Beat The Heat

Whether you're running at home or away this summer, run sun-smart, focusing on hydration, clothing and your training schedule



by Matt Gilbert

The Great British Summer™: without a doubt the best time of year to lace up and hit the ground running. But whether we’re treated to the full three-month quota of summer (no chance), or four straight days in July and a Sunday afternoon in August (odds on), it pays to run sun-smart for every second under the sun – particularly if you're travelling abroad.

Without due care, the soaring temperatures we spend months praying for will take their toll on runners. Even in cooler temperatures, your body works double-time to shift excess heat produced by working muscles during training. As the mercury rises, so does that cooling effort. And if your body struggles to keep up, you can suffer from dehydration or heat illnesses, such as cramp and heat exhaustion. Luckily, you can make life easier for your body by practising sun-smart running – focusing on hydration, clothing and your training schedule.

TRAIN SMART

Factoring in the sun’s effects on your body is good practice when planning sun-kissed training sessions. Is it absolutely necessary to go out on six-minute miles? Starting your run slowly can keep you going for longer on hot days.

"The slower you start, the longer you’ll keep your body heat from reaching a threshold," says Professor Mike Gleeson, programme leader in exercise physiology at Loughborough University. For example, if you normally start out at seven-minute-mile pace, do your first mile at eight-minute pace, then speed up later on.

If you're planning to take your training regime on holiday, acclimatise to the heat in a safe and gradual manner, not haphazardly. "For the first three days or so, keep daytime running sessions to 30 easy minutes at most," says running coach Mike Gratton.

When it comes to speed training, Gleeson advises scheduling these sessions in the cooler parts of the day; i.e. morning or evening. "Running in the hottest part of the day will put added strain on your cardiovascular system. Your heart beats that bit faster in warmer temperatures, as it pumps blood out to the skin as part of your body’s cooling system."

HYDRATION

When it comes to hydration levels, you shouldn't be short-changing your body at any time, let alone while training in warmer temperatures. Sweating – your body's cooling system – removes excess heat through evaporation. With that sweating comes fluid loss; the hotter it gets, the more you'll leak. Physiologically, fluid losses reduce blood volume, which in turn reduces stroke volume in the heart.

As a result, the heart is forced to work harder to fulfil circulation needs. Drinking to replace what you lose through sweat helps keep your blood volume constant. This replenishment keeps your working muscles happy, as blood can easily travel to and from the legs. But if your fluid levels dip too low, your blood volume will start to decrease.

Sooner or later your body reaches a point where it says there's not enough blood to deliver to the muscles for exercise. "The body's response is to restrict blood flow to these less-essential areas," says Gleeson. "Your body will choose to save your life, and deliver blood to the vital organs and not the muscles. So you slow down." Just two per cent dehydration can cause a 20 per cent reduction on your performance.

Even worse, if fluid levels aren’t topped up swiftly, you could suffer more serious problems, such as dizziness, cramps and vomiting (see System Overload). If dehydration strikes, head straight for a shaded area and fill up on water. But the best strategy is to avoid the problem altogether by keeping your fluid levels at optimum.

How's your hydration? Check the colour of your urine against the shades on our chart

To estimate your fluid needs, weigh yourself naked before and after a hard run, says Dr Neil Walsh, senior lecturer at the School of Sport Health and Exercise Science at Bangor University. "If you weigh one kilogram less after a run, you need to drink one litre of fluid to replace fluid losses." Checking the colour of your urine first thing each morning can give you a rough idea of your current hydration levels, says Walsh. "You’re well hydrated if your urine is a pale yellow and dehydrated if it is darker."

STAY-COOL KIT

Summer means vest time, right? Wrong. When it comes to keeping cool, the smart money's on loose-fitting clothing. The benefits are two-fold: you get more protection from the sun's energy-sapping heat than a vest, plus looser garments allow you to take advantage of any breeze – including the one you make on your running travels.

Fabric-wise, look for sports-specific synthetics, which stay drier and wick moisture better than natural fibres like cotton do. Colour-wise, the lighter the better, so you can reflect the sun’s rays.

You lose a large proportion of your body's heat through your head – bad news in winter, great in summer. But if the sun is particularly strong, it's a good idea to keep your noggin covered with a loose-fitting cap. Choose one with a substantial peak that’s constructed from technical fibres designed to help wick sweat away. Or you could take a leaf out of Randy Accetta's book.

The president of the Tuscon-based Southern Arizona Roadrunners, who knows a thing or two about running in the heat, recommends the 'cold cap'. "I'll soak a baseball cap in water and put it in the fridge for at least 30 minutes or overnight before a morning run," he says. "An old baseball cap retains the moisture longer than the new technical hats."

Finally, be sure to complete your get-up with a layer of sunscreen – with a minimum SPF of 15. Always opt for sweat-proof lotions, says Gleeson. "It’s crucial that your sweat can evaporate, so your body can cool itself properly." Another benefit: sunscreen decreases your skin and body temperatures, so you'll stay cooler during exercise.

SYSTEM OVERLOAD: How to recognise the signs and symptoms of heat illness
HEAT EXHAUSTION
  • Cause Failing to replace fluids and electrolytes when dehydration sets in.
  • Symptoms A core body temperature of 102°F to 104°F, headache, fatigue, profuse sweating, nausea, clammy skin.
  • Action plan Apply a cold pack on the head and neck. Restore fluid and salt balance with foods and drinks that contain sodium.

HEAT CRAMPS
  • Cause Loss of fluid and minerals (electrolytes) through respiration and sweat.
  • Symptoms Severe abdominal cramps or large-muscle cramps (such as quads and glutes).
  • Action plan Restore fluid and salt balance with foods and drinks that contain sodium (salted snack foods, sports drinks).

HEATSTROKE
  • Cause Extreme exertion, coupled with very hot, humid conditions and dehydration, impair your body’s ability to maintain an optimal temperature.
  • Symptoms A core body temperature of 104°F or above, headache, nausea, vomiting, diarrhoea, rapid pulse, disorientation.
  • Action plan Emergency medical attention necessary.

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