During the recent heatwave the challenges of hillwalking, running and climbing in summer conditions have been uncomfortably obvious. From sunburn and dehydration to heat exhaustion and heat stroke, we examine a number of hot weather issues and ways to mitigate them - with expert advice from top runner Iain Ridgway and UKC's own Jack Geldard.
'It sounds obvious but many fail to plan their day to avoid climbing - or walking - in the sun' says Jack Geldard. 'Find out which way your crag faces, and time your visit to make the most of the shade. Climbing in the direct sun makes things much harder. Your boots feel tighter, your hands get sweaty and the rock feels greasy. If you can't head to a shady crag, then it is often possible to pick shady routes; a little roof or protruding corner can make all the difference in terms of a little bit of shade.'
A friend and I, let's call him Derek, set out to climb a long slabby route on the south face of the Dent d'Orlu one baking windless July day. On the sea of granite slabs shade was conspicuous by its absence, and as the sun gained strength and the rock radiated its power like an oven our water supplies began to look quite inadequate. By about 15 pitches up - I'd lost count - the heat had swollen my feet painfully inside my climbing shoes, and my head was swimming. Any enjoyment in the climbing was eclipsed by the relentless Pyrenean sun, and we prayed for cloud cover. In hidsight our mistake was obvious. What possessed us to pick a south-facing suntrap at the height of the southern French summer? I'm pretty sure none of the locals would've been so stupid. A couple of days later we headed for the east face, where a much higher starting point, a shorter route and the possibility of some (limited) afternoon shade all made for a more enjoyable experience. The same approach might pay dividends when hillwalking too, where advance planning can see you time your steepest ascents for cooler hours or times of day when the slope might be in shadow. What about scheduling a shady rest stop for an hour or two around mid-day, when the sun is at its fiercest?
"It sounds obvious but many fail to plan their day to avoid climbing - or walking - in the sun. Time your visit to make the most of the shade"
With its injunction to slip on a shirt, slop on the sunscreen and slap on a hat the famous Australian public health campaign is irritating but effective. We're lucky enough not to suffer from tropical sunshine in the UK, but it's surprising how quickly our wishy washy northern sun can still burn - as the lobster-pink loungers in every urban park and pub garden make all too clear. There's nothing big or clever about burning. Covering up with long sleeves may be a good idea for at least some of the day, while a brimmed hat serves the dual purpose of protecting the face and shading your eyes. Suncream needs to be applied liberally and often on the hill, as it tends to sweat off - an obvious point that many seem to overlook.
"Suncream needs to be applied liberally and often on the hill, as it tends to sweat off"
Heat exhaustion occurs when the body's core temperature rises from a healthy 37 degrees to anything up to 40 degrees. Symptoms include tiredness, dizzyness, nausea, vomiting, flushed skin, heavy sweating, a rapid heartbeat and confusion. Resting in cool shade, drinking and applying a wet cloth or T-shirt should help sort you out.
Heat stroke is far more serious, occurring when the body can no longer cool itself. Once core temperature exceeds 40 degrees cells begin to break down and organs can be affected. Symptoms include a sudden cessation of sweating, rapid heartbeat and breathing, cramps, confusion, anxiety, lack of coordination, hallucinations, seizures and unconsciousness. The symptoms develop more quickly with physical activity - known as exertional heatstroke. Heat stroke is a medical emergency and victims need immediate expert attention; meanwhile keep them cool and shaded, give them fluids and get them a bit wet (but don't fully immerse them in water - that has possible complications).
The all-day squint can soon leave you feeling dazzled and headachey. A pair of reasonable sunglasses makes all the difference to eye fatigue, and will help prevent UV damage to the eyes too. They needn't be expensive - in fact the more you pay for glasses the more likely you are to sit on or lose them - but do look for lenses with a European CE mark that guarantees a measure of protection from UV radiation.
