Tag: running

Running in the heat

This week’s Track Radio Sport and Tech discussion

Wednesday 22nd July 2026. Each week, I talk on Track Radio about technology and sport on Sonja McLaughlan‘s afternoon show (between 2.30 and 3pm). This week’s topic reflects my recent experience of running in the heat.

Running the Cotswold Way

Every year, I spend a week away running with some friends. We try to choose a route of about a hundred miles and do a bit of it everyday over about five or six days. We’ve done the coast of Anglesey, the Isle of Man, the South West Coastal Path (five sections of five days each) and the north of England’s Coast to Coast (two sections of five days each). This year, we decided to do the Cotswold Way, 103 miles from Chipping Camden to Bath. Compared to the other jaunts we’d done, I thought it would be easy but it seemed to me that it was one of the hardest we’ve ever done. I’m certain I spent more time walking than running.

(c) Steve Haake

It occurred to me that the thirty degree heat was probably something to do with it. I spoke to research physiologist Dr Alan Ruddock, to see if this was the case.

The effect of temperature on the body

I asked him about the effect of temperature on the body.

“Once you start exercising in the heat,” he said, “you have a conflicting demand for blood flow. Where does your body send the blood? Does it send it to your muscles which need the oxygen to produce energy to produce mechanical work to run? Or does it divert some blood to the skin surface to help regulate your body temperature?”

In practice, two things happen: dilation of the capillaries at the skin’s surface and of blood vessels in the muscles. This acts to reduce blood pressure and to get back to equilibrium, the heart beats faster. The heart is like the rev counter for your body: the faster the heart goes, the more energy your body is expending and the greater the potential for fatigue. Either you accept that and fuel accordingly or slow down and run or walk at a slower pace.

Josh Kerr’s 1 mile record

On the way home from our holiday, we heard that Josh Kerr had broken the one mile record in a time of 3 minutes 42.66 seconds, knocking about half a second of the previous record.

Reports state that his Brooks running suit was “crafted to enhance aerodynamics and breathability, with laser cut perforations that release heat and humidity while enhancing mobility”.

Diamond League 2026 (Franceso Mancini)

I asked Alan what the effect of temperature might have been on performance.

“None,” came the reply.

The time was far too short for any effects of temperature to have made a difference. The suit might have enhanced aerodynamics at the speed he was running, but might have had less effect on thermal regulation.

Sage advice for running in the heat

I asked Alan what his advice would have been had I spoken to him before my holiday in the Cotswolds. He advised that a bit of acclimatisation in the University’s climate chamber would have helped my body to get used to the harsh conditions of the likes of Chipping Camden and Old Sodbury. Otherwise he had just one word:

“Hydrate.”

(c) John Rawlinson

As parkrun hits 20, our latest research shows that it’s worth at least £667m to the UK. How did we get to that number and what does it mean?

Endliffe parkrun 5th October 2024

My local parkrun at Sheffield’s Endcliffe Park this last weekend was a biggie. It could’ve been the weather, it could’ve been the fact that that the university students were back, or it could’ve been that people had heard it was parkrun’s 20th birthday. By chance, our latest parkrun research paper was due to come out around now so we’d been able to time it to coincide with the birthday celebrations. It had taken me around two years to write, because we were trying to do something difficult: work out the value of parkrun.

£667m per year: really?

If want to know the full gory details, it’s here, in Plos Global Public Health. The method once you know how to do it is remarkably simple: you ask a government-mandated question about wellbeing, the answer to which economists have worked out the value of. The question is this:

“Overall, how satisfied are you with your life nowadays? where 0 is ‘not at all satisfied’ and 10 is ‘completely satisfied’.”

The trick is that, using this scale, a change of one point for a year (per person) is called a WELLBY (short for wellbeing-year). Economists tell us that this is worth £13,000. We found that after six months of parkrunning in 2019, people’s life satisfaction increased by just over a quarter of a point, valuing the change at £3,341 for a full year or £1,670 per person for the half year. There were four hundred thousand unique parkrunners that year making the total £667m.

Is all this due to parkrun?

The big question is, how much of any life satisfaction change is due to parkrun? Was it simply the number of parkruns they did? If this was the case, then the effect might be pretty small as around 60% only did only one or two parkruns. In this scenario, we estimated that only 6.4% of the £667m was due to the parkruns (or walks) themselves, meaning parkrun was worth only £40m. Even at this lowly level, every £1 invested in parkrun was worth £16.70 to the economy.

What if the life satisfaction was due to the health and social impact of parkrun? Physical health, mental health, the number of new people met and so on. In this scenario, we estimated that 27.1% of the £667m was due to parkrun, or around £226m. Every £1 invested in parkrun would be worth £98.50 to the economy.

How does parkrun work?

Our research shows that as activity increases, both mental health and physical health scores increase and that this leads to better life satisfaction. The key message here is that the £667m is real: if parkrun was to vanish overnight, then the wellbeing of parkrunners would drop a little. Current research tells us that this would have knock on effects for mental health, physical health, confidence and social connections. Illness would probably increase a little too, and performance in the workplace would drop. The government would have to pay at least £667m to get their life satisfaction back to where it was before.

Luckily, parkrun is here to stay.