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There is definitely no better feeling on two wheels than when mild summer air flows around your face, forearms and calves, it smells of hay, shadows stand out sharply and it smells like barbecue food every time you pass through town! However, depending on your fitness, route or state of mind, cycling in summer can also be nasty. This is especially true when the temperatures climb very high, as they have in recent years, when the day in the saddle gets long or when it takes you to places that are extreme in other ways.
Basically, basic fitness and - almost more importantly - good self-assessment help you to avoid potential dangers or discomfort. And where people are not the solution, it depends on the material. In addition to clever ways of carrying drinks, clothing is an important companion when it comes to braving the weather, from sweat management in extreme heat to thermoregulation in changing conditions and pure protection from summer thunderstorms.
Cycling in summer: Overheated tyres
But it's not just the body's functions that change at high temperatures, the material is also affected. It is not uncommon to hear small explosions echoing through the rock faces on trips into the high mountains - once again, a tyre has blown up due to excessive pressure! Road cyclists in particular, who fill their tyres with the highest pressures in the cycling world, are affected here. They set off down in the valley with the usual eight bar and after conquering a pass they put the bike down on the grass for a break. The black rubber efficiently converts the energy of the sun's rays into heat, especially at high altitudes; the tyres and the air they contain heat up, the air expands and the pressure rises significantly to double-digit values.
It's lucky if the damage occurs in the meadow and not on the descent! The high-altitude sun has a similar effect on the brake pads of rim brakes. These already heat up a lot on long downhill rides; if they are already hot at the summit due to a lot of sunlight, the rubber can completely overheat and smear instead of generating friction. The two phenomena described above are due to alpine conditions, but on very hot days you should keep an eye on the air pressure in the tyres and the condition of the brake pads even at altitudes below 2000 metres. And if the tyres already suffer in the sun because of their dark colour, how do roads that are exposed to the sun from sunrise to sunset fare?
Cycling in summer: when the road melts
Anyone who follows the Tour de France will be familiar with the moments when racers start to slip on mountain descents because the tarmac literally melts. Technically speaking, the heat causes the bitumen, which bonds the grit to the tarmac surface, to become liquid again and pushes itself upwards out of the road surface. Darker coloured patches then indicate that the road surface is becoming increasingly slippery. Apart from the resulting risk of falling, splashes of this petroleum product can hardly be removed from the bike or clothing. Although the average touring cyclist does not plunge downhill at 110 kilometres per hour like professionals, you should still ride carefully and with foresight, especially on older roads with sloping surfaces and facing the sun.
The same also applies to particularly rough tarmac. Especially in southern Spain and Mallorca, all the locals know the effect when it finally rains again after a long dry spell: Pollen and other particles collect in the coarse pores of the carriageway and are washed up by the first rain. This forms a smear layer that comes close to soap! After a few hours, the rain will have washed the grease away again, but until then you should definitely not be out on your bike - the grip is completely unpredictable. The situation is similar in late autumn near olive groves, as our expert Dr Achim Schmidt from the Cologne Sports University recalls: lost fruit and oily tyre marks from tractors create a greasy film on the asphalt of rural roads that even rain cannot remove for a long time.
Biking in high temperatures: archenemy dehydration
Accidents caused by defective tyres or slippery roads are relatively rare; much more often it is the circulatory functions that suffer in very hot summer conditions. Heat manipulates the body on two levels: Firstly, physical labour produces a lot of heat as a waste product, so to speak. A good two thirds of all energy produced by the metabolism is converted into heat, only a quarter is used for cycling and even less for walking. In other words: the more muscle work, the more waste heat. This has to be removed to maintain the body's own biochemistry, which is why we sweat, and this in turn consumes energy.
What happens in the event of fluid loss?
Every single ionic compound that makes up salt has to be transported outwards through the skin pores using energy. Salt on the skin then causes water to diffuse through the skin to equalise the mineral concentration. The resulting sweat evaporates on the skin and cools it in this way. It is now clear why modern competitive athletes do not pour litres of water over their bodies: The body then has to transport salt to the skin again, the surge of water only provides short-term relief, but costs minerals!
In addition to the energy required for sweating, the continual loss of fluids causes a reduction in the amount of blood or a simultaneous thickening, because only the fluid is reduced, not the solid components in the blood. However, moving less and more viscous blood through the body means more pumping work for the heart; this is the reason why less fit people suffer more from exercise in the heat. Our expert Dr Achim Schmidt from the Sport University in Cologne (see interview).
Excursus: What does isotonic mean for drinks?
Every liquid has a certain concentration of dissolved particles such as salts or sugar; only distilled water has a concentration close to zero. If two such liquids with different particle concentrations meet, as occurs on the inside and outside of the intestine, for example, any concentration gradient is automatically equalised by the membrane of the intestinal wall. This is the reason why you get thirsty after eating very salty food: the salt draws water from the body into the intestine and is then absent.
