system and maintain cardiac output.
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    Feb 10, 2013 6:40 PM GMT
    Hey RunnerMtl,

    You are wearing HRM for reasons, if you are certain it is providing correct info,
    then you need to trust it. I too wear one, especially if my run is going to be longer than 1 hour. They do provide an incredible volume of info.

    However, as a Cardiovascular Healthcare professional, Heart Rate will decrease as body temprature does. Elevating core temp will increase HR.

    My thought as an athlete is:
    You said your total time increased about 40% for the distance.
    You had an increased workload.

    Perhaps you wear tired, had a poor nutrition day, dehydrated, etc.
    For some reason you had a "bad run day" They happen to all runners.

    Sub 50 min 10K. is very respectable,
    Remember running RacePace daily does not lead to long term injury free PR's. But utilizing your HRM will. They are a fun tool.

    Best of Luck....

    PS: How are you feeling the day following your workout? Increase in time/HR can also mean you are sick.

  • Feb 10, 2013 6:50 PM GMT
    runnermtl saidHi Guys, I wonder if anyone else is training in "extreme" temperatures? I went for a run today (-12C / 10F) and noticed, as usual, that my heart rate seemed very high for the effort I was putting into it (speed+incline) compared to track running indoors or our mild summer. Does temperature affect heart rate and if so, does it affect the effectiveness of your training overall?


    So here's the 'technical answer':

    This is analogous to something called the cold pressor test (http://en.wikipedia.org/wiki/Cold_pressor_test), which involves how your body reacts to cold. When exposed to cold, your vasculature begins to vasoconstrict in the periphery, which is a fancy way of saying that it redirects blood to your core to preserve body heat. As a result of this, your body will have an increased afterload (the pressure in the aorta that the heart has to pump against) and an increased pulse pressure (the difference between the two #'s when you get a blood pressure taken). This is just from the regular cold.

    Now we add in exercise to this cold weather. Like all other exercise, you're body is trying to increase cardiac output (the total amount of blood pumped by the heart in a min). There are only 2 ways to do this. One is to increase the amount of blood per pump, which is hard for the heart to do since the afterload is already high (you're pumping against a higher pressure). Two, what the body does do, is to increase the heart rate. This helps the body increase cardiac output.

    The reason that HR doesn't go as high (usually) during normal temperature exercise is that the body can dilate venous lakes in the skin, allowing more blood flow to the skin and more heat to be lost. When this happens, the size of the whole blood vessel system in aggregate increases and the vasculature can operate at a lower level of pressure. Because the pressure is lower, the afterload is lower, and now the body can compensate by increasing the amount of blood per pump and the heart rate, instead of only being able to change the heart rate.
  • MuscleComeBac...

    Posts: 2376

    Feb 10, 2013 6:55 PM GMT
    Kai808 saidIt's due to vasoconstriction, when you inhale the cold air your blood vessels constrict and increase the systemic vascular resistance. Basically your heart has to work harder to push the blood out into your system and maintain cardiac output.


    I was taught this. As well as the effects of altitude and humidity - or lack thereof - and how your body cools itself in extreme conditions (e.g. Dry desert vs muggy tropics).
    It's not dimply aerobic conditioning that is affected. I had a powerlifting client who moved from Colorado to Florida and his heart rate took a couple of months to normalize to recorded pulse rates from when he was living in Denver. I always have to adjust functional training such as Prowler sled work according to time of day, time of year and air conditions. I purposefully wean powerlifters out if air conditioning into an open garage in the weeks leading up to a meet. Something taught to me by a very smart young nationally ranked lifter who was a colleague early on in my work.

    I know that although I train less than a handful of long distance runners, I monitor their HR and BP regularly when temps change and humidity shifts. This year's Disney marathons (as I was told) had a spike in cardiac related incidents. (Although Disney doesn't release stats like that - I knew several docs and some RNs staffing those units) Some docs attributed to it being considerably warmer than usual and many out of towners training in markedly colder climes prior to arriving in what was more like late spring than mid winter in Orlando.
  • MuscleComeBac...

    Posts: 2376

    Feb 10, 2013 6:58 PM GMT
    FunStudentAndrew said
    runnermtl saidHi Guys, I wonder if anyone else is training in "extreme" temperatures? I went for a run today (-12C / 10F) and noticed, as usual, that my heart rate seemed very high for the effort I was putting into it (speed+incline) compared to track running indoors or our mild summer. Does temperature affect heart rate and if so, does it affect the effectiveness of your training overall?


    So here's the 'technical answer':

    This is analogous to something called the cold pressor test (http://en.wikipedia.org/wiki/Cold_pressor_test), which involves how your body reacts to cold. When exposed to cold, your vasculature begins to vasoconstrict in the periphery, which is a fancy way of saying that it redirects blood to your core to preserve body heat. As a result of this, your body will have an increased afterload (the pressure in the aorta that the heart has to pump against) and an increased pulse pressure (the difference between the two #'s when you get a blood pressure taken). This is just from the regular cold.