When you're not slipping on a shirt it might be worth stripping it off instead. When the mercury climbs try shorts instead of trousers - or take it all the way down to your pants. Wear trainers in place of boots. Unzip any pockets and vents. Anything to cut down on overheating. Do you really need to bring waterproofs, warm jacket and gloves? If the blue-sky forecast is unequivocal then you might sensibly do without some of the usual 'essentials' to reduce the weight of your pack. An exception to this lightweight approach could be water, if it's a dry spell with less available on the hill than normal.
During a heatwave it's hard to resist dipping in streams and tarns, and a quick swim or wallow obviously helps put a lid on rising core temperature - provided you're aware of the possible dangers of cold water or currents. A cheeky dip is good clean fun too, depending who you're with of course. But you don't even have to go all the way. Just sticking a foot in could help:
'In other sports it might be better to stick your hand in a stream, but climbers want to keep their hands dry and tough, so we'll settle for feet' advises Jack.
'What am I on about? There is increasing evidence that it is possible to reduce core temperature by cooling an area of the body known as an AVA (arteriovenous anastomoses), which is an area of veins close to the skin, designed to help the body regulate heat. Your hands and feet are two of these areas. So forget the full ice bath, and just stick your feet in a mountain stream in between boulder problems!'
But when there's not enough water to get even a foot in, try soaking your T-shirt and hat instead. Since water conducts heat more effectively than air this should help keep your cool. On a recent windless round of the Knoydart hills I dunked mine in every passing pool, however sludgy and insect-infested, and with temperatures nudging the 30s and a lot of hard work to do I'm not sure I'd have made it without.
"There is increasing evidence that it is possible to reduce core temperature by cooling an area of the body known as an AVA. These include your hands and feet"
In real heat your performance is likely to be impaired, and it's important to know when it's safe to push yourself that bit harder and when you might be better advised to throttle back. Be realistic about your plans, expect things to take longer, and don't worry if you're even slower that you'd feared. Above all, pace yourself - whether you're on a hill race or just out for a nice non-competitive walk. On the afforementioned Knoydart trip I found myself a hill down on my loose schedule by evening, strength was oddly flagging and my pace was really suffering. So did I knuckle down and push on for another hard hour to get where I'd expected to be? Did I hell. I just stuck up the tent and enjoyed a leisurely summit sunset. What's the rush?
'Climbing in the hot sun makes your feet swell, and means your rock shoes feel tighter and more uncomfortable' Jack says. 'What also happens is the black rubber of the shoes absorbs the heat and they really do heat up. This makes them uncomfortable and I also find it affects performance in terms of stiffness and friction. Don't sit your shoes in the full sun at the base of the crag, hide them under a backpack or behind a tree, and keep them cool in between routes.'
...and have a nice wee sit down. Do it whenever you feel yourself getting hot and bothered. If there's no natural cover available try constructing your own with walking poles and a T-shirt.
In hot weather feet can swell and skin softens. Add slippery sweat and wet socks and you've a recipe for blisters. Try removing your footwear at every break or belay, letting your socks dry in the sun and if possible dunking feet in a cooling stream or pool - it helps with blister avoidance as well as possible core cooling. For more anti-blister tips see this recent UKH/UKC article.
Firstly avoid drinks containing alcohol and caffeine; go for plain water, dilute fruit juice or an isotonic sports drink. If you can't guarantee a water refill then you'll have to bring enough drink with you from the start, and working hard on a hot day you could easily get through more than two - three litres. There's a limit to how much liquid the body can usefully absorb at one go, with any excess normally just being excreted, so you're better off drinking little and often to roughly match the rate lost through sweating rather than downing occasional half bottles. That's probably a good argument for using a water bladder. It's possible, in extreme cases, to drink to excess, resulting in an electrolyte imbalance that can have serious consequences. So don't overdo it.