Salty seawater would be a hypertonic solution with more table salt per cubic centimetre than in our blood. The body has the easiest time with isotonic solutions, which therefore come very close to those in our bloodstream in terms of the content of minerals and co. Advertising promises such as "three times as isotonic as other products" are therefore a contradiction in terms. Truly isotonic drinks are also never sweet. The mixing ratio is therefore extremely important when mixing powders, as too much or too little powder per litre of water does not produce isotonicity.
Cycling in summer: Expert interview with Dr Achim Schmidt
Dr Achim Schmidt teaches at the Institute for Outdoor Sports and Environmental Research at the Cologne Sport University and has been available to us several times not only as a scientist but also as an ambitious cyclist with a racing background.
MYBIKE: Dr Schmidt, within the professional cycling teams there are riders whose only job seems to be to bring full bottles from the team car to their captains. How much does a professional cyclist drink, and is this transferable to amateur cyclists?
Dr Schmidt: During hot stages and maximum exertion, a top professional cyclist drinks six to eight litres during the stage alone, which equates to just over one litre per hour, yet significant weight loss due to fluid loss has been observed. However, your body and especially your large intestine are also trained to absorb water efficiently. Top athletes even sweat more efficiently, i.e. with less mineral loss. An average person can only absorb about half as much fluid. It doesn't help to force more in, this is more likely to upset the water balance, in very extreme cases there is even the term water intoxication.
Drinking strategy?
MYBIKE: How much should you drink? And is there such a thing as a drinking strategy?
Dr Schmidt: Let's move away from professional sport. A healthy hobby cyclist can rely on their sense of thirst, but should also strictly orientate themselves on this and not wait for the next break or descent. It is much more efficient to drink a little at a time than to empty a bike bottle all at once at the end of an hour.
MYBIKE: Does that mean that anyone who goes on tour by bike should be able to drink while riding?
Dr Schmidt: That would be better, the vast majority of bikes have threads for bottle cages in a ready-to-grip position. You should use this if the traffic situation and surface allow it. If you have to make an extra stop, you might delay the next sip for too long. My tip for an easily accessible extra portion: a lightweight hydration pack.
What is the best drink for cycling in summer?
MYBIKE: And what belongs in the water bottle? Is the famous apple spritzer a myth or an insider tip?
Dr Schmidt: In principle, spritzers with a maximum of one third juice are a good choice, but in the high performance range you would refrain from them because of the fruit acid, and some amateur stomachs do not tolerate them so well under stress. The simplest choice is still water with an increased mineral content, especially magnesium, potassium and sodium. Only over two or three hours in the heat should isotonic sports drinks balance out both the salt sweated out and the carbohydrate reserves, otherwise I am not a big fan of such substitutions in everyday life. Oh yes, when mixing powders, strictly follow the dosing instructions - more won't help, on the contrary.
MYBIKE: There are other persistent myths about drinking. Does salt in a drink make sense, and is wheat beer really the super sports drink?
Dr Schmidt: Dissolving a crumb or two of salt in the bottle can work very well for heavy sweaters on hot days. But again, don't overdo it, otherwise you'll create a hypertonic solution, which is more likely to cause thirst than relieve it. However, the majority of people get enough salt from their food. Even if you reach for energy bars, you should drink enough immediately afterwards, otherwise the sugar in the food will draw water out. Wheat beer without alcohol is actually great for refuelling after the tour, but the carbon dioxide alone spoils the good properties on the way. The mineral content and easily digestible carbohydrates go well with sport. Alcohol generally slows down regeneration and helps you fall asleep.
Prevent fluid loss
MYBIKE: What can actually happen if you don't drink regularly enough on the bike? And how do you notice that?
Dr Schmidt: I have some very interesting figures on this. The feeling of thirst sets in at a water loss of just under two per cent of the total body mass. From just over three, you lose both physical and mental performance, become unfocussed and tired. Headaches are also a possible warning sign. At just double the two per cent, i.e. four to five, muscle strength drops significantly and many people suffer from cramps. With a fluid deficit of more than six, at the latest ten percent - which corresponds to four and a half to five litres for the average man - there is a risk of severe heat cramps and even coma. A lack of fluids has the most direct and negative impact of all deficits. Very interesting: It is our ability to get rid of heat over the entire surface of our skin that has made us humans such persistent "hunters". Cats of prey have to rest for a long time after a long sprint, otherwise they die of thermal collapse!
