Winter run better for the body, say scientists

Record ID: 162493

  • Title: Winter run better for the body, say scientists
  • Date: 28th December 2016
  • Summary: CLOSE OF COMPUTER SCREEN
  • Embargoed: 12th January 2017 10:56
  • Keywords: run running winter heart marathon John Brewer jog jogging
  • Location: LONDON, ENGLAND, UK / FILE LOCATIONS
  • City: LONDON, ENGLAND, UK / FILE LOCATIONS
  • Country: United Kingdom
  • Topics: Science
  • Reuters ID: LVA0055ESRVIZ
  • Aspect Ratio: 16:9
  • Story Text: It can be hard to find the motivation to go outside for a jog during the cold winter months. But the drop in temperature could actually provide the best conditions to maximise your running performance, according to new research.
    Anecdotal reports have long suggested that cooler temperatures make running easier. But sports scientists from St. Mary's University in London believe they've proved that cooler temperatures reduce the stress on the body, including a lower heart rate and dehydration levels in comparison to warmer conditions.
    "One of the mechanisms in which we lose heat is through sweating, but we also lose heat by transporting the blood to the surface of the skin where it can lose heat out into the external environment. That puts more strain on the heart, particularly in hot conditions because it's much harder to lose heat when the external environment is warm as well," Professor John Brewer from St. Mary's told Reuters.
    "We were expecting, in all honesty, to see some differences, but not to the magnitude of difference that we saw," he added.
    They based their research on typical British conditions during the summer and winter months, with test subjects running 10 kilometres over a 40 minute period in an environmentally controlled chamber in warm 22.3 degrees Celsius (72 Fahrenheit) and cold 8 degrees Celsius (46 Fahrenheit) temperatures.
    Each participant completed three sessions during the experiment. The first identified a baseline of readings to establish a consistent testing environment across all participants in both conditions. For the second and third sessions they ran in cool and warm temperatures.
    A heart rate monitor was worn throughout the tests, with runners pausing intermittently to have a drop of blood taken from their ear-lobe to monitor blood lactate levels. Runners were also asked for their perceived measures of thermal sensation over the 40 minute run time.
    Results showed runners' heart rates were on average 6 percent higher in the warmer conditions with sweat loss of 1.3 litres on average, making the body work harder to combat dehydration.
    "Heart rates were about 6 percent higher in the hotter conditions, we found that the runners dehydrated by around 30, 38 percent more in those hotter conditions. And they found it about 30 percent easier; the test of their thermal regulation, how they felt, their perception of heat was around a third lower when they were running in cold conditions," said Brewer.
    As the body does not have to work as hard to pump blood to the skin's surface, Brewer said, running in cooler temperatures requires less energy.
    The study was commissioned by the London Winter Run Series in aid of Cancer Research UK, taking place on February 5 in London and February 12 in Manchester - with temperatures then averaging a chilly 7 degrees Celsius (44 Fahrenheit). About 18,000 runners are expected to take part.
    Brewer added that serious runners could shave off valuable seconds and even minutes to their personal best times by choosing to run in winter rather than summer.
    "If you look at top-level sports, if you look at the likes of Mo Farah running 10k and winning world and Olympic championships; the difference between success and failure is seconds, and it's certainly not minutes. We can be very confident that in cooler conditions you can certainly slice a decent percentage of time off your personal best," he said.
    "It could be those two or three minutes that make the difference between a PB [personal best] and not doing a PB, or if you're an elite runner it could be those extra few seconds that maybe help you to break a world record."
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