    Now we add in exercise to this cold weather. Like all other exercise, you're body is trying to increase cardiac output (the total amount of blood pumped by the heart in a min). There are only 2 ways to do this. One is to increase the amount of blood per pump, which is hard for the heart to do since the afterload is already high (you're pumping against a higher pressure). Two, what the body does do, is to increase the heart rate. This helps the body increase cardiac output.

    The reason that HR doesn't go as high (usually) during normal temperature exercise is that the body can dilate venous lakes in the skin, allowing more blood flow to the skin and more heat to be lost. When this happens, the size of the whole blood vessel system in aggregate increases and the vasculature can operate at a lower level of pressure. Because the pressure is lower, the afterload is lower, and now the body can compensate by increasing the amount of blood per pump and the heart rate, instead of only being able to change the heart rate.


    Question: what role does altitude play in this?
  • MuscleComeBac...

    Posts: 2376

    Feb 10, 2013 6:59 PM GMT
    intensity69 saidWere the streets entirely clear and dry? If not, you are expending more effort on stabilization, and it's far from trivial.


    Great point.
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    Feb 10, 2013 7:03 PM GMT
    Altitude has to do with oxygen delivery. There's less oxygen at higher altitudes. Hemoglobin is affected, hemoglobin is what delivers oxygen to the tissues. Someone who moves from a place from lower altitude to higher altitude will initially have issues with oxygenation, but the body will start
    Compensating by producing more hemoglobin.
  • MuscleComeBac...

    Posts: 2376

    Feb 10, 2013 7:12 PM GMT
    Kai808 saidAltitude has to do with oxygen delivery. There's less oxygen at higher altitudes. Hemoglobin is affected, hemoglobin is what delivers oxygen to the tissues. Someone who moves from a place from lower altitude to higher altitude will initially have issues with oxygenation, but the body will start
    Compensating by producing more hemoglobin.


    Thanks. Got that, just wondering if there's research showing cause and effect in other areas such as effects on vascodialation. Talking extremes here.
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    Feb 10, 2013 8:37 PM GMT
    MuscleComeBack said
    Kai808 saidAltitude has to do with oxygen delivery. There's less oxygen at higher altitudes. Hemoglobin is affected, hemoglobin is what delivers oxygen to the tissues. Someone who moves from a place from lower altitude to higher altitude will initially have issues with oxygenation, but the body will start
    Compensating by producing more hemoglobin.


    Thanks. Got that, just wondering if there's research showing cause and effect in other areas such as effects on vascodialation. Talking extremes here.


    Vasodilation can caused by different things. It is mainly a compensatory mechanism. What kind of extremes are you talking about, temperature or vasodilation ?
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    Feb 10, 2013 9:00 PM GMT
    That sounds too extreme to me. ;p
  • MuscleComeBac...

    Posts: 2376

    Feb 10, 2013 9:05 PM GMT
    Kai808 said
    MuscleComeBack said
    Kai808 saidAltitude has to do with oxygen delivery. There's less oxygen at higher altitudes. Hemoglobin is affected, hemoglobin is what delivers oxygen to the tissues. Someone who moves from a place from lower altitude to higher altitude will initially have issues with oxygenation, but the body will start
    Compensating by producing more hemoglobin.


    Thanks. Got that, just wondering if there's research showing cause and effect in other areas such as effects on vascodialation. Talking extremes here.


    Vasodilation can caused by different things. It is mainly a compensatory mechanism. What kind of extremes are you talking about, temperature or vasodilation ?


    Altitude
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    Feb 10, 2013 9:15 PM GMT
    minox saidI could be because the cold air prevent you to take ample breath.
    If so, you get less oxygen for the same effort, and you heart rate goes up.

    This is why I cannot function properly in cold weather, and the #1 reason that I will never permanently move away from South Florida.
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    Feb 10, 2013 11:33 PM GMT
    MuscleComeBack said
    Kai808 said
    MuscleComeBack said
    Kai808 saidAltitude has to do with oxygen delivery. There's less oxygen at higher altitudes. Hemoglobin is affected, hemoglobin is what delivers oxygen to the tissues. Someone who moves from a place from lower altitude to higher altitude will initially have issues with oxygenation, but the body will start
    Compensating by producing more hemoglobin.


    Thanks. Got that, just wondering if there's research showing cause and effect in other areas such as effects on vascodialation. Talking extremes here.


    Vasodilation can caused by different things. It is mainly a compensatory mechanism. What kind of extremes are you talking about, temperature or vasodilation ?


    Altitude


    At an extreme altitude your body would be oxygen deprived, your organs will start to shut down, compensatory mechanisms would take over and shunt blood to your most vital organs (liver, heart, brain and kidneys), then those compensatory mechanisms would stop working, which then leads to multiple organ dysfunction syndrome and the death. That's why cabins are pressurized on airplanes and fighter jet pilots use an oxygen mask when they're flying high up.
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    Feb 10, 2013 11:42 PM GMT
    I was wondering about vasoconstriction in this discussion. It makes sense when you first start running, but as you continue, wouldn't your body warm up and the vasoconstriction would no longer be needed?