As an accomplished runner with plenty of experience in hot environments site user Iain Ridgway - co founder of RunSnowdonia - knows a thing or two about dealing with heat. Iain's competed for GB and Wales at various world trail and long distance mountain running championships, and was 4th placed (and team gold) at the 2013 World Trail Running Championships. He's done 100km in a best time of 7:19; came 3rd in the 2013 UKA 100km championships; won ultra marathons in the southern states of the USA, holding two race records in Texas and Kansas; and ran the Boston Marathon in 2:44 in 2012 when temperatures exceeded 30C, the hottest race day in its 117 year history. So what are his coping strategies when the heat is on?
'Dehydration isn't great' he says. 'The main thing is just a huge thirst, with a cracking headache. You basically think about nothing but drinking. Twice I've been caught out and got severely dehydrated; once I ended up sucking moisture out of moss, the second time literally pushing my hand into marsh and drinking. But you can re-hydrate pretty fast.'
'But two issues get confused - dehydration and overheating, and it's wrongly assumed that both are always connected. Heat exhaustion is much scarier to experience. Whilst dehydration is obviously corrected by drinking, over heating really is not. A cold drink is great but to stop overheating you need to work less, get in shade and cool down.'
'Overheating is more complex and something that is still not fully understood. And it's much harder to rectify, especially if on the move.'
'A third problem is hypnotraemia, depleted sodium, which is probably more dangerous than dehydration. You can drink too much and it can kill you. Unfortunately dehydration and heat exhaustion are now so tightly coupled that there is this myth that heat exhaustion is always linked to dehydration, and righting the latter cures the former. But it's just not true.'
How to prepare for heat?
Preparation is key for running in summer, reckons Iain, and though the demands of your average cragging or hillwalking day are rather less extreme there may be times, particularly in the hottest environments, when some pre-trip preparation is helpful too:
'To prepare for running in hot conditions obviously it is important to start the race hydrated' he says.
'I also make sure to take on board plenty of salt during the final few days. Some runners will also take electrolytes such as nuun tablets or elete water, but I just salt my food and may have a glass of salty water and eat bananas constantly, three a day normally.'
'The importance of salt is still being debated. Noakes, in waterlogged, believes we don't really need salt when running, but anecdotally most runners believe it helps. Tim Olson took salt tablets every hour during his recent Western States win (most famous 100 mile race in the US). Whilst we don't know why salt is needed, we do know that just having salt in your mouth causes signals to be sent to the brain which help you push on, so a pathway has clearly evolved. It's very similar to the response to carbohydrates in your mouth.'
'You can also acclimatise to heat, so if you suspect you will experience high temperatures during a race or on an overseas trekking trip for example, then target high temperatures when training during the preceding couple of weeks. Target the hottest part of the day, even try to get access to a heat chamber. This optimises your cooling system and also helps the body conserve salts.'
And what about when he's on go?
'When on the hill I monitor what I drink' Iain advises. 'As a general rule 500ml/hour is considered enough (but even this can be too much). Any more and you risk salt depletion. Most importantly just drink to thirst. Just don't drink to cool down. Food wise, I basically just eat bananas; I ate eight in the recent world trail running championships. They contain water, sugars and potassium - perfect hill food.'
'I also avoid ibuprofen in hot conditions. During ultra events I often take a few pills but when dehydrated it is more of a risk.'
'When you get seriously hot its like your brain becomes somewhat disconnected, you can feel a delay in your coordination, your foot hits the ground before you expect it to, sort of like running in the dark. You also get confused and feel very dizzy. The moment that happens seriously think if it's safe to continue - it probably isn't if you are out alone. I've had that twice. Once was in the UTMB (Ultra Trail du Mont Blanc) after 100km in the brutally hot race of 2008 going over one of the highest cols, so I just DNF'd ('did not finish'). The second time was in the Boston marathon, again when temperatures exceeded 30C. That time I had less distance to go but also knew I had excellent support around me so I pushed on. But that night I was in a mess, probably the worst I have ever been after a run.'
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