Why winter is best time for a jog

WITH temperatures dropping and the nights drawing in, it can be hard to find the motivation to head for a run.

But now is actually the best time of year to go jogging – because the cold makes it easier on your body.

A study by St Mary’s University in London has found that cold conditions bring a runner’s heart rate down by 6 per cent, as less blood is pumped out to the skin to dissipate heat.

A 40-minute jog during the average British summer sees someone sweat 1.3 litres on average, making the body work harder to fight dehydration. But a run in cooler weather requires less energy, making it easier to get round quicker.

It means the cold weather could actually be the perfect time to sign up to a 10K, with better conditions potentially shaving two minutes off your personal best time.

The research, conducted as runners sign up for the London Winter Run in February, made six male athletes run for 40 minutes at 22c (72f) and 8c (46f).

At the hotter temperature, they were under greater cardiovascular strain, leading to impaired performance.

This supports previous evidence that the skin needs to have an increased blood supply when it is warm.

The extra strain on the heart is thought to come from the competition for blood flow between the skin and working muscles, both of which need to be supplied with oxygenated blood.

Sweating also causes a risk of dehydration, with a loss in body fluid as low as 2 per cent affecting performance during running.

Professor John Brewer, who carried out the research, said: ‘If you look at it from a science perspective, running in winter is much more conducive to losing heat effectively.

‘It may be nice when the sun is shining, but very quickly your body starts to overheat, so it has to cope with producing energy to get from A to B and also to keep you cool.’