Not all drinking bottles are the same
The average bike has two mounting points for bottle cages, step-through and waver frames, without a top tube sometimes only one or none. And with pedelecs, the battery sometimes "blocks" precisely this point. However, there is a workaround: SKS offers, among other things, mounting clamps that replace such bottle cage threads. Modern forks often have threads on the side that are intended for panniers, but in the vast majority of cases bottle cages also fit here. The same applies to the fixing points for so-called snack bags on the top tube. If there is not enough space in the frame triangle Fidlock a magnetic holding system that releases the bottle by turning it and not by pulling it out. Price (incl. bottle connector): 24.95 euros >> available here.
The "Artica pro" insulated bottle from Zefal is currently available from Amazon on offer for 8.99 euros.
Hydration pack for cycling in summer
As our expert Dr Achim Schmidt has already recommended, a compact hydration pack with up to 2.5 litres can both solve space problems and make the drink easily accessible from the saddle. An average bike bottle holds 500 ml, the slightly larger models 750 ml. At half a litre per hour, this is enough for a maximum of three. Zefal offers a universal bottle cage that can be used to hold large bottles, for example PET bottles of up to 1.5 litres, straight from the shop. However, it also fits standard threads. Price: 59.99 euros >> available here.
Different drinking bottle materials
Drinking bottles are usually made of plastic, even in professional sport. Not only because the racers dispose of them right at the track. They are the choice because of their low weight and the ability to get more water into the mouth more quickly by squeezing them. Even though plastic bottles can be rinsed, those made of aluminium, steel or titanium are more hygienic and environmentally friendly. Although they are slower to drink and at least the steel bottles are noticeably heavier, they are more likely to retain their temperature and can be boiled. A little caution is required with aluminium models: Acids from juices, for example, form compounds with the metal that are not supposed to be healthy, whereas this is not the case with water.
Titanium bottles such as the "Podium" from Camelbak are light, hygienic and stylish, but expensive. Camelbak and Zefal, for example, offer insulated bottles, but ice-cold drinks are not as helpful in the heat as you might think. Although the coolness is good for both the skin and the stomach in the short term, it also causes the body to want to raise the core temperature again and further fuel the circulation. It is not for nothing that desert peoples drink lukewarm tea. Iso bottles are more suitable for warm drinks in winter. Another professional tip: pouring cold water over your entire body only helps temporarily against the heat. It is better to cool small, particularly suitable areas with water; temples, neck and inner wrists have proven effective here.
The "Podium steel" bottle from Camelbak with 660 ml costs just 39.99 Euro at Bergzeit. The titanium version costs 100 euros and is available e.g. from Available on Amazon.
Cycling in summer: it buzzes and floats
In addition to its many benefits, summer also brings some inconveniences that don't necessarily have anything to do with the temperature - or at least not at first glance. A persistent dry cough, nosebleeds or burning eyes can also be the result of dehydration. If there is simply not enough fluid in the body to keep the mucous membranes in the nose, mouth, throat, windpipe or eyeballs moist, dust and pollen in particular cannot be flushed out and irritate the surface. Tip: In addition to drinking enough, summer tours are a good opportunity to use unused corona masks. Allergy sufferers, in particular, can use them to block out the travelling swathes of pollen, at least for a short time.
The nettles of the oak processionary moth are even more dangerous: the wafer-thin fibres float around the nests and are extremely unpleasant on the skin and even dangerous in the respiratory tract, warns Dr Achim Schmidt. Here too, a disposable mask prevents worse. Asthmatics should never travel without their emergency spray, especially in summer. For off-road tours, we recommend checking the local news for warnings about ticks and the occurrence of the dangerous hantavirus before setting off: Dusting mouse faeces transmits this febrile infectious disease, with cases occurring quite locally.
Other dangers when cycling in summer
Extrapolated to the millions of kilometres cycled in Europe, however, such accidents are extremely rare. Insect bites are somewhat more common. They are harmless in themselves, unless you are allergic to them. In this case, however, those affected are aware of the dangers and antidotes, or the contact occurs in a particularly sensitive area. We recommend always cycling with suitable sports glasses, especially in summer! In addition to sun protection, keeping insects out at higher speeds is the argument in favour of this. Models that fit snugly on the forehead and keep sweat away from the eyes are ideal. People allergic to bees should wear helmets with a grid in the air holes; if an animal gets into the helmet, it usually stings quickly due to the situation.
But: helmet covers to protect against rain or to increase visibility do not belong on your head on long, hot tours. Ventilation through the channels in the helmet is essential, as the head gives off the most heat in relation to its surface area. Speaking of decreasing temperature: Please do not confuse solar radiation and temperature in the mountains! The UV radiation and the dry air in or rather on the mountains can have a very intensive effect on the skin and eyes despite mild temperatures. Proper care and adequate protection are therefore even more important here than in valleys or even at sea level. The best and most important tips for sun protection can be found here.
